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docs: ftrace: always use canonical ftrace path
The canonical location for the tracefs filesystem is at /sys/kernel/tracing. But, from Documentation/trace/ftrace.rst: Before 4.1, all ftrace tracing control files were within the debugfs file system, which is typically located at /sys/kernel/debug/tracing. For backward compatibility, when mounting the debugfs file system, the tracefs file system will be automatically mounted at: /sys/kernel/debug/tracing Many parts of Documentation still reference this older debugfs path, so let's update them to avoid confusion. Signed-off-by: Ross Zwisler <zwisler@google.com> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> Link: https://lore.kernel.org/r/20230125213251.2013791-1-zwisler@google.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
This commit is contained in:
Ross Zwisler
committed by
Jonathan Corbet
Jonathan Corbet
parent
b05ada5615
commit
2abfcd293b
@@ -6288,7 +6288,7 @@
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that can be enabled or disabled just as if you were
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to echo the option name into
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/sys/kernel/debug/tracing/trace_options
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/sys/kernel/tracing/trace_options
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For example, to enable stacktrace option (to dump the
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stack trace of each event), add to the command line:
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@@ -6321,7 +6321,7 @@
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[FTRACE] enable this option to disable tracing when a
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warning is hit. This turns off "tracing_on". Tracing can
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be enabled again by echoing '1' into the "tracing_on"
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file located in /sys/kernel/debug/tracing/
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file located in /sys/kernel/tracing/
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This option is useful, as it disables the trace before
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the WARNING dump is called, which prevents the trace to
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@@ -25,7 +25,7 @@ References
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- In order to locate kernel-generated OS jitter on CPU N:
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cd /sys/kernel/debug/tracing
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cd /sys/kernel/tracing
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echo 1 > max_graph_depth # Increase the "1" for more detail
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echo function_graph > current_tracer
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# run workload
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@@ -712,7 +712,7 @@ it works in the `active mode <Active Mode_>`_.
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The following sequence of shell commands can be used to enable them and see
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their output (if the kernel is generally configured to support event tracing)::
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# cd /sys/kernel/debug/tracing/
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# cd /sys/kernel/tracing/
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# echo 1 > events/power/pstate_sample/enable
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# echo 1 > events/power/cpu_frequency/enable
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# cat trace
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@@ -732,7 +732,7 @@ The ``ftrace`` interface can be used for low-level diagnostics of
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P-state is called, the ``ftrace`` filter can be set to
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:c:func:`intel_pstate_set_pstate`::
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# cd /sys/kernel/debug/tracing/
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# cd /sys/kernel/tracing/
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# cat available_filter_functions | grep -i pstate
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intel_pstate_set_pstate
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intel_pstate_cpu_init
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@@ -370,8 +370,8 @@ of possible problems:
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The first one can be tracked using tracing: ::
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$ echo workqueue:workqueue_queue_work > /sys/kernel/debug/tracing/set_event
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$ cat /sys/kernel/debug/tracing/trace_pipe > out.txt
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$ echo workqueue:workqueue_queue_work > /sys/kernel/tracing/set_event
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$ cat /sys/kernel/tracing/trace_pipe > out.txt
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(wait a few secs)
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^C
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@@ -344,8 +344,8 @@ Documentation/ABI/testing/sysfs-bus-iio for IIO ABIs to user space.
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To debug ISH, event tracing mechanism is used. To enable debug logs::
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echo 1 > /sys/kernel/debug/tracing/events/intel_ish/enable
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cat /sys/kernel/debug/tracing/trace
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echo 1 > /sys/kernel/tracing/events/intel_ish/enable
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cat /sys/kernel/tracing/trace
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3.8 ISH IIO sysfs Example on Lenovo thinkpad Yoga 260
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-----------------------------------------------------
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@@ -548,42 +548,42 @@ mlx5 tracepoints
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mlx5 driver provides internal tracepoints for tracking and debugging using
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kernel tracepoints interfaces (refer to Documentation/trace/ftrace.rst).
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For the list of support mlx5 events, check `/sys/kernel/debug/tracing/events/mlx5/`.
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For the list of support mlx5 events, check /sys/kernel/tracing/events/mlx5/
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tc and eswitch offloads tracepoints:
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- mlx5e_configure_flower: trace flower filter actions and cookies offloaded to mlx5::
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$ echo mlx5:mlx5e_configure_flower >> /sys/kernel/debug/tracing/set_event
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$ cat /sys/kernel/debug/tracing/trace
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$ echo mlx5:mlx5e_configure_flower >> /sys/kernel/tracing/set_event
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$ cat /sys/kernel/tracing/trace
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...
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tc-6535 [019] ...1 2672.404466: mlx5e_configure_flower: cookie=0000000067874a55 actions= REDIRECT
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- mlx5e_delete_flower: trace flower filter actions and cookies deleted from mlx5::
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$ echo mlx5:mlx5e_delete_flower >> /sys/kernel/debug/tracing/set_event
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$ cat /sys/kernel/debug/tracing/trace
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$ echo mlx5:mlx5e_delete_flower >> /sys/kernel/tracing/set_event
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$ cat /sys/kernel/tracing/trace
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...
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tc-6569 [010] .N.1 2686.379075: mlx5e_delete_flower: cookie=0000000067874a55 actions= NULL
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- mlx5e_stats_flower: trace flower stats request::
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$ echo mlx5:mlx5e_stats_flower >> /sys/kernel/debug/tracing/set_event
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$ cat /sys/kernel/debug/tracing/trace
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$ echo mlx5:mlx5e_stats_flower >> /sys/kernel/tracing/set_event
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$ cat /sys/kernel/tracing/trace
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...
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tc-6546 [010] ...1 2679.704889: mlx5e_stats_flower: cookie=0000000060eb3d6a bytes=0 packets=0 lastused=4295560217
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- mlx5e_tc_update_neigh_used_value: trace tunnel rule neigh update value offloaded to mlx5::
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$ echo mlx5:mlx5e_tc_update_neigh_used_value >> /sys/kernel/debug/tracing/set_event
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$ cat /sys/kernel/debug/tracing/trace
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$ echo mlx5:mlx5e_tc_update_neigh_used_value >> /sys/kernel/tracing/set_event
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$ cat /sys/kernel/tracing/trace
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...
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kworker/u48:4-8806 [009] ...1 55117.882428: mlx5e_tc_update_neigh_used_value: netdev: ens1f0 IPv4: 1.1.1.10 IPv6: ::ffff:1.1.1.10 neigh_used=1
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- mlx5e_rep_neigh_update: trace neigh update tasks scheduled due to neigh state change events::
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$ echo mlx5:mlx5e_rep_neigh_update >> /sys/kernel/debug/tracing/set_event
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$ cat /sys/kernel/debug/tracing/trace
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$ echo mlx5:mlx5e_rep_neigh_update >> /sys/kernel/tracing/set_event
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$ cat /sys/kernel/tracing/trace
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...
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kworker/u48:7-2221 [009] ...1 1475.387435: mlx5e_rep_neigh_update: netdev: ens1f0 MAC: 24:8a:07:9a:17:9a IPv4: 1.1.1.10 IPv6: ::ffff:1.1.1.10 neigh_connected=1
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@@ -592,14 +592,14 @@ Bridge offloads tracepoints:
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- mlx5_esw_bridge_fdb_entry_init: trace bridge FDB entry offloaded to mlx5::
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$ echo mlx5:mlx5_esw_bridge_fdb_entry_init >> set_event
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$ cat /sys/kernel/debug/tracing/trace
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$ cat /sys/kernel/tracing/trace
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...
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kworker/u20:9-2217 [003] ...1 318.582243: mlx5_esw_bridge_fdb_entry_init: net_device=enp8s0f0_0 addr=e4:fd:05:08:00:02 vid=0 flags=0 used=0
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- mlx5_esw_bridge_fdb_entry_cleanup: trace bridge FDB entry deleted from mlx5::
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$ echo mlx5:mlx5_esw_bridge_fdb_entry_cleanup >> set_event
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$ cat /sys/kernel/debug/tracing/trace
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$ cat /sys/kernel/tracing/trace
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...
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ip-2581 [005] ...1 318.629871: mlx5_esw_bridge_fdb_entry_cleanup: net_device=enp8s0f0_1 addr=e4:fd:05:08:00:03 vid=0 flags=0 used=16
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@@ -607,7 +607,7 @@ Bridge offloads tracepoints:
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mlx5::
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$ echo mlx5:mlx5_esw_bridge_fdb_entry_refresh >> set_event
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$ cat /sys/kernel/debug/tracing/trace
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$ cat /sys/kernel/tracing/trace
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...
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kworker/u20:8-3849 [003] ...1 466716: mlx5_esw_bridge_fdb_entry_refresh: net_device=enp8s0f0_0 addr=e4:fd:05:08:00:02 vid=3 flags=0 used=0
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@@ -615,7 +615,7 @@ Bridge offloads tracepoints:
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representor::
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$ echo mlx5:mlx5_esw_bridge_vlan_create >> set_event
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$ cat /sys/kernel/debug/tracing/trace
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$ cat /sys/kernel/tracing/trace
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...
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ip-2560 [007] ...1 318.460258: mlx5_esw_bridge_vlan_create: vid=1 flags=6
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@@ -623,7 +623,7 @@ Bridge offloads tracepoints:
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representor::
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$ echo mlx5:mlx5_esw_bridge_vlan_cleanup >> set_event
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$ cat /sys/kernel/debug/tracing/trace
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$ cat /sys/kernel/tracing/trace
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...
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bridge-2582 [007] ...1 318.653496: mlx5_esw_bridge_vlan_cleanup: vid=2 flags=8
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@@ -631,7 +631,7 @@ Bridge offloads tracepoints:
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device::
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$ echo mlx5:mlx5_esw_bridge_vport_init >> set_event
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$ cat /sys/kernel/debug/tracing/trace
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$ cat /sys/kernel/tracing/trace
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...
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ip-2560 [007] ...1 318.458915: mlx5_esw_bridge_vport_init: vport_num=1
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@@ -639,7 +639,7 @@ Bridge offloads tracepoints:
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device::
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$ echo mlx5:mlx5_esw_bridge_vport_cleanup >> set_event
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$ cat /sys/kernel/debug/tracing/trace
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$ cat /sys/kernel/tracing/trace
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...
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ip-5387 [000] ...1 573713: mlx5_esw_bridge_vport_cleanup: vport_num=1
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@@ -647,43 +647,43 @@ Eswitch QoS tracepoints:
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- mlx5_esw_vport_qos_create: trace creation of transmit scheduler arbiter for vport::
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$ echo mlx5:mlx5_esw_vport_qos_create >> /sys/kernel/debug/tracing/set_event
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$ cat /sys/kernel/debug/tracing/trace
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$ echo mlx5:mlx5_esw_vport_qos_create >> /sys/kernel/tracing/set_event
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$ cat /sys/kernel/tracing/trace
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...
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<...>-23496 [018] .... 73136.838831: mlx5_esw_vport_qos_create: (0000:82:00.0) vport=2 tsar_ix=4 bw_share=0, max_rate=0 group=000000007b576bb3
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- mlx5_esw_vport_qos_config: trace configuration of transmit scheduler arbiter for vport::
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$ echo mlx5:mlx5_esw_vport_qos_config >> /sys/kernel/debug/tracing/set_event
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$ cat /sys/kernel/debug/tracing/trace
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$ echo mlx5:mlx5_esw_vport_qos_config >> /sys/kernel/tracing/set_event
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$ cat /sys/kernel/tracing/trace
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...
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<...>-26548 [023] .... 75754.223823: mlx5_esw_vport_qos_config: (0000:82:00.0) vport=1 tsar_ix=3 bw_share=34, max_rate=10000 group=000000007b576bb3
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- mlx5_esw_vport_qos_destroy: trace deletion of transmit scheduler arbiter for vport::
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$ echo mlx5:mlx5_esw_vport_qos_destroy >> /sys/kernel/debug/tracing/set_event
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$ cat /sys/kernel/debug/tracing/trace
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$ echo mlx5:mlx5_esw_vport_qos_destroy >> /sys/kernel/tracing/set_event
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$ cat /sys/kernel/tracing/trace
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...
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<...>-27418 [004] .... 76546.680901: mlx5_esw_vport_qos_destroy: (0000:82:00.0) vport=1 tsar_ix=3
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- mlx5_esw_group_qos_create: trace creation of transmit scheduler arbiter for rate group::
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$ echo mlx5:mlx5_esw_group_qos_create >> /sys/kernel/debug/tracing/set_event
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$ cat /sys/kernel/debug/tracing/trace
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$ echo mlx5:mlx5_esw_group_qos_create >> /sys/kernel/tracing/set_event
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$ cat /sys/kernel/tracing/trace
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...
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<...>-26578 [008] .... 75776.022112: mlx5_esw_group_qos_create: (0000:82:00.0) group=000000008dac63ea tsar_ix=5
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- mlx5_esw_group_qos_config: trace configuration of transmit scheduler arbiter for rate group::
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$ echo mlx5:mlx5_esw_group_qos_config >> /sys/kernel/debug/tracing/set_event
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$ cat /sys/kernel/debug/tracing/trace
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$ echo mlx5:mlx5_esw_group_qos_config >> /sys/kernel/tracing/set_event
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$ cat /sys/kernel/tracing/trace
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...
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<...>-27303 [020] .... 76461.455356: mlx5_esw_group_qos_config: (0000:82:00.0) group=000000008dac63ea tsar_ix=5 bw_share=100 max_rate=20000
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- mlx5_esw_group_qos_destroy: trace deletion of transmit scheduler arbiter for group::
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$ echo mlx5:mlx5_esw_group_qos_destroy >> /sys/kernel/debug/tracing/set_event
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$ cat /sys/kernel/debug/tracing/trace
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$ echo mlx5:mlx5_esw_group_qos_destroy >> /sys/kernel/tracing/set_event
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$ cat /sys/kernel/tracing/trace
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...
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<...>-27418 [006] .... 76547.187258: mlx5_esw_group_qos_destroy: (0000:82:00.0) group=000000007b576bb3 tsar_ix=1
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@@ -691,56 +691,56 @@ SF tracepoints:
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- mlx5_sf_add: trace addition of the SF port::
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$ echo mlx5:mlx5_sf_add >> /sys/kernel/debug/tracing/set_event
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$ cat /sys/kernel/debug/tracing/trace
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$ echo mlx5:mlx5_sf_add >> /sys/kernel/tracing/set_event
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$ cat /sys/kernel/tracing/trace
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...
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devlink-9363 [031] ..... 24610.188722: mlx5_sf_add: (0000:06:00.0) port_index=32768 controller=0 hw_id=0x8000 sfnum=88
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- mlx5_sf_free: trace freeing of the SF port::
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$ echo mlx5:mlx5_sf_free >> /sys/kernel/debug/tracing/set_event
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$ cat /sys/kernel/debug/tracing/trace
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$ echo mlx5:mlx5_sf_free >> /sys/kernel/tracing/set_event
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$ cat /sys/kernel/tracing/trace
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...
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devlink-9830 [038] ..... 26300.404749: mlx5_sf_free: (0000:06:00.0) port_index=32768 controller=0 hw_id=0x8000
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- mlx5_sf_hwc_alloc: trace allocating of the hardware SF context::
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$ echo mlx5:mlx5_sf_hwc_alloc >> /sys/kernel/debug/tracing/set_event
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$ cat /sys/kernel/debug/tracing/trace
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$ echo mlx5:mlx5_sf_hwc_alloc >> /sys/kernel/tracing/set_event
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$ cat /sys/kernel/tracing/trace
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...
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devlink-9775 [031] ..... 26296.385259: mlx5_sf_hwc_alloc: (0000:06:00.0) controller=0 hw_id=0x8000 sfnum=88
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- mlx5_sf_hwc_free: trace freeing of the hardware SF context::
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$ echo mlx5:mlx5_sf_hwc_free >> /sys/kernel/debug/tracing/set_event
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$ cat /sys/kernel/debug/tracing/trace
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$ echo mlx5:mlx5_sf_hwc_free >> /sys/kernel/tracing/set_event
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$ cat /sys/kernel/tracing/trace
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...
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kworker/u128:3-9093 [046] ..... 24625.365771: mlx5_sf_hwc_free: (0000:06:00.0) hw_id=0x8000
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- mlx5_sf_hwc_deferred_free : trace deferred freeing of the hardware SF context::
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$ echo mlx5:mlx5_sf_hwc_deferred_free >> /sys/kernel/debug/tracing/set_event
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$ cat /sys/kernel/debug/tracing/trace
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$ echo mlx5:mlx5_sf_hwc_deferred_free >> /sys/kernel/tracing/set_event
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$ cat /sys/kernel/tracing/trace
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...
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devlink-9519 [046] ..... 24624.400271: mlx5_sf_hwc_deferred_free: (0000:06:00.0) hw_id=0x8000
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- mlx5_sf_vhca_event: trace SF vhca event and state::
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$ echo mlx5:mlx5_sf_vhca_event >> /sys/kernel/debug/tracing/set_event
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$ cat /sys/kernel/debug/tracing/trace
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$ echo mlx5:mlx5_sf_vhca_event >> /sys/kernel/tracing/set_event
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$ cat /sys/kernel/tracing/trace
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...
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kworker/u128:3-9093 [046] ..... 24625.365525: mlx5_sf_vhca_event: (0000:06:00.0) hw_id=0x8000 sfnum=88 vhca_state=1
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- mlx5_sf_dev_add : trace SF device add event::
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$ echo mlx5:mlx5_sf_dev_add>> /sys/kernel/debug/tracing/set_event
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$ cat /sys/kernel/debug/tracing/trace
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$ echo mlx5:mlx5_sf_dev_add>> /sys/kernel/tracing/set_event
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$ cat /sys/kernel/tracing/trace
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...
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kworker/u128:3-9093 [000] ..... 24616.524495: mlx5_sf_dev_add: (0000:06:00.0) sfdev=00000000fc5d96fd aux_id=4 hw_id=0x8000 sfnum=88
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- mlx5_sf_dev_del : trace SF device delete event::
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$ echo mlx5:mlx5_sf_dev_del >> /sys/kernel/debug/tracing/set_event
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$ cat /sys/kernel/debug/tracing/trace
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$ echo mlx5:mlx5_sf_dev_del >> /sys/kernel/tracing/set_event
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$ cat /sys/kernel/tracing/trace
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...
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kworker/u128:3-9093 [044] ..... 24624.400749: mlx5_sf_dev_del: (0000:06:00.0) sfdev=00000000fc5d96fd aux_id=4 hw_id=0x8000 sfnum=88
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@@ -651,14 +651,14 @@ via power-saving behavior.
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Enabling all tracepoints can be done like
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::
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# echo 1 > /sys/kernel/debug/tracing/events/hda/enable
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# echo 1 > /sys/kernel/tracing/events/hda/enable
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then after some commands, you can traces from
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/sys/kernel/debug/tracing/trace file. For example, when you want to
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/sys/kernel/tracing/trace file. For example, when you want to
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trace what codec command is sent, enable the tracepoint like:
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::
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# cat /sys/kernel/debug/tracing/trace
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# cat /sys/kernel/tracing/trace
|
||||
# tracer: nop
|
||||
#
|
||||
# TASK-PID CPU# TIMESTAMP FUNCTION
|
||||
|
||||
@@ -8,7 +8,7 @@ at https://www.intel.com/sdm (Volume 3)
|
||||
|
||||
Available trace points:
|
||||
|
||||
/sys/kernel/debug/tracing/events/msr/
|
||||
/sys/kernel/tracing/events/msr/
|
||||
|
||||
Trace MSR reads:
|
||||
|
||||
@@ -34,7 +34,7 @@ rdpmc
|
||||
|
||||
The trace data can be post processed with the postprocess/decode_msr.py script::
|
||||
|
||||
cat /sys/kernel/debug/tracing/trace | decode_msr.py /usr/src/linux/include/asm/msr-index.h
|
||||
cat /sys/kernel/tracing/trace | decode_msr.py /usr/src/linux/include/asm/msr-index.h
|
||||
|
||||
to add symbolic MSR names.
|
||||
|
||||
|
||||
@@ -4,7 +4,7 @@ NMI Trace Events
|
||||
|
||||
These events normally show up here:
|
||||
|
||||
/sys/kernel/debug/tracing/events/nmi
|
||||
/sys/kernel/tracing/events/nmi
|
||||
|
||||
|
||||
nmi_handler
|
||||
@@ -31,13 +31,13 @@ really hogging a lot of CPU time, like a millisecond at a time.
|
||||
Note that the kernel's output is in milliseconds, but the input
|
||||
to the filter is in nanoseconds! You can filter on 'delta_ns'::
|
||||
|
||||
cd /sys/kernel/debug/tracing/events/nmi/nmi_handler
|
||||
cd /sys/kernel/tracing/events/nmi/nmi_handler
|
||||
echo 'handler==0xffffffff81625600 && delta_ns>1000000' > filter
|
||||
echo 1 > enable
|
||||
|
||||
Your output would then look like::
|
||||
|
||||
$ cat /sys/kernel/debug/tracing/trace_pipe
|
||||
$ cat /sys/kernel/tracing/trace_pipe
|
||||
<idle>-0 [000] d.h3 505.397558: nmi_handler: perf_event_nmi_handler() delta_ns: 3236765 handled: 1
|
||||
<idle>-0 [000] d.h3 505.805893: nmi_handler: perf_event_nmi_handler() delta_ns: 3174234 handled: 1
|
||||
<idle>-0 [000] d.h3 506.158206: nmi_handler: perf_event_nmi_handler() delta_ns: 3084642 handled: 1
|
||||
|
||||
@@ -24,27 +24,27 @@ tracing information should be printed.
|
||||
---------------------------------
|
||||
|
||||
The events which are available for tracing can be found in the file
|
||||
/sys/kernel/debug/tracing/available_events.
|
||||
/sys/kernel/tracing/available_events.
|
||||
|
||||
To enable a particular event, such as 'sched_wakeup', simply echo it
|
||||
to /sys/kernel/debug/tracing/set_event. For example::
|
||||
to /sys/kernel/tracing/set_event. For example::
|
||||
|
||||
# echo sched_wakeup >> /sys/kernel/debug/tracing/set_event
|
||||
# echo sched_wakeup >> /sys/kernel/tracing/set_event
|
||||
|
||||
.. Note:: '>>' is necessary, otherwise it will firstly disable all the events.
|
||||
|
||||
To disable an event, echo the event name to the set_event file prefixed
|
||||
with an exclamation point::
|
||||
|
||||
# echo '!sched_wakeup' >> /sys/kernel/debug/tracing/set_event
|
||||
# echo '!sched_wakeup' >> /sys/kernel/tracing/set_event
|
||||
|
||||
To disable all events, echo an empty line to the set_event file::
|
||||
|
||||
# echo > /sys/kernel/debug/tracing/set_event
|
||||
# echo > /sys/kernel/tracing/set_event
|
||||
|
||||
To enable all events, echo ``*:*`` or ``*:`` to the set_event file::
|
||||
|
||||
# echo *:* > /sys/kernel/debug/tracing/set_event
|
||||
# echo *:* > /sys/kernel/tracing/set_event
|
||||
|
||||
The events are organized into subsystems, such as ext4, irq, sched,
|
||||
etc., and a full event name looks like this: <subsystem>:<event>. The
|
||||
@@ -53,29 +53,29 @@ file. All of the events in a subsystem can be specified via the syntax
|
||||
``<subsystem>:*``; for example, to enable all irq events, you can use the
|
||||
command::
|
||||
|
||||
# echo 'irq:*' > /sys/kernel/debug/tracing/set_event
|
||||
# echo 'irq:*' > /sys/kernel/tracing/set_event
|
||||
|
||||
2.2 Via the 'enable' toggle
|
||||
---------------------------
|
||||
|
||||
The events available are also listed in /sys/kernel/debug/tracing/events/ hierarchy
|
||||
The events available are also listed in /sys/kernel/tracing/events/ hierarchy
|
||||
of directories.
|
||||
|
||||
To enable event 'sched_wakeup'::
|
||||
|
||||
# echo 1 > /sys/kernel/debug/tracing/events/sched/sched_wakeup/enable
|
||||
# echo 1 > /sys/kernel/tracing/events/sched/sched_wakeup/enable
|
||||
|
||||
To disable it::
|
||||
|
||||
# echo 0 > /sys/kernel/debug/tracing/events/sched/sched_wakeup/enable
|
||||
# echo 0 > /sys/kernel/tracing/events/sched/sched_wakeup/enable
|
||||
|
||||
To enable all events in sched subsystem::
|
||||
|
||||
# echo 1 > /sys/kernel/debug/tracing/events/sched/enable
|
||||
# echo 1 > /sys/kernel/tracing/events/sched/enable
|
||||
|
||||
To enable all events::
|
||||
|
||||
# echo 1 > /sys/kernel/debug/tracing/events/enable
|
||||
# echo 1 > /sys/kernel/tracing/events/enable
|
||||
|
||||
When reading one of these enable files, there are four results:
|
||||
|
||||
@@ -126,7 +126,7 @@ is the size of the data item, in bytes.
|
||||
For example, here's the information displayed for the 'sched_wakeup'
|
||||
event::
|
||||
|
||||
# cat /sys/kernel/debug/tracing/events/sched/sched_wakeup/format
|
||||
# cat /sys/kernel/tracing/events/sched/sched_wakeup/format
|
||||
|
||||
name: sched_wakeup
|
||||
ID: 60
|
||||
@@ -215,19 +215,19 @@ to the 'filter' file for the given event.
|
||||
|
||||
For example::
|
||||
|
||||
# cd /sys/kernel/debug/tracing/events/sched/sched_wakeup
|
||||
# cd /sys/kernel/tracing/events/sched/sched_wakeup
|
||||
# echo "common_preempt_count > 4" > filter
|
||||
|
||||
A slightly more involved example::
|
||||
|
||||
# cd /sys/kernel/debug/tracing/events/signal/signal_generate
|
||||
# cd /sys/kernel/tracing/events/signal/signal_generate
|
||||
# echo "((sig >= 10 && sig < 15) || sig == 17) && comm != bash" > filter
|
||||
|
||||
If there is an error in the expression, you'll get an 'Invalid
|
||||
argument' error when setting it, and the erroneous string along with
|
||||
an error message can be seen by looking at the filter e.g.::
|
||||
|
||||
# cd /sys/kernel/debug/tracing/events/signal/signal_generate
|
||||
# cd /sys/kernel/tracing/events/signal/signal_generate
|
||||
# echo "((sig >= 10 && sig < 15) || dsig == 17) && comm != bash" > filter
|
||||
-bash: echo: write error: Invalid argument
|
||||
# cat filter
|
||||
@@ -277,7 +277,7 @@ above points:
|
||||
|
||||
Clear the filters on all events in the sched subsystem::
|
||||
|
||||
# cd /sys/kernel/debug/tracing/events/sched
|
||||
# cd /sys/kernel/tracing/events/sched
|
||||
# echo 0 > filter
|
||||
# cat sched_switch/filter
|
||||
none
|
||||
@@ -287,7 +287,7 @@ Clear the filters on all events in the sched subsystem::
|
||||
Set a filter using only common fields for all events in the sched
|
||||
subsystem (all events end up with the same filter)::
|
||||
|
||||
# cd /sys/kernel/debug/tracing/events/sched
|
||||
# cd /sys/kernel/tracing/events/sched
|
||||
# echo common_pid == 0 > filter
|
||||
# cat sched_switch/filter
|
||||
common_pid == 0
|
||||
@@ -298,7 +298,7 @@ Attempt to set a filter using a non-common field for all events in the
|
||||
sched subsystem (all events but those that have a prev_pid field retain
|
||||
their old filters)::
|
||||
|
||||
# cd /sys/kernel/debug/tracing/events/sched
|
||||
# cd /sys/kernel/tracing/events/sched
|
||||
# echo prev_pid == 0 > filter
|
||||
# cat sched_switch/filter
|
||||
prev_pid == 0
|
||||
@@ -313,7 +313,7 @@ exists, will filter all events from tracing any task that does not have the
|
||||
PID listed in the set_event_pid file.
|
||||
::
|
||||
|
||||
# cd /sys/kernel/debug/tracing
|
||||
# cd /sys/kernel/tracing
|
||||
# echo $$ > set_event_pid
|
||||
# echo 1 > events/enable
|
||||
|
||||
@@ -409,14 +409,14 @@ The following commands are supported:
|
||||
specifies that this enablement happens only once::
|
||||
|
||||
# echo 'enable_event:kmem:kmalloc:1' > \
|
||||
/sys/kernel/debug/tracing/events/syscalls/sys_enter_read/trigger
|
||||
/sys/kernel/tracing/events/syscalls/sys_enter_read/trigger
|
||||
|
||||
The following trigger causes kmalloc events to stop being traced
|
||||
when a read system call exits. This disablement happens on every
|
||||
read system call exit::
|
||||
|
||||
# echo 'disable_event:kmem:kmalloc' > \
|
||||
/sys/kernel/debug/tracing/events/syscalls/sys_exit_read/trigger
|
||||
/sys/kernel/tracing/events/syscalls/sys_exit_read/trigger
|
||||
|
||||
The format is::
|
||||
|
||||
@@ -426,10 +426,10 @@ The following commands are supported:
|
||||
To remove the above commands::
|
||||
|
||||
# echo '!enable_event:kmem:kmalloc:1' > \
|
||||
/sys/kernel/debug/tracing/events/syscalls/sys_enter_read/trigger
|
||||
/sys/kernel/tracing/events/syscalls/sys_enter_read/trigger
|
||||
|
||||
# echo '!disable_event:kmem:kmalloc' > \
|
||||
/sys/kernel/debug/tracing/events/syscalls/sys_exit_read/trigger
|
||||
/sys/kernel/tracing/events/syscalls/sys_exit_read/trigger
|
||||
|
||||
Note that there can be any number of enable/disable_event triggers
|
||||
per triggering event, but there can only be one trigger per
|
||||
@@ -448,13 +448,13 @@ The following commands are supported:
|
||||
kmalloc tracepoint is hit::
|
||||
|
||||
# echo 'stacktrace' > \
|
||||
/sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
|
||||
/sys/kernel/tracing/events/kmem/kmalloc/trigger
|
||||
|
||||
The following trigger dumps a stacktrace the first 5 times a kmalloc
|
||||
request happens with a size >= 64K::
|
||||
|
||||
# echo 'stacktrace:5 if bytes_req >= 65536' > \
|
||||
/sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
|
||||
/sys/kernel/tracing/events/kmem/kmalloc/trigger
|
||||
|
||||
The format is::
|
||||
|
||||
@@ -463,16 +463,16 @@ The following commands are supported:
|
||||
To remove the above commands::
|
||||
|
||||
# echo '!stacktrace' > \
|
||||
/sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
|
||||
/sys/kernel/tracing/events/kmem/kmalloc/trigger
|
||||
|
||||
# echo '!stacktrace:5 if bytes_req >= 65536' > \
|
||||
/sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
|
||||
/sys/kernel/tracing/events/kmem/kmalloc/trigger
|
||||
|
||||
The latter can also be removed more simply by the following (without
|
||||
the filter)::
|
||||
|
||||
# echo '!stacktrace:5' > \
|
||||
/sys/kernel/debug/tracing/events/kmem/kmalloc/trigger
|
||||
/sys/kernel/tracing/events/kmem/kmalloc/trigger
|
||||
|
||||
Note that there can be only one stacktrace trigger per triggering
|
||||
event.
|
||||
@@ -488,20 +488,20 @@ The following commands are supported:
|
||||
capture those events when the trigger event occurred::
|
||||
|
||||
# echo 'snapshot if nr_rq > 1' > \
|
||||
/sys/kernel/debug/tracing/events/block/block_unplug/trigger
|
||||
/sys/kernel/tracing/events/block/block_unplug/trigger
|
||||
|
||||
To only snapshot once::
|
||||
|
||||
# echo 'snapshot:1 if nr_rq > 1' > \
|
||||
/sys/kernel/debug/tracing/events/block/block_unplug/trigger
|
||||
/sys/kernel/tracing/events/block/block_unplug/trigger
|
||||
|
||||
To remove the above commands::
|
||||
|
||||
# echo '!snapshot if nr_rq > 1' > \
|
||||
/sys/kernel/debug/tracing/events/block/block_unplug/trigger
|
||||
/sys/kernel/tracing/events/block/block_unplug/trigger
|
||||
|
||||
# echo '!snapshot:1 if nr_rq > 1' > \
|
||||
/sys/kernel/debug/tracing/events/block/block_unplug/trigger
|
||||
/sys/kernel/tracing/events/block/block_unplug/trigger
|
||||
|
||||
Note that there can be only one snapshot trigger per triggering
|
||||
event.
|
||||
@@ -519,20 +519,20 @@ The following commands are supported:
|
||||
trigger event::
|
||||
|
||||
# echo 'traceoff:1 if nr_rq > 1' > \
|
||||
/sys/kernel/debug/tracing/events/block/block_unplug/trigger
|
||||
/sys/kernel/tracing/events/block/block_unplug/trigger
|
||||
|
||||
To always disable tracing when nr_rq > 1::
|
||||
|
||||
# echo 'traceoff if nr_rq > 1' > \
|
||||
/sys/kernel/debug/tracing/events/block/block_unplug/trigger
|
||||
/sys/kernel/tracing/events/block/block_unplug/trigger
|
||||
|
||||
To remove the above commands::
|
||||
|
||||
# echo '!traceoff:1 if nr_rq > 1' > \
|
||||
/sys/kernel/debug/tracing/events/block/block_unplug/trigger
|
||||
/sys/kernel/tracing/events/block/block_unplug/trigger
|
||||
|
||||
# echo '!traceoff if nr_rq > 1' > \
|
||||
/sys/kernel/debug/tracing/events/block/block_unplug/trigger
|
||||
/sys/kernel/tracing/events/block/block_unplug/trigger
|
||||
|
||||
Note that there can be only one traceon or traceoff trigger per
|
||||
triggering event.
|
||||
|
||||
@@ -830,10 +830,10 @@ Error conditions
|
||||
The extended error information and usage takes the form shown in
|
||||
this example::
|
||||
|
||||
# echo xxx > /sys/kernel/debug/tracing/events/sched/sched_wakeup/trigger
|
||||
# echo xxx > /sys/kernel/tracing/events/sched/sched_wakeup/trigger
|
||||
echo: write error: Invalid argument
|
||||
|
||||
# cat /sys/kernel/debug/tracing/error_log
|
||||
# cat /sys/kernel/tracing/error_log
|
||||
[ 5348.887237] location: error: Couldn't yyy: zzz
|
||||
Command: xxx
|
||||
^
|
||||
@@ -843,7 +843,7 @@ Error conditions
|
||||
|
||||
To clear the error log, echo the empty string into it::
|
||||
|
||||
# echo > /sys/kernel/debug/tracing/error_log
|
||||
# echo > /sys/kernel/tracing/error_log
|
||||
|
||||
Examples of using the tracer
|
||||
----------------------------
|
||||
|
||||
@@ -14,7 +14,7 @@ tracing_map.c.
|
||||
Note: All the ftrace histogram command examples assume the working
|
||||
directory is the ftrace /tracing directory. For example::
|
||||
|
||||
# cd /sys/kernel/debug/tracing
|
||||
# cd /sys/kernel/tracing
|
||||
|
||||
Also, the histogram output displayed for those commands will be
|
||||
generally be truncated - only enough to make the point is displayed.
|
||||
@@ -905,7 +905,7 @@ means it will be automatically converted into a field variable::
|
||||
|
||||
# echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0: \
|
||||
onmatch(sched.sched_waking).wakeup_latency($wakeup_lat,next_pid)' >>
|
||||
/sys/kernel/debug/tracing/events/sched/sched_switch/trigger
|
||||
/sys/kernel/tracing/events/sched/sched_switch/trigger
|
||||
|
||||
The diagram for the sched_switch event is similar to previous examples
|
||||
but shows the additional field_vars[] array for hist_data and shows
|
||||
@@ -1112,7 +1112,7 @@ sched_switch event fields, next_pid and next_comm, to generate a
|
||||
wakeup_latency trace event. The next_pid and next_comm event fields
|
||||
are automatically converted into field variables for this purpose::
|
||||
|
||||
# echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0:onmatch(sched.sched_waking).wakeup_latency($wakeup_lat,next_pid,next_comm)' >> /sys/kernel/debug/tracing/events/sched/sched_switch/trigger
|
||||
# echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0:onmatch(sched.sched_waking).wakeup_latency($wakeup_lat,next_pid,next_comm)' >> /sys/kernel/tracing/events/sched/sched_switch/trigger
|
||||
|
||||
The sched_waking hist_debug output shows the same data as in the
|
||||
previous test example::
|
||||
@@ -1305,7 +1305,7 @@ and event name for the onmatch() handler::
|
||||
|
||||
The commands below can be used to clean things up for the next test::
|
||||
|
||||
# echo '!hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0:onmatch(sched.sched_waking).wakeup_latency($wakeup_lat,next_pid,next_comm)' >> /sys/kernel/debug/tracing/events/sched/sched_switch/trigger
|
||||
# echo '!hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0:onmatch(sched.sched_waking).wakeup_latency($wakeup_lat,next_pid,next_comm)' >> /sys/kernel/tracing/events/sched/sched_switch/trigger
|
||||
|
||||
# echo '!hist:keys=pid:ts0=common_timestamp.usecs' >> events/sched/sched_waking/trigger
|
||||
|
||||
@@ -1363,13 +1363,13 @@ with the save() and snapshot() actions. For example::
|
||||
|
||||
# echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0: \
|
||||
onmax($wakeup_lat).save(next_comm,prev_pid,prev_prio,prev_comm)' >>
|
||||
/sys/kernel/debug/tracing/events/sched/sched_switch/trigger
|
||||
/sys/kernel/tracing/events/sched/sched_switch/trigger
|
||||
|
||||
or::
|
||||
|
||||
# echo 'hist:keys=next_pid:wakeup_lat=common_timestamp.usecs-$ts0: \
|
||||
onmax($wakeup_lat).snapshot()' >>
|
||||
/sys/kernel/debug/tracing/events/sched/sched_switch/trigger
|
||||
/sys/kernel/tracing/events/sched/sched_switch/trigger
|
||||
|
||||
save() action field variable test
|
||||
---------------------------------
|
||||
|
||||
File diff suppressed because it is too large
Load Diff
@@ -17,10 +17,10 @@ To enable this feature, build your kernel with CONFIG_KPROBE_EVENTS=y.
|
||||
|
||||
Similar to the event tracer, this doesn't need to be activated via
|
||||
current_tracer. Instead of that, add probe points via
|
||||
/sys/kernel/debug/tracing/kprobe_events, and enable it via
|
||||
/sys/kernel/debug/tracing/events/kprobes/<EVENT>/enable.
|
||||
/sys/kernel/tracing/kprobe_events, and enable it via
|
||||
/sys/kernel/tracing/events/kprobes/<EVENT>/enable.
|
||||
|
||||
You can also use /sys/kernel/debug/tracing/dynamic_events instead of
|
||||
You can also use /sys/kernel/tracing/dynamic_events instead of
|
||||
kprobe_events. That interface will provide unified access to other
|
||||
dynamic events too.
|
||||
|
||||
@@ -153,7 +153,7 @@ trigger:
|
||||
Event Profiling
|
||||
---------------
|
||||
You can check the total number of probe hits and probe miss-hits via
|
||||
/sys/kernel/debug/tracing/kprobe_profile.
|
||||
/sys/kernel/tracing/kprobe_profile.
|
||||
The first column is event name, the second is the number of probe hits,
|
||||
the third is the number of probe miss-hits.
|
||||
|
||||
@@ -177,7 +177,7 @@ Usage examples
|
||||
To add a probe as a new event, write a new definition to kprobe_events
|
||||
as below::
|
||||
|
||||
echo 'p:myprobe do_sys_open dfd=%ax filename=%dx flags=%cx mode=+4($stack)' > /sys/kernel/debug/tracing/kprobe_events
|
||||
echo 'p:myprobe do_sys_open dfd=%ax filename=%dx flags=%cx mode=+4($stack)' > /sys/kernel/tracing/kprobe_events
|
||||
|
||||
This sets a kprobe on the top of do_sys_open() function with recording
|
||||
1st to 4th arguments as "myprobe" event. Note, which register/stack entry is
|
||||
@@ -187,15 +187,15 @@ under tools/perf/).
|
||||
As this example shows, users can choose more familiar names for each arguments.
|
||||
::
|
||||
|
||||
echo 'r:myretprobe do_sys_open $retval' >> /sys/kernel/debug/tracing/kprobe_events
|
||||
echo 'r:myretprobe do_sys_open $retval' >> /sys/kernel/tracing/kprobe_events
|
||||
|
||||
This sets a kretprobe on the return point of do_sys_open() function with
|
||||
recording return value as "myretprobe" event.
|
||||
You can see the format of these events via
|
||||
/sys/kernel/debug/tracing/events/kprobes/<EVENT>/format.
|
||||
/sys/kernel/tracing/events/kprobes/<EVENT>/format.
|
||||
::
|
||||
|
||||
cat /sys/kernel/debug/tracing/events/kprobes/myprobe/format
|
||||
cat /sys/kernel/tracing/events/kprobes/myprobe/format
|
||||
name: myprobe
|
||||
ID: 780
|
||||
format:
|
||||
@@ -218,7 +218,7 @@ You can see the format of these events via
|
||||
You can see that the event has 4 arguments as in the expressions you specified.
|
||||
::
|
||||
|
||||
echo > /sys/kernel/debug/tracing/kprobe_events
|
||||
echo > /sys/kernel/tracing/kprobe_events
|
||||
|
||||
This clears all probe points.
|
||||
|
||||
@@ -233,8 +233,8 @@ Right after definition, each event is disabled by default. For tracing these
|
||||
events, you need to enable it.
|
||||
::
|
||||
|
||||
echo 1 > /sys/kernel/debug/tracing/events/kprobes/myprobe/enable
|
||||
echo 1 > /sys/kernel/debug/tracing/events/kprobes/myretprobe/enable
|
||||
echo 1 > /sys/kernel/tracing/events/kprobes/myprobe/enable
|
||||
echo 1 > /sys/kernel/tracing/events/kprobes/myretprobe/enable
|
||||
|
||||
Use the following command to start tracing in an interval.
|
||||
::
|
||||
@@ -243,10 +243,10 @@ Use the following command to start tracing in an interval.
|
||||
Open something...
|
||||
# echo 0 > tracing_on
|
||||
|
||||
And you can see the traced information via /sys/kernel/debug/tracing/trace.
|
||||
And you can see the traced information via /sys/kernel/tracing/trace.
|
||||
::
|
||||
|
||||
cat /sys/kernel/debug/tracing/trace
|
||||
cat /sys/kernel/tracing/trace
|
||||
# tracer: nop
|
||||
#
|
||||
# TASK-PID CPU# TIMESTAMP FUNCTION
|
||||
|
||||
@@ -36,11 +36,11 @@ Usage Quick Reference
|
||||
::
|
||||
|
||||
$ mount -t debugfs debugfs /sys/kernel/debug
|
||||
$ echo mmiotrace > /sys/kernel/debug/tracing/current_tracer
|
||||
$ cat /sys/kernel/debug/tracing/trace_pipe > mydump.txt &
|
||||
$ echo mmiotrace > /sys/kernel/tracing/current_tracer
|
||||
$ cat /sys/kernel/tracing/trace_pipe > mydump.txt &
|
||||
Start X or whatever.
|
||||
$ echo "X is up" > /sys/kernel/debug/tracing/trace_marker
|
||||
$ echo nop > /sys/kernel/debug/tracing/current_tracer
|
||||
$ echo "X is up" > /sys/kernel/tracing/trace_marker
|
||||
$ echo nop > /sys/kernel/tracing/current_tracer
|
||||
Check for lost events.
|
||||
|
||||
|
||||
@@ -56,11 +56,11 @@ Check that the driver you are about to trace is not loaded.
|
||||
|
||||
Activate mmiotrace (requires root privileges)::
|
||||
|
||||
$ echo mmiotrace > /sys/kernel/debug/tracing/current_tracer
|
||||
$ echo mmiotrace > /sys/kernel/tracing/current_tracer
|
||||
|
||||
Start storing the trace::
|
||||
|
||||
$ cat /sys/kernel/debug/tracing/trace_pipe > mydump.txt &
|
||||
$ cat /sys/kernel/tracing/trace_pipe > mydump.txt &
|
||||
|
||||
The 'cat' process should stay running (sleeping) in the background.
|
||||
|
||||
@@ -68,14 +68,14 @@ Load the driver you want to trace and use it. Mmiotrace will only catch MMIO
|
||||
accesses to areas that are ioremapped while mmiotrace is active.
|
||||
|
||||
During tracing you can place comments (markers) into the trace by
|
||||
$ echo "X is up" > /sys/kernel/debug/tracing/trace_marker
|
||||
$ echo "X is up" > /sys/kernel/tracing/trace_marker
|
||||
This makes it easier to see which part of the (huge) trace corresponds to
|
||||
which action. It is recommended to place descriptive markers about what you
|
||||
do.
|
||||
|
||||
Shut down mmiotrace (requires root privileges)::
|
||||
|
||||
$ echo nop > /sys/kernel/debug/tracing/current_tracer
|
||||
$ echo nop > /sys/kernel/tracing/current_tracer
|
||||
|
||||
The 'cat' process exits. If it does not, kill it by issuing 'fg' command and
|
||||
pressing ctrl+c.
|
||||
@@ -93,12 +93,12 @@ events were lost, the trace is incomplete. You should enlarge the buffers and
|
||||
try again. Buffers are enlarged by first seeing how large the current buffers
|
||||
are::
|
||||
|
||||
$ cat /sys/kernel/debug/tracing/buffer_size_kb
|
||||
$ cat /sys/kernel/tracing/buffer_size_kb
|
||||
|
||||
gives you a number. Approximately double this number and write it back, for
|
||||
instance::
|
||||
|
||||
$ echo 128000 > /sys/kernel/debug/tracing/buffer_size_kb
|
||||
$ echo 128000 > /sys/kernel/tracing/buffer_size_kb
|
||||
|
||||
Then start again from the top.
|
||||
|
||||
|
||||
@@ -4,7 +4,7 @@
|
||||
# to extract some high-level information on what is going on. The accuracy of the parser
|
||||
# may vary considerably
|
||||
#
|
||||
# Example usage: trace-pagealloc-postprocess.pl < /sys/kernel/debug/tracing/trace_pipe
|
||||
# Example usage: trace-pagealloc-postprocess.pl < /sys/kernel/tracing/trace_pipe
|
||||
# other options
|
||||
# --prepend-parent Report on the parent proc and PID
|
||||
# --read-procstat If the trace lacks process info, get it from /proc
|
||||
@@ -94,7 +94,7 @@ sub generate_traceevent_regex {
|
||||
my $regex;
|
||||
|
||||
# Read the event format or use the default
|
||||
if (!open (FORMAT, "/sys/kernel/debug/tracing/events/$event/format")) {
|
||||
if (!open (FORMAT, "/sys/kernel/tracing/events/$event/format")) {
|
||||
$regex = $default;
|
||||
} else {
|
||||
my $line;
|
||||
|
||||
@@ -3,7 +3,7 @@
|
||||
# page reclaim. It makes an attempt to extract some high-level information on
|
||||
# what is going on. The accuracy of the parser may vary
|
||||
#
|
||||
# Example usage: trace-vmscan-postprocess.pl < /sys/kernel/debug/tracing/trace_pipe
|
||||
# Example usage: trace-vmscan-postprocess.pl < /sys/kernel/tracing/trace_pipe
|
||||
# other options
|
||||
# --read-procstat If the trace lacks process info, get it from /proc
|
||||
# --ignore-pid Aggregate processes of the same name together
|
||||
@@ -140,7 +140,7 @@ sub generate_traceevent_regex {
|
||||
my $regex;
|
||||
|
||||
# Read the event format or use the default
|
||||
if (!open (FORMAT, "/sys/kernel/debug/tracing/events/$event/format")) {
|
||||
if (!open (FORMAT, "/sys/kernel/tracing/events/$event/format")) {
|
||||
print("WARNING: Event $event format string not found\n");
|
||||
return $default;
|
||||
} else {
|
||||
|
||||
@@ -26,10 +26,10 @@ assumed that the PCL tool tools/perf has been installed and is in your path.
|
||||
2.1 Standard Utilities
|
||||
----------------------
|
||||
|
||||
All possible events are visible from /sys/kernel/debug/tracing/events. Simply
|
||||
All possible events are visible from /sys/kernel/tracing/events. Simply
|
||||
calling::
|
||||
|
||||
$ find /sys/kernel/debug/tracing/events -type d
|
||||
$ find /sys/kernel/tracing/events -type d
|
||||
|
||||
will give a fair indication of the number of events available.
|
||||
|
||||
@@ -59,7 +59,7 @@ See Documentation/trace/events.rst for a proper description on how events
|
||||
can be enabled system-wide. A short example of enabling all events related
|
||||
to page allocation would look something like::
|
||||
|
||||
$ for i in `find /sys/kernel/debug/tracing/events -name "enable" | grep mm_`; do echo 1 > $i; done
|
||||
$ for i in `find /sys/kernel/tracing/events -name "enable" | grep mm_`; do echo 1 > $i; done
|
||||
|
||||
3.2 System-Wide Event Enabling with SystemTap
|
||||
---------------------------------------------
|
||||
@@ -189,7 +189,7 @@ time on a system-wide basis using -a and sleep.
|
||||
============================================
|
||||
|
||||
When events are enabled the events that are triggering can be read from
|
||||
/sys/kernel/debug/tracing/trace_pipe in human-readable format although binary
|
||||
/sys/kernel/tracing/trace_pipe in human-readable format although binary
|
||||
options exist as well. By post-processing the output, further information can
|
||||
be gathered on-line as appropriate. Examples of post-processing might include
|
||||
|
||||
|
||||
@@ -12,13 +12,13 @@ To enable this feature, build your kernel with CONFIG_UPROBE_EVENTS=y.
|
||||
|
||||
Similar to the kprobe-event tracer, this doesn't need to be activated via
|
||||
current_tracer. Instead of that, add probe points via
|
||||
/sys/kernel/debug/tracing/uprobe_events, and enable it via
|
||||
/sys/kernel/debug/tracing/events/uprobes/<EVENT>/enable.
|
||||
/sys/kernel/tracing/uprobe_events, and enable it via
|
||||
/sys/kernel/tracing/events/uprobes/<EVENT>/enable.
|
||||
|
||||
However unlike kprobe-event tracer, the uprobe event interface expects the
|
||||
user to calculate the offset of the probepoint in the object.
|
||||
|
||||
You can also use /sys/kernel/debug/tracing/dynamic_events instead of
|
||||
You can also use /sys/kernel/tracing/dynamic_events instead of
|
||||
uprobe_events. That interface will provide unified access to other
|
||||
dynamic events too.
|
||||
|
||||
@@ -79,7 +79,7 @@ For $comm, the default type is "string"; any other type is invalid.
|
||||
Event Profiling
|
||||
---------------
|
||||
You can check the total number of probe hits per event via
|
||||
/sys/kernel/debug/tracing/uprobe_profile. The first column is the filename,
|
||||
/sys/kernel/tracing/uprobe_profile. The first column is the filename,
|
||||
the second is the event name, the third is the number of probe hits.
|
||||
|
||||
Usage examples
|
||||
@@ -87,28 +87,28 @@ Usage examples
|
||||
* Add a probe as a new uprobe event, write a new definition to uprobe_events
|
||||
as below (sets a uprobe at an offset of 0x4245c0 in the executable /bin/bash)::
|
||||
|
||||
echo 'p /bin/bash:0x4245c0' > /sys/kernel/debug/tracing/uprobe_events
|
||||
echo 'p /bin/bash:0x4245c0' > /sys/kernel/tracing/uprobe_events
|
||||
|
||||
* Add a probe as a new uretprobe event::
|
||||
|
||||
echo 'r /bin/bash:0x4245c0' > /sys/kernel/debug/tracing/uprobe_events
|
||||
echo 'r /bin/bash:0x4245c0' > /sys/kernel/tracing/uprobe_events
|
||||
|
||||
* Unset registered event::
|
||||
|
||||
echo '-:p_bash_0x4245c0' >> /sys/kernel/debug/tracing/uprobe_events
|
||||
echo '-:p_bash_0x4245c0' >> /sys/kernel/tracing/uprobe_events
|
||||
|
||||
* Print out the events that are registered::
|
||||
|
||||
cat /sys/kernel/debug/tracing/uprobe_events
|
||||
cat /sys/kernel/tracing/uprobe_events
|
||||
|
||||
* Clear all events::
|
||||
|
||||
echo > /sys/kernel/debug/tracing/uprobe_events
|
||||
echo > /sys/kernel/tracing/uprobe_events
|
||||
|
||||
Following example shows how to dump the instruction pointer and %ax register
|
||||
at the probed text address. Probe zfree function in /bin/zsh::
|
||||
|
||||
# cd /sys/kernel/debug/tracing/
|
||||
# cd /sys/kernel/tracing/
|
||||
# cat /proc/`pgrep zsh`/maps | grep /bin/zsh | grep r-xp
|
||||
00400000-0048a000 r-xp 00000000 08:03 130904 /bin/zsh
|
||||
# objdump -T /bin/zsh | grep -w zfree
|
||||
@@ -168,7 +168,7 @@ Also, you can disable the event by::
|
||||
|
||||
# echo 0 > events/uprobes/enable
|
||||
|
||||
And you can see the traced information via /sys/kernel/debug/tracing/trace.
|
||||
And you can see the traced information via /sys/kernel/tracing/trace.
|
||||
::
|
||||
|
||||
# cat trace
|
||||
|
||||
@@ -11,10 +11,10 @@ that can be viewed via existing tools, such as ftrace and perf.
|
||||
To enable this feature, build your kernel with CONFIG_USER_EVENTS=y.
|
||||
|
||||
Programs can view status of the events via
|
||||
/sys/kernel/debug/tracing/user_events_status and can both register and write
|
||||
data out via /sys/kernel/debug/tracing/user_events_data.
|
||||
/sys/kernel/tracing/user_events_status and can both register and write
|
||||
data out via /sys/kernel/tracing/user_events_data.
|
||||
|
||||
Programs can also use /sys/kernel/debug/tracing/dynamic_events to register and
|
||||
Programs can also use /sys/kernel/tracing/dynamic_events to register and
|
||||
delete user based events via the u: prefix. The format of the command to
|
||||
dynamic_events is the same as the ioctl with the u: prefix applied.
|
||||
|
||||
@@ -22,9 +22,9 @@ Typically programs will register a set of events that they wish to expose to
|
||||
tools that can read trace_events (such as ftrace and perf). The registration
|
||||
process gives back two ints to the program for each event. The first int is
|
||||
the status bit. This describes which bit in little-endian format in the
|
||||
/sys/kernel/debug/tracing/user_events_status file represents this event. The
|
||||
/sys/kernel/tracing/user_events_status file represents this event. The
|
||||
second int is the write index which describes the data when a write() or
|
||||
writev() is called on the /sys/kernel/debug/tracing/user_events_data file.
|
||||
writev() is called on the /sys/kernel/tracing/user_events_data file.
|
||||
|
||||
The structures referenced in this document are contained within the
|
||||
/include/uapi/linux/user_events.h file in the source tree.
|
||||
@@ -35,7 +35,7 @@ filesystem and may be mounted at different paths than above.*
|
||||
Registering
|
||||
-----------
|
||||
Registering within a user process is done via ioctl() out to the
|
||||
/sys/kernel/debug/tracing/user_events_data file. The command to issue is
|
||||
/sys/kernel/tracing/user_events_data file. The command to issue is
|
||||
DIAG_IOCSREG.
|
||||
|
||||
This command takes a packed struct user_reg as an argument::
|
||||
@@ -54,7 +54,7 @@ and the write index.
|
||||
|
||||
User based events show up under tracefs like any other event under the
|
||||
subsystem named "user_events". This means tools that wish to attach to the
|
||||
events need to use /sys/kernel/debug/tracing/events/user_events/[name]/enable
|
||||
events need to use /sys/kernel/tracing/events/user_events/[name]/enable
|
||||
or perf record -e user_events:[name] when attaching/recording.
|
||||
|
||||
**NOTE:** *The write_index returned is only valid for the FD that was used*
|
||||
@@ -96,7 +96,7 @@ Would be represented by the following field::
|
||||
Deleting
|
||||
-----------
|
||||
Deleting an event from within a user process is done via ioctl() out to the
|
||||
/sys/kernel/debug/tracing/user_events_data file. The command to issue is
|
||||
/sys/kernel/tracing/user_events_data file. The command to issue is
|
||||
DIAG_IOCSDEL.
|
||||
|
||||
This command only requires a single string specifying the event to delete by
|
||||
@@ -110,7 +110,7 @@ When tools attach/record user based events the status of the event is updated
|
||||
in realtime. This allows user programs to only incur the cost of the write() or
|
||||
writev() calls when something is actively attached to the event.
|
||||
|
||||
User programs call mmap() on /sys/kernel/debug/tracing/user_events_status to
|
||||
User programs call mmap() on /sys/kernel/tracing/user_events_status to
|
||||
check the status for each event that is registered. The bit to check in the
|
||||
file is given back after the register ioctl() via user_reg.status_bit. The bit
|
||||
is always in little-endian format. Programs can check if the bit is set either
|
||||
|
||||
Some files were not shown because too many files have changed in this diff Show More
Reference in New Issue
Block a user