This is a partial revert of commit
7f1b588f20 ("trace: emit name <-> ID
mapping in simpletrace header"), which broke the SystemTap flight
recorder because event mapping records may not be present in the ring
buffer when the trace is analyzed. This means simpletrace.py
--no-header does not know the event ID mapping needed to pretty-print
the trace.
Instead of numbering events dynamically, use a static event ID mapping
as dictated by the event order in the trace-events-all file.
The simpletrace.py script also uses trace-events-all so the next patch
will fix the simpletrace.py --no-header option to take advantage of this
knowledge.
Cc: Daniel P. Berrange <berrange@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170815084430.7128-2-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
QEMU keeps track of trace event enabled/disabled state and provides
monitor commands to inspect and modify the "dstate". SystemTap and
LTTng UST maintain independent enabled/disabled states for each trace
event, the other backends rely on QEMU dstate.
Introduce a new per-event macro that combines backend-specific dstate
like this:
#define TRACE_MY_EVENT_BACKEND_DSTATE() ( \
QEMU_MY_EVENT_ENABLED() || /* SystemTap */ \
tracepoint_enabled(qemu, my_event) /* LTTng UST */ || \
false)
This will be used to extend trace_event_get_state() in the next patch.
[Daniel Berrange pointed out that QEMU_MY_EVENT_ENABLED() must be true
by default, not false. This way events will fire even if the DTrace
implementation does not implement the SystemTap semaphores feature.
Ubuntu Precise uses lttng-ust-dev 2.0.2 which does not have
tracepoint_enabled(), so we need a compatibility wrapper to keep Travis
builds passing.
--Stefan]
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20170731140718.22010-2-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
fixup! trace: add TRACE_<event>_BACKEND_DSTATE()
The simpletrace compatibility code for systemtap creates a
function and some global variables for mapping to event ID
numbers. We generate multiple -simpletrace.stp files though,
one per target and systemtap considers functions & variables
to be globally scoped, not per file. So if trying to use the
simpletrace compat probes, systemtap will complain:
# stap -e 'probe qemu.system.arm.simpletrace.visit_type_str { print( "hello")}'
semantic error: conflicting global variables: identifier 'event_name_to_id_map' at /usr/share/systemtap/tapset/qemu-aarch64-simpletrace.stp:3:8
source: global event_name_to_id_map
^
identifier 'event_name_to_id_map' at /usr/share/systemtap/tapset/qemu-system-arm-simpletrace.stp:3:8
source: global event_name_to_id_map
^
WARNING: cross-file global variable reference to identifier 'event_name_to_id_map' at /usr/share/systemtap/tapset/qemu-system-arm-simpletrace.stp:3:8 from: identifier 'event_name_to_id_map' at /usr/share/systemtap/tapset/qemu-aarch64-simpletrace.stp:8:21
source: if (!([name] in event_name_to_id_map)) {
^
WARNING: cross-file global variable reference to identifier 'event_next_id' at /usr/share/systemtap/tapset/qemu-system-arm-simpletrace.stp:4:8 from: identifier 'event_next_id' at :9:38
source: event_name_to_id_map[name] = event_next_id
^
We already have a string used to prefix probe names, so just
replace '.' with '_' to get a function / variable name prefix
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170728133657.5525-1-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
If an event is dynamically disabled, the TCG code that calls the
execution-time tracer is not generated.
Removes the overheads of execution-time tracers for dynamically disabled
events. As a bonus, also avoids checking the event state when the
execution-time tracer is called from TCG-generated code (since otherwise
TCG would simply not call it).
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-id: 149915799921.6295.13067154430923434035.stgit@frigg.lan
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Commit 0ab8ed18a6 ("trace: switch to
modular code generation for sub-directories") forgot to convert "tcg"
trace events to the modular code generation approach where each
sub-directory has its own trace-events file.
This patch fixes compilation for "tcg" trace events. Currently they are
only used in the root ./trace-events file.
"tcg" trace events can only be used in the root ./trace-events file for
the time being.
Reported-by: Peter Maydell <peter.maydell@linaro.org>
Tested-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-id: 20170327131718.18268-1-stefanha@redhat.com
Suggested-by: Emilio G. Cota <cota@braap.org>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Introduce rules in the top level Makefile that are able to generate
trace.[ch] files in every subdirectory which has a trace-events file.
The top level directory is handled specially, so instead of creating
trace.h, it creates trace-root.h. This allows sub-directories to
include the top level trace-root.h file, without ambiguity wrt to
the trace.g file in the current sub-dir.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170125161417.31949-7-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The declarations in the generated-tracers.h file are
assuming there's only ever going to be one instance
of this header, as they are not namespaced. When we
have one header per event group, if a single source
file needs to include multiple sets of trace events,
the symbols will all clash.
This change thus introduces a '--group NAME' arg to the
'tracetool' program. This will cause all the symbols in
the generated header files to be given a unique namespace.
If no group is given, the group name 'common' is used,
which is suitable for the current usage where there is
only one global trace-events file used for code generation.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Reviewed-by: Lluís Vilanova <vilanova@ac.upc.edu>
Message-id: 1475588159-30598-21-git-send-email-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Currently the generated-events.[ch] files contain the
event dstates, constants and TraceEvent structs, while the
generated-tracers.[ch] files contain the actual trace
probe logic. With the removal of usage of the event enums
from the API there is no longer any compelling reason for
the separation between these files. The generated-events.h
content is only ever needed from the generated-tracers.[ch]
files.
The enums/constants/structs from generated-events.[ch] are
thus moved into the generated-tracers.[ch], so that there
is one less file to be generated.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 1475588159-30598-17-git-send-email-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Instead of having the code generator assign event IDs and
event VCPU IDs, assign them when the events are registered
at runtime. This will allow code to be generated from
individual trace-events without having to figure out
globally unique numbering at build time.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 1475588159-30598-16-git-send-email-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Remove the notion of there being a single global array
of trace events, by introducing a method for registering
groups of events.
The module_call_init() needs to be invoked at the start
of any program that wants to make use of the trace
support. Currently this covers system emulators qemu-nbd,
qemu-img and qemu-io.
[Squashed the following fix from Daniel P. Berrange
<berrange@redhat.com>:
linux-user/bsd-user: initialize trace events subsystem
The bsd-user/linux-user programs make use of the CPU emulation
code and this now requires that the trace events subsystem
is enabled, otherwise it'll crash trying to allocate an empty
trace events bitmap for the CPU object.
--Stefan]
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 1475588159-30598-14-git-send-email-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Currently simpletrace assumes that events are given IDs
starting from 0, based on the order in which they appear
in the trace-events file, with no gaps. When the
trace-events file is split up, this assumption becomes
problematic.
To deal with this, extend the simpletrace format so that
it outputs a table of event name <-> ID mappings. That
will allow QEMU to assign arbitrary IDs to events without
breaking simpletrace parsing.
The v3 simple trace format was
FILE HEADER
EVENT TRACE RECORD 0
EVENT TRACE RECORD 1
...
EVENT TRACE RECORD N
The v4 simple trace format is now
FILE HEADER
EVENT MAPPING RECORD 0
EVENT MAPPING RECORD 1
...
EVENT MAPPING RECORD M
EVENT TRACE RECORD RECORD 0
EVENT TRACE RECORD RECORD 1
...
EVENT TRACE RECORD N
Although this shows all the mapping records being emitted
upfront, this is not required by the format. While the main
simpletrace backend will emit all mappings at startup,
the systemtap simpletrace.stp script will emit the mappings
at first use. eg
FILE HEADER
...
EVENT MAPPING RECORD 0
EVENT TRACE RECORD RECORD 0
EVENT TRACE RECORD RECORD 1
EVENT MAPPING RECORD 1
EVENT TRACE RECORD RECORD 2
...
EVENT TRACE RECORD N
This is more space efficient given that most trace records
only include a subset of events.
In modifying the systemtap simpletrace code, a 'begin' probe
was added to emit the trace event header, so you no longer
need to add '--no-header' when running simpletrace.py for
systemtap generated trace files.
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 1475588159-30598-12-git-send-email-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The TraceEventID and TraceEventVCPUID enums constants are
no longer actually used for anything critical.
The TRACE_EVENT_COUNT limit is used to determine the size
of the TraceEvents array, and can be removed if we just
NULL terminate the array instead.
The TRACE_VCPU_EVENT_COUNT limit is used as a magic value
for marking non-vCPU events, and also for declaring the
size of the trace dstate mask in the CPUState struct.
The former usage can be replaced by a dedicated constant
TRACE_EVENT_VCPU_NONE, defined as (uint32_t)-1. For the
latter usage, we can simply define a constant for the
number of VCPUs, avoiding the need for the full enum.
The only other usages of the enum values can be replaced
by accesing the id/vcpu_id fields via the named TraceEvent
structs.
Reviewed-by: Lluís Vilanova <vilanova@ac.upc.edu>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 1475588159-30598-11-git-send-email-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Instead of having a global dstate array, declare a single
'uint16 TRACE_${EVENT_NAME}_DSTATE' variable for each
trace event. Record a pointer to this variable in the
TraceEvent struct too.
By turning trace_event_get_state_dynamic_by_id into a
macro, this still hits the fast path, and cache affinity
is ensured by declaring all the uint16 vars adjacent to
each other.
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 1475588159-30598-7-git-send-email-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Events with the 'vcpu' property are conditionally emitted according to
their per-vCPU state. Other events are emitted normally based on their
global tracing state.
Note that the per-vCPU condition check applies to all tracing backends.
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
A new event attribute 'cpu_id' is added to have a separate ID
space ('TRACE_VCPU_*') for all events with the 'vcpu' property.
These are later used to identify which events are enabled on each vCPU.
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Manually drop redundant includes that scripts/clean-includes misses,
e.g. because they're hidden in generator programs, or they use the
wrong kind of delimiter.
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This property identifies events that trace vCPU-specific information.
It adds a "CPUState*" argument to events with the property, identifying
the vCPU raising the event. TCG translation events also have a
"TCGv_env" implicit argument that is later used as the "CPUState*"
argument at execution time.
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Message-id: 145641861797.30295.6991314023181842105.stgit@localhost
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The current code forces the use of a chain of ".original" dereferences,
which looks odd.
Signed-off-by: Lluís Vilanova <vilanova@ac.upc.edu>
Message-id: 145641858988.30295.7223459456488075843.stgit@localhost
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Include qemu/osdep.h as the first include in generated .c files,
so they don't implicitly rely on some other included header
to pull it in.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Eric Blake <eblake@redhat.com>
This is more cache friendly on the fast path, where we already have
the event id available.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
DTrace on Mac OS X fails due to trace events using 'self' as an argument
name:
GEN trace/generated-tracers-dtrace.h
dtrace: failed to compile script trace/generated-tracers-dtrace.dtrace: line 1330: syntax error, unexpected DT_KEY_SELF, expecting ) near "self"
make: *** [trace/generated-tracers-dtrace.h] Error 1
Filter argument names according to the list of DTrace .d file reserved
keywords.
Note that DTrace on Mac and Linux still do not work after this patch.
There are additional build issues remaining.
Reported-by: Henk Poley <henkpoley@gmail.com>
Tested-by: Henk Poley <henkpoley@gmail.com>
Cc: Lluís Vilanova <vilanova@ac.upc.edu>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
