Pull perf/urgent fixes from Arnaldo Carvalho de Melo:
- Fix occasional decoding errors when tracing system-wide with
Intel PT (Adrian Hunter)
- Fix ip compression in Intel PT for some specific packet types not
present on current hardware (Adrian Hunter)
- Fix annotation of objects with debuginfo files (Anton Blanchard)
- Fix build on Fedora Rawhide (25) wrt using the right header to
get the major() & minor() definitions in the jitdump code, now
it is deprecated getting those using sys/types.h, one has to use
sys/sysmacros.h (Arnaldo Carvalho de Melo)
- Sync arm64/s390 kvm related header files (Arnaldo Carvalho de Melo)
- Check for dup and fdopen failures in 'perf probe' (Colin Ian King,
Arnaldo Carvalho de Melo)
- Fix showing callchains in pipe mode, i.e.
perf record -g -o - workload | perf script
now shows callchains (He Kuang)
- Show proper message when the scripts directory points to some
invalid location in 'perf script --list' (He Kuang)
- Fix 'perf mem -t store' to record 'cpu/mem-stores/P' events
again (Jiri Olsa)
- Fix ppc64le build failure when libelf is not present (Ravi Bangoria)
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
In order to successfully decode Intel PT traces, context switch events
are needed from the moment the trace starts. Currently that is ensured
by using the 'immediate' flag which enables the switch event when it is
opened.
However, since commit 86c2786994 ("perf intel-pt: Add support for
PERF_RECORD_SWITCH") that might not always happen. When tracing
system-wide the context switch event is added to the tracking event
which was not set as 'immediate'. Change that so it is.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: stable@vger.kernel.org # v4.4+
Fixes: 86c2786994 ("perf intel-pt: Add support for PERF_RECORD_SWITCH")
Link: http://lkml.kernel.org/r/1471245784-22580-1-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Commit 73cdf0c6ea ("perf symbols: Record text offset in dso
to calculate objdump address") started storing the offset of
the text section for all DSOs:
if (elf_section_by_name(elf, &ehdr, &tshdr, ".text", NULL))
dso->text_offset = tshdr.sh_addr - tshdr.sh_offset;
Unfortunately this breaks debuginfo files, because we need to calculate
the offset of the text section in the associated executable file. As a
result perf annotate returns junk for all debuginfo files.
Fix this by using runtime_ss->elf which should point at the executable
when parsing a debuginfo file.
Signed-off-by: Anton Blanchard <anton@samba.org>
Reviewed-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Tested-by: Wang Nan <wangnan0@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Cc: stable@vger.kernel.org # v4.6+
Fixes: 73cdf0c6ea ("perf symbols: Record text offset in dso to calculate objdump address")
Link: http://lkml.kernel.org/r/20160813115533.6de17912@kryten
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Because perf data from pipe do not have a header with evsel attr, we
should not check that and disable symbol_conf.use_callchain. Otherwise,
perf script won't show callchains even if the data stream contains
callchain.
Before:
$ perf record -g -o - uname |perf script
Linux
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.000 MB - ]
uname 1828 182630.186578: 250000 cpu-clock: ..b9499 setup_arg_pages
uname 1828 182630.186850: 250000 cpu-clock: ..83b20 ___might_sleep
uname 1828 182630.187153: 250000 cpu-clock: ..4b6be file_map_prot_ch
...
After:
$ perf record -g -o - uname |perf script
Linux
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.000 MB - ]
uname 1833 182675.927099: 250000 cpu-clock:
ba5520 _raw_spin_lock+0xfe200040 ([kernel.kallsyms])
389dd4 expand_downwards+0xfe200154 ([kernel.kallsyms])
389f34 expand_stack+0xfe200024 ([kernel.kallsyms])
3b957e setup_arg_pages+0xfe20019e ([kernel.kallsyms])
40c80f load_elf_binary+0xfe20042f ([kernel.kallsyms])
...
Signed-off-by: He Kuang <hekuang@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1470309943-153909-2-git-send-email-hekuang@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Perf shows the usage message when perf scripts folder failed to open,
which misleads users to let them think the command is being mistyped.
This patch shows a proper message and guides users to check the
PERF_EXEC_PATH environment variable in that case.
Before:
$ perf script --list
Usage: perf script [<options>]
or: perf script [<options>] record <script> [<record-options>] <command>
or: perf script [<options>] report <script> [script-args]
or: perf script [<options>] <script> [<record-options>] <command>
or: perf script [<options>] <top-script> [script-args]
-l, --list list available scripts
After:
$ perf script --list
open(/home/user/perf-core/scripts) failed.
Check for "PERF_EXEC_PATH" env to set scripts dir.
Signed-off-by: He Kuang <hekuang@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1470309943-153909-1-git-send-email-hekuang@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Noticed on Fedora Rawhide:
$ gcc --version
gcc (GCC) 6.1.1 20160721 (Red Hat 6.1.1-4)
$ rpm -q glibc
glibc-2.24.90-1.fc26.x86_64
$
CC /tmp/build/perf/util/jitdump.o
util/jitdump.c: In function 'jit_repipe_code_load':
util/jitdump.c:428:2: error: '__major_from_sys_types' is deprecated:
In the GNU C Library, `major' is defined by <sys/sysmacros.h>.
For historical compatibility, it is currently defined by
<sys/types.h> as well, but we plan to remove this soon.
To use `major', include <sys/sysmacros.h> directly.
If you did not intend to use a system-defined macro `major',
you should #undef it after including <sys/types.h>.
[-Werror=deprecated-declarations]
event->mmap2.maj = major(st.st_dev);
^~~~~
In file included from /usr/include/features.h:397:0,
from /usr/include/sys/types.h:25,
from util/jitdump.c:1:
/usr/include/sys/sysmacros.h:87:1: note: declared here
__SYSMACROS_DEFINE_MAJOR (__SYSMACROS_FST_IMPL_TEMPL)
Fix it following that recomendation.
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-3majvd0adhfr25rvx4v5e9te@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Pull perf fixes from Ingo Molnar:
"Mostly tooling fixes, plus two uncore-PMU fixes, an uprobes fix, a
perf-cgroups fix and an AUX events fix"
* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
perf/x86/intel/uncore: Add enable_box for client MSR uncore
perf/x86/intel/uncore: Fix uncore num_counters
uprobes/x86: Fix RIP-relative handling of EVEX-encoded instructions
perf/core: Set cgroup in CPU contexts for new cgroup events
perf/core: Fix sideband list-iteration vs. event ordering NULL pointer deference crash
perf probe ppc64le: Fix probe location when using DWARF
perf probe: Add function to post process kernel trace events
tools: Sync cpufeatures headers with the kernel
toops: Sync tools/include/uapi/linux/bpf.h with the kernel
tools: Sync cpufeatures.h and vmx.h with the kernel
perf probe: Support signedness casting
perf stat: Avoid skew when reading events
perf probe: Fix module name matching
perf probe: Adjust map->reloc offset when finding kernel symbol from map
perf hists: Trim libtraceevent trace_seq buffers
perf script: Add 'bpf-output' field to usage message
Pull libnvdimm fixes from Dan Williams:
- Fix for the nd_blk (NVDIMM Block Window Aperture) driver.
A spec clarification requires the driver to mask off reserved bits in
status register. This is tagged for -stable back to the v4.2 kernel.
- Fix for a kernel crash in the nvdimm unit tests when module loading
is interrupted with SIGTERM. Tagged for -stable since validation
efforts external to Intel use the unit tests for qualifying
backports.
- Add a new 'size' sysfs attribute for the BTT (NVDIMM Block
Translation Table) driver to make it symmetric with the other
namespace personality drivers (PFN and DAX) that provide a size
attribute for indicating how much namespace capacity is lost to
metadata.
The BTT change arrived at the start of the merge window and has
appeared in a -next release. It can technically wait for 4.9, but it
is small, fixes asymmetry in the libnvdimm-sysfs interface, and
something I would have squeezed into the v4.8 pull request had it
arrived a few days earlier.
* 'libnvdimm-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/nvdimm/nvdimm:
tools/testing/nvdimm: fix SIGTERM vs hotplug crash
nvdimm, btt: add a size attribute for BTTs
libnvdimm, nd_blk: mask off reserved status bits
Michael reported 'perf mem -t store record' being broken. The reason is
latest rework of this area:
commit acbe613e0c ("perf tools: Add monitored events array")
We don't mark perf_mem_events store record when -t store option is
specified.
Committer notes:
Before:
# perf mem -t store record usleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.020 MB perf.data (7 samples) ]
# perf evlist
cycles:ppp
#
After:
# perf mem -t store record usleep 1
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.020 MB perf.data (7 samples) ]
# perf evlist
cpu/mem-stores/P
#
Reported-by: Michael Petlan <mpetlan@redhat.com>
Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Fixes: acbe613e0c ("perf tools: Add monitored events array")
Link: http://lkml.kernel.org/r/1470905457-18311-1-git-send-email-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The June 2015 Intel SDM introduced IP Compression types 4 and 6. Refer
to section 36.4.2.2 Target IP (TIP) Packet - IP Compression.
Existing Intel PT packet decoder did not support type 4, and got type 6
wrong. Because type 3 and type 4 have the same number of bytes, the
packet 'count' has been changed from being the number of ip bytes to
being the type code. That allows the Intel PT decoder to correctly
decide whether to sign-extend or use the last ip. However that also
meant the code had to be adjusted in a number of places.
Currently hardware is not using the new compression types, so this fix
has no effect on existing hardware.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/1469005206-3049-1-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The unit tests crash when hotplug races the previous probe. This race
requires that the loading of the nfit_test module be terminated with
SIGTERM, and the module to be unloaded while the ars scan is still
running.
In contrast to the normal nfit driver, the unit test calls
acpi_nfit_init() twice to simulate hotplug, whereas the nominal case
goes through the acpi_nfit_notify() event handler. The
acpi_nfit_notify() path is careful to flush the previous region
registration before servicing the hotplug event. The unit test was
missing this guarantee.
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: [<ffffffff810cdce7>] pwq_activate_delayed_work+0x47/0x170
[..]
Call Trace:
[<ffffffff810ce186>] pwq_dec_nr_in_flight+0x66/0xa0
[<ffffffff810ce490>] process_one_work+0x2d0/0x680
[<ffffffff810ce331>] ? process_one_work+0x171/0x680
[<ffffffff810ce88e>] worker_thread+0x4e/0x480
[<ffffffff810ce840>] ? process_one_work+0x680/0x680
[<ffffffff810ce840>] ? process_one_work+0x680/0x680
[<ffffffff810d5343>] kthread+0xf3/0x110
[<ffffffff8199846f>] ret_from_fork+0x1f/0x40
[<ffffffff810d5250>] ? kthread_create_on_node+0x230/0x230
Cc: <stable@vger.kernel.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
We have some tests that assume we're using std=gnu99, which is fine on
most compilers, but some old compilers use a different default.
So make it explicit that we want to use std=gnu99.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Pull perf/urgent fixes from Arnaldo Carvalho de Melo:
User visible fixes:
- Fix the lookup for a kernel module in 'perf probe', fixing for instance, the
erroneous return of "[raid10]" when looking for "[raid1]" (Konstantin Khlebnikov)
- Disable counters in a group before reading them in 'perf stat', to avoid skew (Mark Rutland)
- Fix adding probes to function aliases in systems using kaslr (Masami Hiramatsu)
- Trip libtraceevent trace_seq buffers, removing unnecessary memory usage that could
bring a system using tracepoint events with 'perf top' to a crawl, as the trace_seq
buffers start at a whooping 4 KB, which is very rarely used in perf's usecases,
so realloc it to the really used space as a last measure after using libtraceevent
functions to format the fields of tracepoint events (Arnaldo Carvalho de Melo)
- Fix 'perf probe' location when using DWARF on ppc64le (Ravi Bangoria)
- Allow specifying signedness casts to a 'perf probe' variable, to shorten
the number of steps to see signed values that otherwise would always appear
as hex values (Naohiro Aota)
Documentation fixes:
- Add 'bpf-output' field to 'perf script' usage message (Brendan Gregg)
Infrastructure fixes:
- Sync kernel header files: cpufeatures.h, {disabled,required}-features.h,
bpf.h and vmx.h, so that we get a clean build, without warnings about files
being different from the kernel counterparts.
A verification of the need or desirability of changes in tools/ based on what
was done in the kernel changesets was made and documented in the respective
file sync changesets (Arnaldo Carvalho de Melo)
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Powerpc has Global Entry Point and Local Entry Point for functions. LEP
catches call from both the GEP and the LEP. Symbol table of ELF contains
GEP and Offset from which we can calculate LEP, but debuginfo does not
have LEP info.
Currently, perf prioritize symbol table over dwarf to probe on LEP for
ppc64le. But when user tries to probe with function parameter, we fall
back to using dwarf(i.e. GEP) and when function called via LEP, probe
will never hit.
For example:
$ objdump -d vmlinux
...
do_sys_open():
c0000000002eb4a0: e8 00 4c 3c addis r2,r12,232
c0000000002eb4a4: 60 00 42 38 addi r2,r2,96
c0000000002eb4a8: a6 02 08 7c mflr r0
c0000000002eb4ac: d0 ff 41 fb std r26,-48(r1)
$ sudo ./perf probe do_sys_open
$ sudo cat /sys/kernel/debug/tracing/kprobe_events
p:probe/do_sys_open _text+3060904
$ sudo ./perf probe 'do_sys_open filename:string'
$ sudo cat /sys/kernel/debug/tracing/kprobe_events
p:probe/do_sys_open _text+3060896 filename_string=+0(%gpr4):string
For second case, perf probed on GEP. So when function will be called via
LEP, probe won't hit.
$ sudo ./perf record -a -e probe:do_sys_open ls
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.195 MB perf.data ]
To resolve this issue, let's not prioritize symbol table, let perf
decide what it wants to use. Perf is already converting GEP to LEP when
it uses symbol table. When perf uses debuginfo, let it find LEP offset
form symbol table. This way we fall back to probe on LEP for all cases.
After patch:
$ sudo ./perf probe 'do_sys_open filename:string'
$ sudo cat /sys/kernel/debug/tracing/kprobe_events
p:probe/do_sys_open _text+3060904 filename_string=+0(%gpr4):string
$ sudo ./perf record -a -e probe:do_sys_open ls
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.197 MB perf.data (11 samples) ]
Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.vnet.ibm.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1470723805-5081-2-git-send-email-ravi.bangoria@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Due to:
1e61f78baf ("x86/cpufeature: Make sure DISABLED/REQUIRED macros are updated")
No changes to tools using those headers (tools/arch/x86/lib/mem{set,cpu}_64.S)
seems necessary.
Detected by the tools build header drift checker:
$ make -C tools/perf O=/tmp/build/perf
make: Entering directory '/home/acme/git/linux/tools/perf'
BUILD: Doing 'make -j4' parallel build
GEN /tmp/build/perf/common-cmds.h
Warning: tools/arch/x86/include/asm/disabled-features.h differs from kernel
Warning: tools/arch/x86/include/asm/required-features.h differs from kernel
Warning: tools/arch/x86/include/asm/cpufeatures.h differs from kernel
CC /tmp/build/perf/util/probe-finder.o
CC /tmp/build/perf/builtin-help.o
<SNIP>
^C$
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-ja75m7zk8j0jkzmrv16i5ehw@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The way we're using kernel headers in tools/ now, with a copy that is
made to the same path prefixed by "tools/" plus checking if that copy
got stale, i.e. if the kernel counterpart changed, helps in keeping
track with new features that may be useful for tools to exploit.
For instance, looking at all the changes to bpf.h since it was last
copied to tools/include brings this to toolers' attention:
Need to investigate this one to check how to run a program via perf, setting up
a BPF event, that will take advantage of the way perf already calls clang/LLVM,
sets up the event and runs the workload in a single command line, helping in
debugging such semi cooperative programs:
96ae522795 ("bpf: Add bpf_probe_write_user BPF helper to be called in tracers")
This one needs further investigation about using the feature it improves
in 'perf trace' to do some tcpdumpin' mixed with syscalls, tracepoints,
probe points, callgraphs, etc:
555c8a8623 ("bpf: avoid stack copy and use skb ctx for event output")
Add tracing just packets that are related to some container to that mix:
4a482f34af ("cgroup: bpf: Add bpf_skb_in_cgroup_proto")
4ed8ec521e ("cgroup: bpf: Add BPF_MAP_TYPE_CGROUP_ARRAY")
Definetely needs to have example programs accessing task_struct from a bpf proggie
started from 'perf trace':
606274c5ab ("bpf: introduce bpf_get_current_task() helper")
Core networking related, XDP:
6ce96ca348 ("bpf: add XDP_TX xdp_action for direct forwarding")
6a773a15a1 ("bpf: add XDP prog type for early driver filter")
13c5c240f7 ("bpf: add bpf_get_hash_recalc helper")
d2485c4242 ("bpf: add bpf_skb_change_type helper")
6578171a7f ("bpf: add bpf_skb_change_proto helper")
Changes detected by the tools build system:
$ make -C tools/perf O=/tmp/build/perf install-bin
make: Entering directory '/home/acme/git/linux/tools/perf'
BUILD: Doing 'make -j4' parallel build
Warning: tools/include/uapi/linux/bpf.h differs from kernel
INSTALL GTK UI
CC /tmp/build/perf/bench/mem-memcpy-x86-64-asm.o
<SNIP>
$
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@fb.com>
Cc: Brenden Blanco <bblanco@plumgrid.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David Ahern <dsahern@gmail.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Sargun Dhillon <sargun@sargun.me>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-difq4ts1xvww6eyfs9e7zlft@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
There were changes related to the deprecation of the "pcommit"
instruction:
fd1d961dd6 ("x86/insn: remove pcommit")
dfa169bbee ("Revert "KVM: x86: add pcommit support"")
No need to update anything in the tools, as "pcommit" wasn't being
listed on the VMX_EXIT_REASONS in the tools/perf/arch/x86/util/kvm-stat.c
file.
Just grab fresh copies of these files to silence the file cache
coherency detector:
$ make -C tools/perf O=/tmp/build/perf install-bin
make: Entering directory '/home/acme/git/linux/tools/perf'
BUILD: Doing 'make -j4' parallel build
Warning: tools/arch/x86/include/asm/cpufeatures.h differs from kernel
Warning: tools/arch/x86/include/uapi/asm/vmx.h differs from kernel
INSTALL GTK UI
<SNIP>
#
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Wang Nan <wangnan0@huawei.com>
Cc: Xiao Guangrong <guangrong.xiao@linux.intel.com>
Link: http://lkml.kernel.org/n/tip-07pmcc1ysydhyyxbmp1vt0l4@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
The 'perf probe' tool detects a variable's type and use the detected
type to add a new probe. Then, kprobes prints its variable in
hexadecimal format if the variable is unsigned and prints in decimal if
it is signed.
We sometimes want to see unsigned variable in decimal format (i.e.
sector_t or size_t). In that case, we need to investigate the variable's
size manually to specify just signedness.
This patch add signedness casting support. By specifying "s" or "u" as a
type, perf-probe will investigate variable size as usual and use the
specified signedness.
E.g. without this:
$ perf probe -a 'submit_bio bio->bi_iter.bi_sector'
Added new event:
probe:submit_bio (on submit_bio with bi_sector=bio->bi_iter.bi_sector)
You can now use it in all perf tools, such as:
perf record -e probe:submit_bio -aR sleep 1
$ cat trace_pipe|head
dbench-9692 [003] d..1 971.096633: submit_bio: (submit_bio+0x0/0x140) bi_sector=0x3a3d00
dbench-9692 [003] d..1 971.096685: submit_bio: (submit_bio+0x0/0x140) bi_sector=0x1a3d80
dbench-9692 [003] d..1 971.096687: submit_bio: (submit_bio+0x0/0x140) bi_sector=0x3a3d80
...
// need to investigate the variable size
$ perf probe -a 'submit_bio bio->bi_iter.bi_sector:s64'
Added new event:
probe:submit_bio (on submit_bio with bi_sector=bio->bi_iter.bi_sector:s64)
You can now use it in all perf tools, such as:
perf record -e probe:submit_bio -aR sleep 1
With this:
// just use "s" to cast its signedness
$ perf probe -v -a 'submit_bio bio->bi_iter.bi_sector:s'
Added new event:
probe:submit_bio (on submit_bio with bi_sector=bio->bi_iter.bi_sector:s)
You can now use it in all perf tools, such as:
perf record -e probe:submit_bio -aR sleep 1
$ cat trace_pipe|head
dbench-9689 [001] d..1 1212.391237: submit_bio: (submit_bio+0x0/0x140) bi_sector=128
dbench-9689 [001] d..1 1212.391252: submit_bio: (submit_bio+0x0/0x140) bi_sector=131072
dbench-9697 [006] d..1 1212.398611: submit_bio: (submit_bio+0x0/0x140) bi_sector=30208
This commit also update perf-probe.txt to describe "types". Most parts
are based on existing documentation: Documentation/trace/kprobetrace.txt
Committer note:
Testing using 'perf trace':
# perf probe -a 'submit_bio bio->bi_iter.bi_sector'
Added new event:
probe:submit_bio (on submit_bio with bi_sector=bio->bi_iter.bi_sector)
You can now use it in all perf tools, such as:
perf record -e probe:submit_bio -aR sleep 1
# trace --no-syscalls --ev probe:submit_bio
0.000 probe:submit_bio:(ffffffffac3aee00) bi_sector=0xc133c0)
3181.861 probe:submit_bio:(ffffffffac3aee00) bi_sector=0x6cffb8)
3181.881 probe:submit_bio:(ffffffffac3aee00) bi_sector=0x6cffc0)
3184.488 probe:submit_bio:(ffffffffac3aee00) bi_sector=0x6cffc8)
<SNIP>
4717.927 probe:submit_bio:(ffffffffac3aee00) bi_sector=0x4dc7a88)
4717.970 probe:submit_bio:(ffffffffac3aee00) bi_sector=0x4dc7880)
^C[root@jouet ~]#
Now, using this new feature:
[root@jouet ~]# perf probe -a 'submit_bio bio->bi_iter.bi_sector:s'
Added new event:
probe:submit_bio (on submit_bio with bi_sector=bio->bi_iter.bi_sector:s)
You can now use it in all perf tools, such as:
perf record -e probe:submit_bio -aR sleep 1
[root@jouet ~]# trace --no-syscalls --ev probe:submit_bio
0.000 probe:submit_bio:(ffffffffac3aee00) bi_sector=7145704)
0.017 probe:submit_bio:(ffffffffac3aee00) bi_sector=7145712)
0.019 probe:submit_bio:(ffffffffac3aee00) bi_sector=7145720)
2.567 probe:submit_bio:(ffffffffac3aee00) bi_sector=7145728)
5631.919 probe:submit_bio:(ffffffffac3aee00) bi_sector=0)
5631.941 probe:submit_bio:(ffffffffac3aee00) bi_sector=8)
5631.945 probe:submit_bio:(ffffffffac3aee00) bi_sector=16)
5631.948 probe:submit_bio:(ffffffffac3aee00) bi_sector=24)
^C#
With callchains:
# trace --no-syscalls --ev probe:submit_bio/max-stack=10/
0.000 probe:submit_bio:(ffffffffac3aee00) bi_sector=50662544)
submit_bio+0xa8200001 ([kernel.kallsyms])
submit_bh+0xa8200013 ([kernel.kallsyms])
jbd2_journal_commit_transaction+0xa8200691 ([kernel.kallsyms])
kjournald2+0xa82000ca ([kernel.kallsyms])
kthread+0xa82000d8 ([kernel.kallsyms])
ret_from_fork+0xa820001f ([kernel.kallsyms])
0.023 probe:submit_bio:(ffffffffac3aee00) bi_sector=50662552)
submit_bio+0xa8200001 ([kernel.kallsyms])
submit_bh+0xa8200013 ([kernel.kallsyms])
jbd2_journal_commit_transaction+0xa8200691 ([kernel.kallsyms])
kjournald2+0xa82000ca ([kernel.kallsyms])
kthread+0xa82000d8 ([kernel.kallsyms])
ret_from_fork+0xa820001f ([kernel.kallsyms])
0.027 probe:submit_bio:(ffffffffac3aee00) bi_sector=50662560)
submit_bio+0xa8200001 ([kernel.kallsyms])
submit_bh+0xa8200013 ([kernel.kallsyms])
jbd2_journal_commit_transaction+0xa8200691 ([kernel.kallsyms])
kjournald2+0xa82000ca ([kernel.kallsyms])
kthread+0xa82000d8 ([kernel.kallsyms])
ret_from_fork+0xa820001f ([kernel.kallsyms])
2.593 probe:submit_bio:(ffffffffac3aee00) bi_sector=50662568)
submit_bio+0xa8200001 ([kernel.kallsyms])
submit_bh+0xa8200013 ([kernel.kallsyms])
journal_submit_commit_record+0xa82001ac ([kernel.kallsyms])
jbd2_journal_commit_transaction+0xa82012e8 ([kernel.kallsyms])
kjournald2+0xa82000ca ([kernel.kallsyms])
kthread+0xa82000d8 ([kernel.kallsyms])
ret_from_fork+0xa820001f ([kernel.kallsyms])
^C#
Signed-off-by: Naohiro Aota <naohiro.aota@hgst.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1470710408-23515-1-git-send-email-naohiro.aota@hgst.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
When we don't have a tracee (i.e. we're attaching to a task or CPU),
counters can still be running after our workload finishes, and can still
be running as we read their values. As we read events one-by-one, there
can be arbitrary skew between values of events, even within a group.
This means that ratios within an event group are not reliable.
This skew can be seen if measuring a group of identical events, e.g:
# perf stat -a -C0 -e '{cycles,cycles}' sleep 1
To avoid this, we must stop groups from counting before we read the
values of any constituent events. This patch adds and makes use of a new
disable_counters() helper, which disables group leaders (and thus each
group as a whole). This mirrors the use of enable_counters() for
starting event groups in the absence of a tracee.
Closing a group leader splits the group, and without a disabled group
leader the newly split events will begin counting. Thus to ensure counts
are reliable we must defer closing group leaders until all counts have
been read. To do so this patch removes the event closing logic from the
read_counters() helper, explicitly closes the events using
perf_evlist__close(), which also aids legibility.
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1470747869-3567-1-git-send-email-mark.rutland@arm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Milian Wolff
Ingo Molnar
Adrian Hunter
Arnaldo Carvalho de Melo
Colin Ian King
Anton Blanchard
He Kuang
Linus Torvalds
Ravi Bangoria
Jiri Olsa
Dan Williams
Michael Ellerman
Naohiro Aota
Mark Rutland