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0b687912c9
The purpose of this test is to test for races in the exit of 'perf
trace' missing the last events, it was failing when the COMM wasn't
resolved either because we missed some PERF_RECORD_COMM or somehow
raced on getting it from procfs.
Add --no-comm to the 'perf trace' command line so that we get a
consistent, pid only output, which allows the test to achieve its goal.
This is the output from
'perf trace --no-comm -e syscalls:sys_enter_exit_group':
0.000 21953 syscalls:sys_enter_exit_group()
0.000 21955 syscalls:sys_enter_exit_group()
0.000 21957 syscalls:sys_enter_exit_group()
0.000 21959 syscalls:sys_enter_exit_group()
0.000 21961 syscalls:sys_enter_exit_group()
0.000 21963 syscalls:sys_enter_exit_group()
0.000 21965 syscalls:sys_enter_exit_group()
0.000 21967 syscalls:sys_enter_exit_group()
0.000 21969 syscalls:sys_enter_exit_group()
0.000 21971 syscalls:sys_enter_exit_group()
Now it passes:
root@number:~# perf test "trace exit race"
110: perf trace exit race : Ok
root@number:~#
root@number:~# perf test -v "trace exit race"
110: perf trace exit race : Ok
root@number:~#
If we artificially make it run just 9 times instead of the 10 it runs,
i.e. by manually doing:
trace_shutdown_race() {
for _ in $(seq 9); do
that 9 is $iter, 10 in the patch, we get:
root@number:~# vim ~acme/libexec/perf-core/tests/shell/trace_exit_race.sh
root@number:~# perf test -v "trace exit race"
--- start ---
test child forked, pid 24629
Missing output, expected 10 but only got 9
---- end(-1) ----
110: perf trace exit race : FAILED!
root@number:~#
I.e. 9 'perf trace' calls produced the expected output, the inverse grep
didn't show anything, so the patch provided by Howard for the previous
patch kicks in and shows a more informative message.
Tested-by: Howard Chu <howardchu95@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Benjamin Peterson <benjamin@engflow.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/lkml/ZzdknoHqrJbojb6P@x1
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.