mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2025-01-22 10:13:16 +07:00
236a3bbd5c
Occassionally events (e.g., context-switch, sched tracepoints) are losing
the conversion of sample data associated with a thread. For example:
$ perf record -e sched:sched_switch -c 1 -a -- sleep 5
$ perf script
<selected events shown>
ls 30482 [000] 1379727.583037: sched:sched_switch: prev_comm=ls prev_pid=30482 ...
ls 30482 [000] 1379727.586339: sched:sched_switch: prev_comm=ls prev_pid=30482 ...
:30482 30482 [000] 1379727.589462: sched:sched_switch: prev_comm=ls prev_pid=30482 ...
The last line lost the conversion from tid to comm. If you look at the events
(perf script -D) you see why - a SAMPLE event is generated after the EXIT:
0 1379727589449774 0x1540b0 [0x38]: PERF_RECORD_EXIT(30482:30482):(30482:30482)
0 1379727589462497 0x1540e8 [0x80]: PERF_RECORD_SAMPLE(IP, 1): 30482/30482: 0xffffffff816416f1 period: 1 addr: 0
... thread: :30482:30482
When perf processes the EXIT event the thread is moved to the dead_threads
list. When the SAMPLE event is processed no thread exists for the pid so a new
one is created by machine__findnew_thread.
This patch address the problem by delaying the move to the dead_threads list
until the tid is re-used (per Adrian's suggestion).
With this patch we get the previous example shows:
ls 30482 [000] 1379727.583037: sched:sched_switch: prev_comm=ls prev_pid=30482 ...
ls 30482 [000] 1379727.586339: sched:sched_switch: prev_comm=ls prev_pid=30482 ...
ls 30482 [000] 1379727.589462: sched:sched_switch: prev_comm=ls prev_pid=30482 ...
and
0 1379727589449774 0x1540b0 [0x38]: PERF_RECORD_EXIT(30482:30482):(30482:30482)
0 1379727589462497 0x1540e8 [0x80]: PERF_RECORD_SAMPLE(IP, 1): 30482/30482: 0xffffffff816416f1 period: 1 addr: 0
... thread: ls:30482
v4: per Arnaldo's request add dead flag to thread struct and set when task exits
v3: re-do from a time based check to a delayed move to dead_threads list
v2: Rebased to latest perf/core branch. Changed time comparison to use
a macro which explicitly shows the time basis
Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: Adrian Hunter <adrian.hunter@intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1376491767-84171-1-git-send-email-dsahern@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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| .. | ||
| include | ||
| scripting-engines | ||
| abspath.c | ||
| alias.c | ||
| annotate.c | ||
| annotate.h | ||
| bitmap.c | ||
| build-id.c | ||
| build-id.h | ||
| cache.h | ||
| callchain.c | ||
| callchain.h | ||
| cgroup.c | ||
| cgroup.h | ||
| color.c | ||
| color.h | ||
| config.c | ||
| cpumap.c | ||
| cpumap.h | ||
| ctype.c | ||
| debug.c | ||
| debug.h | ||
| dso.c | ||
| dso.h | ||
| dwarf-aux.c | ||
| dwarf-aux.h | ||
| environment.c | ||
| event.c | ||
| event.h | ||
| evlist.c | ||
| evlist.h | ||
| evsel.c | ||
| evsel.h | ||
| exec_cmd.c | ||
| exec_cmd.h | ||
| generate-cmdlist.sh | ||
| header.c | ||
| header.h | ||
| help.c | ||
| help.h | ||
| hist.c | ||
| hist.h | ||
| hweight.c | ||
| intlist.c | ||
| intlist.h | ||
| levenshtein.c | ||
| levenshtein.h | ||
| machine.c | ||
| machine.h | ||
| map.c | ||
| map.h | ||
| pager.c | ||
| parse-events.c | ||
| parse-events.h | ||
| parse-events.l | ||
| parse-events.y | ||
| parse-options.c | ||
| parse-options.h | ||
| path.c | ||
| perf_regs.h | ||
| PERF-VERSION-GEN | ||
| pmu.c | ||
| pmu.h | ||
| pmu.l | ||
| pmu.y | ||
| probe-event.c | ||
| probe-event.h | ||
| probe-finder.c | ||
| probe-finder.h | ||
| pstack.c | ||
| pstack.h | ||
| python-ext-sources | ||
| python.c | ||
| quote.c | ||
| quote.h | ||
| rblist.c | ||
| rblist.h | ||
| run-command.c | ||
| run-command.h | ||
| session.c | ||
| session.h | ||
| setup.py | ||
| sigchain.c | ||
| sigchain.h | ||
| sort.c | ||
| sort.h | ||
| stat.c | ||
| stat.h | ||
| strbuf.c | ||
| strbuf.h | ||
| strfilter.c | ||
| strfilter.h | ||
| string.c | ||
| strlist.c | ||
| strlist.h | ||
| svghelper.c | ||
| svghelper.h | ||
| symbol-elf.c | ||
| symbol-minimal.c | ||
| symbol.c | ||
| symbol.h | ||
| sysfs.c | ||
| sysfs.h | ||
| target.c | ||
| target.h | ||
| thread_map.c | ||
| thread_map.h | ||
| thread.c | ||
| thread.h | ||
| tool.h | ||
| top.c | ||
| top.h | ||
| trace-event-info.c | ||
| trace-event-parse.c | ||
| trace-event-read.c | ||
| trace-event-scripting.c | ||
| trace-event.h | ||
| types.h | ||
| unwind.c | ||
| unwind.h | ||
| usage.c | ||
| util.c | ||
| util.h | ||
| values.c | ||
| values.h | ||
| vdso.c | ||
| vdso.h | ||
| wrapper.c | ||
| xyarray.c | ||
| xyarray.h | ||