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Adrian Hunter fc18380fb9 perf script: Display negative tid in non-sample events 
The kernel can release tasks while they are still running. This can
result in a task having no tid, in which case perf records a tid of -1.
Improve the perf script output in that case.

Example:

Before:

  # cat ./autoreap.c

  #include <sys/types.h>
  #include <unistd.h>
  #include <sys/wait.h>
  #include <signal.h>

  struct sigaction act = {
          .sa_handler = SIG_IGN,
  };

  int main()
  {
          pid_t child;
          int status = 0;

          sigaction(SIGCHLD, &act, NULL);
          child = fork();
          if (child == 0)
                  return 123;
          wait(&status);
          return 0;
  }

  # gcc -o autoreap autoreap.c
  # ./perf record -a -e dummy --switch-events ./autoreap
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.948 MB perf.data ]
  # ./perf script --show-task-events --show-switch-events | grep -C2 'autoreap\|4294967295\|-1'
           swapper     0 [004] 18462.673613: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt  next pid/tid: 25189/25189
              perf 25189 [004] 18462.673614: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid:     0/0
          autoreap 25189 [004] 18462.673800: PERF_RECORD_COMM exec: autoreap:25189/25189
          autoreap 25189 [004] 18462.674042: PERF_RECORD_FORK(25191:25191):(25189:25189)
          autoreap 25189 [004] 18462.674050: PERF_RECORD_SWITCH_CPU_WIDE OUT          next pid/tid:     0/0
           swapper     0 [004] 18462.674051: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid: 25189/25189
           swapper     0 [005] 18462.674083: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt  next pid/tid: 25191/25191
          autoreap 25191 [005] 18462.674084: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid:     0/0
           swapper     0 [003] 18462.674121: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt  next pid/tid:    11/11
       rcu_preempt    11 [003] 18462.674121: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid:     0/0
       rcu_preempt    11 [003] 18462.674124: PERF_RECORD_SWITCH_CPU_WIDE OUT          next pid/tid:     0/0
           swapper     0 [003] 18462.674124: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid:    11/11
          autoreap 25191 [005] 18462.674138: PERF_RECORD_EXIT(25191:25191):(25189:25189)
  PERF_RECORD_SWITCH_CPU_WIDE OUT          next pid/tid:     0/0
           swapper     0 [005] 18462.674149: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid: 4294967295/4294967295
           swapper     0 [004] 18462.674182: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt  next pid/tid: 25189/25189
          autoreap 25189 [004] 18462.674183: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid:     0/0
          autoreap 25189 [004] 18462.674218: PERF_RECORD_EXIT(25189:25189):(25188:25188)
          autoreap 25189 [004] 18462.674225: PERF_RECORD_SWITCH_CPU_WIDE OUT          next pid/tid:     0/0
           swapper     0 [004] 18462.674226: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid: 25189/25189
           swapper     0 [007] 18462.674257: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt  next pid/tid: 25188/25188

After:

  # ./perf script --show-task-events --show-switch-events | grep -C2 'autoreap\|4294967295\|-1'
           swapper     0 [004] 18462.673613: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt  next pid/tid: 25189/25189
              perf 25189 [004] 18462.673614: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid:     0/0
          autoreap 25189 [004] 18462.673800: PERF_RECORD_COMM exec: autoreap:25189/25189
          autoreap 25189 [004] 18462.674042: PERF_RECORD_FORK(25191:25191):(25189:25189)
          autoreap 25189 [004] 18462.674050: PERF_RECORD_SWITCH_CPU_WIDE OUT          next pid/tid:     0/0
           swapper     0 [004] 18462.674051: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid: 25189/25189
           swapper     0 [005] 18462.674083: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt  next pid/tid: 25191/25191
          autoreap 25191 [005] 18462.674084: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid:     0/0
           swapper     0 [003] 18462.674121: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt  next pid/tid:    11/11
       rcu_preempt    11 [003] 18462.674121: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid:     0/0
       rcu_preempt    11 [003] 18462.674124: PERF_RECORD_SWITCH_CPU_WIDE OUT          next pid/tid:     0/0
           swapper     0 [003] 18462.674124: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid:    11/11
          autoreap 25191 [005] 18462.674138: PERF_RECORD_EXIT(25191:25191):(25189:25189)
               :-1    -1 [005] 18462.674149: PERF_RECORD_SWITCH_CPU_WIDE OUT          next pid/tid:     0/0
           swapper     0 [005] 18462.674149: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid:    -1/-1
           swapper     0 [004] 18462.674182: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt  next pid/tid: 25189/25189
          autoreap 25189 [004] 18462.674183: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid:     0/0
          autoreap 25189 [004] 18462.674218: PERF_RECORD_EXIT(25189:25189):(25188:25188)
          autoreap 25189 [004] 18462.674225: PERF_RECORD_SWITCH_CPU_WIDE OUT          next pid/tid:     0/0
           swapper     0 [004] 18462.674226: PERF_RECORD_SWITCH_CPU_WIDE IN           prev pid/tid: 25189/25189
           swapper     0 [007] 18462.674257: PERF_RECORD_SWITCH_CPU_WIDE OUT preempt  next pid/tid: 25188/25188

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lore.kernel.org/lkml/20200909084923.9096-2-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-09-17 16:06:22 -03:00
..
accounting SPDX patches for 5.7-rc1. 2020-04-03 13:12:26 -07:00
arch tools headers kvm s390: Sync headers with the kernel sources 2020-08-12 08:52:32 -03:00
bootconfig tools/bootconfig: Add testcases for value override operator 2020-08-03 16:22:29 -04:00
bpf tools/resolve_btfids: Fix sections with wrong alignment 2020-08-20 14:17:20 -07:00
build tools feature: Add missing -lzstd to the fast path feature detection 2020-09-09 11:11:01 -03:00
cgroup tools/cgroup: add memcg_slabinfo.py tool 2020-08-07 11:33:25 -07:00
debugging
edid
firewire
firmware
gpio tools: gpio: fix spurious close warning in gpio-event-mon 2020-07-12 10:22:01 +02:00
hv tools: hv: change http to https in hv_kvp_daemon.c 2020-07-06 10:46:23 +00:00
iio
include tools headers UAPI: update linux/in.h copy 2020-09-14 19:06:41 -03:00
io_uring io_uring: change the poll type to be 32-bits 2020-06-21 20:44:00 -06:00
kvm/kvm_stat tools/kvm_stat: add sample systemd unit file 2020-04-21 09:13:12 -04:00
laptop change email address for Pali Rohár 2020-04-10 15:36:22 -07:00
leds
lib libtraceevent: Fix build warning on 32-bit arches 2020-09-03 15:45:15 -03:00
memory-model These were the main changes in this cycle: 2020-08-03 14:39:35 -07:00
nfsd
objtool Misc updates: 2020-08-03 14:45:33 -07:00
pci
pcmcia
perf perf script: Display negative tid in non-sample events 2020-09-17 16:06:22 -03:00
power ACPI updates for 5.9-rc1 2020-08-03 20:37:22 -07:00
scripts
spi spi: tools: Make default_tx/rx and input_tx static 2020-06-11 16:27:24 +01:00
testing linux-kselftest-5.9-rc5 2020-09-08 11:56:47 -07:00
thermal/tmon - Convert tsens configuration DT binding to yaml (Rajeshwari) 2020-04-07 20:00:16 -07:00
time
usb tools: usb: move to tools buildsystem 2020-08-19 14:11:44 +02:00
virtio virtio: fixes, features 2020-08-11 14:34:17 -07:00
vm tools/vm/page_owner_sort.c: filter out unneeded line 2020-06-03 20:09:49 -07:00
wmi
Makefile bpf: Compile resolve_btfids tool at kernel compilation start 2020-07-13 10:42:02 -07:00