From: Arnaldo Carvalho de Melo Date: Fri, 27 Feb 2015 22:52:10 +0000 (-0300) Subject: perf tools: Fix FORK after COMM when synthesizing records for pre-existing threads X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=4aa5f4f7bb8bc41cba15bcd0d80c4fb085027d6b;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git perf tools: Fix FORK after COMM when synthesizing records for pre-existing threads In this commit: commit 363b785f3805a2632eb09a8b430842461c21a640 Author: Don Zickus Date: Fri Mar 14 10:43:44 2014 -0400 perf tools: Speed up thread map generation We ended up emitting PERF_RECORD_FORK events after their corresponding PERF_RECORD_COMM, so the code below will remove the "existing thread" and then recreates it, unnecessarily: [root@ssdandy ~]# perf probe -x ~/bin/perf -L machine__process_fork_event 0 int machine__process_fork_event(struct machine *machine, union perf_event *event, struct perf_sample *sample) 2 { 3 struct thread *thread = machine__find_thread(machine, event->fork.pid, event->fork.tid); 6 struct thread *parent = machine__findnew_thread(machine, event->fork.ppid, event->fork.ptid); /* if a thread currently exists for the thread id remove it */ if (thread != NULL) 12 machine__remove_thread(machine, thread); 14 thread = machine__findnew_thread(machine, event->fork.pid, event->fork.tid); 16 if (dump_trace) 17 perf_event__fprintf_task(event, stdout); 19 if (thread == NULL || parent == NULL || 20 thread__fork(thread, parent, sample->time) < 0) { 21 dump_printf("problem processing PERF_RECORD_FORK, skipping event.\n"); 22 return -1; } 25 return 0; 26 } [root@ssdandy ~]# perf probe -x ~/bin/perf fork_after_comm=machine__process_fork_event:12 Added new event: probe_perf:fork_after_comm (on machine__process_fork_event:12 in /home/acme/bin/perf) You can now use it in all perf tools, such as: perf record -e probe_perf:fork_after_comm -aR sleep 1 [root@ssdandy ~]# [root@ssdandy ~]# perf record -g -e probe_perf:* trace -o /tmp/bla ^C[ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.021 MB perf.data (30 samples) ] Terminated [root@ssdandy ~]# [root@ssdandy ~]# perf report --no-children --show-total-period --stdio # To display the perf.data header info, please use --header/--header-only options. # # Samples: 30 of event 'probe_perf:fork_after_comm' # Event count (approx.): 30 # # Overhead Period Command Shared Object Symbol # ........ ............ ....... ............. ............................... # 100.00% 30 trace trace [.] machine__process_fork_event | ---machine__process_fork_event __event__synthesize_thread.part.2 perf_event__synthesize_threads cmd_trace main __libc_start_main [root@ssdandy ~]# And Looking at 'perf report -D' output we see it: 0 0 0x8698 [0x30]: PERF_RECORD_COMM: auditd:703/707 0 0 0x86c8 [0x38]: PERF_RECORD_FORK(703:707):(703:703) Fix it by more closely mimicking how the kernel generates those records when a new fork happens, i.e. first a PERF_RECORD_FORK, then a PERF_RECORD_COMM. Cc: Adrian Hunter Cc: Borislav Petkov Cc: David Ahern Cc: Don Zickus Cc: Frederic Weisbecker Cc: Jiri Olsa Cc: Namhyung Kim Cc: Stephane Eranian Link: http://lkml.kernel.org/n/tip-h0emvymi2t3mw8dlqd6d6z73@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c index 9e806d855b04..d5efa5092ce6 100644 --- a/tools/perf/util/event.c +++ b/tools/perf/util/event.c @@ -95,9 +95,7 @@ static pid_t perf_event__get_comm_tgid(pid_t pid, char *comm, size_t len) return tgid; } -static pid_t perf_event__synthesize_comm(struct perf_tool *tool, - union perf_event *event, pid_t pid, - perf_event__handler_t process, +static pid_t perf_event__prepare_comm(union perf_event *event, pid_t pid, struct machine *machine) { size_t size; @@ -124,6 +122,19 @@ static pid_t perf_event__synthesize_comm(struct perf_tool *tool, (sizeof(event->comm.comm) - size) + machine->id_hdr_size); event->comm.tid = pid; +out: + return tgid; +} + +static pid_t perf_event__synthesize_comm(struct perf_tool *tool, + union perf_event *event, pid_t pid, + perf_event__handler_t process, + struct machine *machine) +{ + pid_t tgid = perf_event__prepare_comm(event, pid, machine); + + if (tgid == -1) + goto out; if (process(tool, event, &synth_sample, machine) != 0) return -1; @@ -139,7 +150,6 @@ static int perf_event__synthesize_fork(struct perf_tool *tool, { memset(&event->fork, 0, sizeof(event->fork) + machine->id_hdr_size); - /* this is really a clone event but we use fork to synthesize it */ event->fork.ppid = tgid; event->fork.ptid = tgid; event->fork.pid = tgid; @@ -368,19 +378,23 @@ static int __event__synthesize_thread(union perf_event *comm_event, if (*end) continue; - tgid = perf_event__synthesize_comm(tool, comm_event, _pid, - process, machine); + tgid = perf_event__prepare_comm(comm_event, _pid, machine); if (tgid == -1) return -1; + if (perf_event__synthesize_fork(tool, fork_event, _pid, tgid, + process, machine) < 0) + return -1; + /* + * Send the prepared comm event + */ + if (process(tool, comm_event, &synth_sample, machine) != 0) + return -1; + if (_pid == pid) { /* process the parent's maps too */ rc = perf_event__synthesize_mmap_events(tool, mmap_event, pid, tgid, process, machine, mmap_data); - } else { - /* only fork the tid's map, to save time */ - rc = perf_event__synthesize_fork(tool, fork_event, _pid, tgid, - process, machine); } if (rc)