Commit a9c5e6c1 authored Oct 22, 2018 by Arnaldo Carvalho de Melo

perf trace: Introduce per-event maximum number of events property

Call it 'nr', as in this context it should be expressive enough, i.e.:

  # perf trace -e sched:*waking/nr=8,call-graph=fp/
     0.000 :0/0 sched:sched_waking:comm=rcu_sched pid=10 prio=120 target_cpu=001
                                       try_to_wake_up ([kernel.kallsyms])
                                       sched_clock ([kernel.kallsyms])
     3.933 :0/0 sched:sched_waking:comm=rcu_sched pid=10 prio=120 target_cpu=001
                                       try_to_wake_up ([kernel.kallsyms])
                                       sched_clock ([kernel.kallsyms])
     3.970 IPDL Backgroun/3622 sched:sched_waking:comm=Gecko_IOThread pid=3569 prio=120 target_cpu=003
                                       try_to_wake_up ([kernel.kallsyms])
                                       __libc_write (/usr/lib64/libpthread-2.26.so)
    20.069 IPDL Backgroun/3622 sched:sched_waking:comm=Gecko_IOThread pid=3569 prio=120 target_cpu=003
                                       try_to_wake_up ([kernel.kallsyms])
                                       __libc_write (/usr/lib64/libpthread-2.26.so)
    37.170 IPDL Backgroun/3622 sched:sched_waking:comm=Gecko_IOThread pid=3569 prio=120 target_cpu=003
                                       try_to_wake_up ([kernel.kallsyms])
                                       __libc_write (/usr/lib64/libpthread-2.26.so)
    53.267 IPDL Backgroun/3622 sched:sched_waking:comm=Gecko_IOThread pid=3569 prio=120 target_cpu=003
                                       try_to_wake_up ([kernel.kallsyms])
                                       __libc_write (/usr/lib64/libpthread-2.26.so)
    70.365 IPDL Backgroun/3622 sched:sched_waking:comm=Gecko_IOThread pid=3569 prio=120 target_cpu=003
                                       try_to_wake_up ([kernel.kallsyms])
                                       __libc_write (/usr/lib64/libpthread-2.26.so)
    75.781 Web Content/3649 sched:sched_waking:comm=JS Helper pid=3670 prio=120 target_cpu=000
                                       try_to_wake_up ([kernel.kallsyms])
                                       try_to_wake_up ([kernel.kallsyms])
                                       wake_up_q ([kernel.kallsyms])
                                       futex_wake ([kernel.kallsyms])
                                       do_futex ([kernel.kallsyms])
                                       __x64_sys_futex ([kernel.kallsyms])
                                       do_syscall_64 ([kernel.kallsyms])
                                       entry_SYSCALL_64_after_hwframe ([kernel.kallsyms])
                                       pthread_cond_signal@@GLIBC_2.3.2 (/usr/lib64/libpthread-2.26.so)
  #

  # perf trace -e sched:*switch/nr=2/,block:*_plug/nr=4/,block:*_unplug/nr=1/,net:*dev_queue/nr=3,max-stack=16/
     0.000 :0/0 sched:sched_switch:swapper/0:0 [120] S ==> trace:3367 [120]
     0.046 :0/0 sched:sched_switch:swapper/1:0 [120] S ==> kworker/u16:58:2722 [120]
   570.670 irq/50-iwlwifi/680 net:net_dev_queue:dev=wlp3s0 skbaddr=0xffff93498051ef00 len=66
                                       __dev_queue_xmit ([kernel.kallsyms])
  1106.141 jbd2/dm-0-8/476 block:block_plug:[jbd2/dm-0-8]
  1106.175 jbd2/dm-0-8/476 block:block_unplug:[jbd2/dm-0-8] 1
  1618.088 kworker/u16:30/2694 block:block_plug:[kworker/u16:30]
  1810.000 :0/0 net:net_dev_queue:dev=vnet0 skbaddr=0xffff93498051ef00 len=52
                                       __dev_queue_xmit ([kernel.kallsyms])
  3857.974 :0/0 net:net_dev_queue:dev=vnet0 skbaddr=0xffff93498051f900 len=52
                                       __dev_queue_xmit ([kernel.kallsyms])
  4790.277 jbd2/dm-2-8/748 block:block_plug:[jbd2/dm-2-8]
  4790.448 jbd2/dm-2-8/748 block:block_plug:[jbd2/dm-2-8]
  #

The global --max-events has precendence:

  # trace --max-events 3 -e sched:*switch/nr=2/,block:*_plug/nr=4/,block:*_unplug/nr=1/,net:*dev_queue/nr=3,max-stack=16/
     0.000 :0/0 sched:sched_switch:swapper/0:0 [120] S ==> qemu-system-x86:2252 [120]
     0.029 qemu-system-x8/2252 sched:sched_switch:qemu-system-x86:2252 [120] D ==> swapper/0:0 [120]
    58.047 DNS Res~er #14/31661 net:net_dev_queue:dev=wlp3s0 skbaddr=0xffff9346966af100 len=84
                                       __dev_queue_xmit ([kernel.kallsyms])
                                       __libc_send (/usr/lib64/libpthread-2.26.so)
  #

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: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-s4jswltvh660ughvg9nwngah@git.kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

parent 7ee40678

tools/perf/Documentation/perf-trace.txt

+20 −0

Original line number	Diff line number	Diff line
		@@ -285,6 +285,26 @@ Trace the next min page page fault to take place on the first CPU:
		[0x18b26e6bc2bd] (/tmp/perf-17136.map)
		#

		Trace the next two sched:sched_switch events, four block:*_plug events, the
		next block:_unplug and the next three net:dev_queue events, this last one
		with a backtrace of at most 16 entries, system wide:

		# perf trace -e sched:switch/nr=2/,block:_plug/nr=4/,block:_unplug/nr=1/,net:dev_queue/nr=3,max-stack=16/
		0.000 :0/0 sched:sched_switch:swapper/2:0 [120] S ==> rcu_sched:10 [120]
		0.015 rcu_sched/10 sched:sched_switch:rcu_sched:10 [120] R ==> swapper/2:0 [120]
		254.198 irq/50-iwlwifi/680 net:net_dev_queue:dev=wlp3s0 skbaddr=0xffff93498051f600 len=66
		__dev_queue_xmit ([kernel.kallsyms])
		273.977 :0/0 net:net_dev_queue:dev=wlp3s0 skbaddr=0xffff93498051f600 len=78
		__dev_queue_xmit ([kernel.kallsyms])
		274.007 :0/0 net:net_dev_queue:dev=wlp3s0 skbaddr=0xffff93498051ff00 len=78
		__dev_queue_xmit ([kernel.kallsyms])
		2930.140 kworker/u16:58/2722 block:block_plug:[kworker/u16:58]
		2930.162 kworker/u16:58/2722 block:block_unplug:[kworker/u16:58] 1
		4466.094 jbd2/dm-2-8/748 block:block_plug:[jbd2/dm-2-8]
		8050.123 kworker/u16:30/2694 block:block_plug:[kworker/u16:30]
		8050.271 kworker/u16:30/2694 block:block_plug:[kworker/u16:30]
		#

		SEE ALSO
		--------
		linkperf:perf-record[1], linkperf:perf-script[1]

tools/perf/builtin-trace.c

+17 −2

Original line number	Diff line number	Diff line
		@@ -2092,8 +2092,18 @@ static int trace__event_handler(struct trace trace, struct perf_evsel evsel,
		union perf_event *event __maybe_unused,
		struct perf_sample *sample)
		{
		struct thread *thread = machine__findnew_thread(trace->host, sample->pid, sample->tid);
		struct thread *thread;
		int callchain_ret = 0;
		/*
		* Check if we called perf_evsel__disable(evsel) due to, for instance,
		* this event's max_events having been hit and this is an entry coming
		* from the ring buffer that we should discard, since the max events
		* have already been considered/printed.
		*/
		if (evsel->disabled)
		return 0;

		thread = machine__findnew_thread(trace->host, sample->pid, sample->tid);

		if (sample->callchain) {
		callchain_ret = trace__resolve_callchain(trace, evsel, sample, &callchain_cursor);
		@@ -2142,6 +2152,11 @@ static int trace__event_handler(struct trace trace, struct perf_evsel evsel,
		sample->raw_data, sample->raw_size,
		trace->output);
		++trace->nr_events_printed;

		if (evsel->max_events != ULONG_MAX && ++evsel->nr_events_printed == evsel->max_events) {
		perf_evsel__disable(evsel);
		perf_evsel__close(evsel);
		}
		}
		}

		@@ -2726,7 +2741,7 @@ next_event:
		int timeout = done ? 100 : -1;

		if (!draining && perf_evlist__poll(evlist, timeout) > 0) {
		if (perf_evlist__filter_pollfd(evlist, POLLERR \| POLLHUP) == 0)
		if (perf_evlist__filter_pollfd(evlist, POLLERR \| POLLHUP \| POLLNVAL) == 0)
		draining = true;

		goto again;

tools/perf/util/evsel.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -102,6 +102,7 @@ struct perf_evsel {
		int idx;
		u32 ids;
		unsigned long max_events;
		unsigned long nr_events_printed;
		char *name;
		double scale;
		const char *unit;

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