Commit 340b47f5 authored Sep 29, 2017 by Kan Liang Committed by Arnaldo Carvalho de Melo Oct 03, 2017

perf top: Implement multithreading for perf_event__synthesize_threads



The proc files which is sorted with alphabetical order are evenly
assigned to several synthesize threads to be processed in parallel.

For 'perf top', the threads number hard code to online CPU number. The
following patch will introduce an option to set it.

For other perf tools, the thread number is 1. Because the process
function is not ready for multithreading, e.g.
process_synthesized_event.

This patch series only support event synthesize multithreading for 'perf
top'. For other tools, it can be done separately later.

With multithread applied, the total processing time can get up to 1.56x
speedup on Knights Mill for 'perf top'.

For specific single event processing, the processing time could increase
because of the lock contention. So proc_map_timeout may need to be
increased. Otherwise some proc maps will be truncated.

Based on my test, increasing the proc_map_timeout has small impact
on the total processing time. The total processing time still get 1.49x
speedup on Knights Mill after increasing the proc_map_timeout.
The patch itself doesn't increase the proc_map_timeout.

Doesn't need to implement multithreading for per task monitoring,
perf_event__synthesize_thread_map. It doesn't have performance issue.

Committer testing:

  # getconf _NPROCESSORS_ONLN
  4
  # perf trace --no-inherit -e clone -o /tmp/output perf top
  # tail -4 /tmp/bla
     0.124 ( 0.041 ms): clone(flags: VM|FS|FILES|SIGHAND|THREAD|SYSVSEM|SETTLS|PARENT_SETTID|CHILD_CLEARTID, child_stack: 0x7fc3eb3a8f30, parent_tidptr: 0x7fc3eb3a99d0, child_tidptr: 0x7fc3eb3a99d0, tls: 0x7fc3eb3a9700) = 9548 (perf)
     0.246 ( 0.023 ms): clone(flags: VM|FS|FILES|SIGHAND|THREAD|SYSVSEM|SETTLS|PARENT_SETTID|CHILD_CLEARTID, child_stack: 0x7fc3eaba7f30, parent_tidptr: 0x7fc3eaba89d0, child_tidptr: 0x7fc3eaba89d0, tls: 0x7fc3eaba8700) = 9549 (perf)
     0.286 ( 0.019 ms): clone(flags: VM|FS|FILES|SIGHAND|THREAD|SYSVSEM|SETTLS|PARENT_SETTID|CHILD_CLEARTID, child_stack: 0x7fc3ea3a6f30, parent_tidptr: 0x7fc3ea3a79d0, child_tidptr: 0x7fc3ea3a79d0, tls: 0x7fc3ea3a7700) = 9550 (perf)
   246.540 ( 0.047 ms): clone(flags: VM|FS|FILES|SIGHAND|THREAD|SYSVSEM|SETTLS|PARENT_SETTID|CHILD_CLEARTID, child_stack: 0x7fc3ea3a6f30, parent_tidptr: 0x7fc3ea3a79d0, child_tidptr: 0x7fc3ea3a79d0, tls: 0x7fc3ea3a7700) = 9551 (perf)
  #

Signed-off-by: Kan Liang <kan.liang@intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: He Kuang <hekuang@huawei.com>
Cc: Lukasz Odzioba <lukasz.odzioba@intel.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1506696477-146932-4-git-send-email-kan.liang@intel.com


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

parent f988e71b

tools/perf/builtin-kvm.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -1441,7 +1441,8 @@ static int kvm_events_live(struct perf_kvm_stat *kvm,
		perf_session__set_id_hdr_size(kvm->session);
		ordered_events__set_copy_on_queue(&kvm->session->ordered_events, true);
		machine__synthesize_threads(&kvm->session->machines.host, &kvm->opts.target,
		kvm->evlist->threads, false, kvm->opts.proc_map_timeout);
		kvm->evlist->threads, false,
		kvm->opts.proc_map_timeout, 1);
		err = kvm_live_open_events(kvm);
		if (err)
		goto out;

tools/perf/builtin-record.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -863,7 +863,7 @@ static int record__synthesize(struct record *rec, bool tail)

		err = __machine__synthesize_threads(machine, tool, &opts->target, rec->evlist->threads,
		process_synthesized_event, opts->sample_address,
		opts->proc_map_timeout);
		opts->proc_map_timeout, 1);
		out:
		return err;
		}

tools/perf/builtin-top.c

+7 −1

Original line number	Diff line number	Diff line
		@@ -958,8 +958,14 @@ static int __cmd_top(struct perf_top *top)
		if (perf_session__register_idle_thread(top->session) < 0)
		goto out_delete;

		perf_set_multithreaded();

		machine__synthesize_threads(&top->session->machines.host, &opts->target,
		top->evlist->threads, false, opts->proc_map_timeout);
		top->evlist->threads, false,
		opts->proc_map_timeout,
		(unsigned int)sysconf(_SC_NPROCESSORS_ONLN));

		perf_set_singlethreaded();

		if (perf_hpp_list.socket) {
		ret = perf_env__read_cpu_topology_map(&perf_env);

tools/perf/builtin-trace.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1131,7 +1131,7 @@ static int trace__symbols_init(struct trace trace, struct perf_evlist evlist)

		err = __machine__synthesize_threads(trace->host, &trace->tool, &trace->opts.target,
		evlist->threads, trace__tool_process, false,
		trace->opts.proc_map_timeout);
		trace->opts.proc_map_timeout, 1);
		if (err)
		symbol__exit();

tools/perf/tests/mmap-thread-lookup.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -131,7 +131,7 @@ static int synth_all(struct machine *machine)
		{
		return perf_event__synthesize_threads(NULL,
		perf_event__process,
		machine, 0, 500);
		machine, 0, 500, 1);
		}

		static int synth_process(struct machine *machine)

Admin message