linux-kernel - [PATCH RFC V2 09/10] perf top: add option to set the number of thread for event synthesize

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Date:   Sun, 10 Sep 2017 19:23:22 -0700
From:   kan.liang@...el.com
To:     acme@...nel.org, peterz@...radead.org, mingo@...hat.com,
        linux-kernel@...r.kernel.org
Cc:     jolsa@...nel.org, namhyung@...nel.org, adrian.hunter@...el.com,
        lukasz.odzioba@...el.com, ak@...ux.intel.com,
        Kan Liang <kan.liang@...el.com>
Subject: [PATCH RFC V2 09/10] perf top: add option to set the number of thread for event synthesize

From: Kan Liang <kan.liang@...el.com>

Using UINT_MAX to indicate the default thread#, which is the max number
of online CPU.

Signed-off-by: Kan Liang <kan.liang@...el.com>
---
 tools/perf/builtin-top.c | 5 ++++-
 tools/perf/util/event.c  | 5 ++++-
 tools/perf/util/top.h    | 1 +
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 4b8fdc1..5f59aa7 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -961,7 +961,7 @@ static int __cmd_top(struct perf_top *top)
 	machine__synthesize_threads(&top->session->machines.host, &opts->target,
 				    top->evlist->threads, false,
 				    opts->proc_map_timeout,
-				    (unsigned int)sysconf(_SC_NPROCESSORS_ONLN));
+				    top->nr_threads_synthesize);
 
 	if (perf_hpp_list.socket) {
 		ret = perf_env__read_cpu_topology_map(&perf_env);
@@ -1114,6 +1114,7 @@ int cmd_top(int argc, const char **argv)
 		},
 		.max_stack	     = sysctl_perf_event_max_stack,
 		.sym_pcnt_filter     = 5,
+		.nr_threads_synthesize = UINT_MAX,
 	};
 	struct record_opts *opts = &top.record_opts;
 	struct target *target = &opts->target;
@@ -1223,6 +1224,8 @@ int cmd_top(int argc, const char **argv)
 	OPT_BOOLEAN(0, "hierarchy", &symbol_conf.report_hierarchy,
 		    "Show entries in a hierarchy"),
 	OPT_BOOLEAN(0, "force", &symbol_conf.force, "don't complain, do it"),
+	OPT_UINTEGER(0, "num-thread-synthesize", &top.nr_threads_synthesize,
+			"number of thread to run event synthesize"),
 	OPT_END()
 	};
 	const char * const top_usage[] = {
diff --git a/tools/perf/util/event.c b/tools/perf/util/event.c
index 8c4e072..ecef279 100644
--- a/tools/perf/util/event.c
+++ b/tools/perf/util/event.c
@@ -778,7 +778,10 @@ int perf_event__synthesize_threads(struct perf_tool *tool,
 	if (n < 0)
 		return err;
 
-	thread_nr = nr_threads_synthesize;
+	if (nr_threads_synthesize == UINT_MAX)
+		thread_nr = sysconf(_SC_NPROCESSORS_ONLN);
+	else
+		thread_nr = nr_threads_synthesize;
 	if (thread_nr <= 0)
 		thread_nr = 1;
 	if (thread_nr > n)
diff --git a/tools/perf/util/top.h b/tools/perf/util/top.h
index 9bdfb78..f4296e1 100644
--- a/tools/perf/util/top.h
+++ b/tools/perf/util/top.h
@@ -37,6 +37,7 @@ struct perf_top {
 	int		   sym_pcnt_filter;
 	const char	   *sym_filter;
 	float		   min_percent;
+	unsigned int	   nr_threads_synthesize;
 };
 
 #define CONSOLE_CLEAR ".[H.[2J"
-- 
2.5.5