perf report/annotate/script: Add option to specify a CPU range

Add an option to perf report/annotate/script to specify which
CPUs to operate on. This enables us to take a single system wide
profile and analyse each CPU (or group of CPUs) in isolation.

This was useful when profiling a multiprocess workload where the
bottleneck was on one CPU but this was hidden in the overall
profile. Per process and per thread breakdowns didn't help
because multiple processes were running on each CPU and no
single process consumed an entire CPU.

The patch converts the list of CPUs returned by cpu_map__new
into a bitmap for fast lookup. I wanted to use -C to be
consistent with perf top/record/stat, but unfortunately perf
report already uses -C <comms>.

 v2: Incorporate suggestions from David Ahern:
	- Added -c to perf script
	- Check that SAMPLE_CPU is set when -c is used
	- Update documentation

 v3: Create perf_session__cpu_bitmap()

Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: David Ahern <dsahern@gmail.com>
Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
Link: http://lkml.kernel.org/r/20110704215750.11647eb9@kryten
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 15 insertions, 0 deletions

diff --git a/tools/perf/builtin-annotate.c b/tools/perf/builtin-annotate.c
index 7b139e1e7e8..555aefd7fe0 100644
--- a/tools/perf/builtin-annotate.c
+++ b/tools/perf/builtin-annotate.c
@@ -28,6 +28,8 @@
 #include "util/hist.h"
 #include "util/session.h"
 
+#include <linux/bitmap.h>
+
 static char		const *input_name = "perf.data";
 
 static bool		force, use_tui, use_stdio;
@@ -38,6 +40,9 @@ static bool		print_line;
 
 static const char *sym_hist_filter;
 
+static const char	*cpu_list;
+static DECLARE_BITMAP(cpu_bitmap, MAX_NR_CPUS);
+
 static int perf_evlist__add_sample(struct perf_evlist *evlist,
 				   struct perf_sample *sample,
 				   struct perf_evsel *evsel,
@@ -90,6 +95,9 @@ static int process_sample_event(union perf_event *event,
 		return -1;
 	}
 
+	if (cpu_list && !test_bit(sample->cpu, cpu_bitmap))
+		return 0;
+
 	if (!al.filtered &&
 	    perf_evlist__add_sample(session->evlist, sample, evsel, &al)) {
 		pr_warning("problem incrementing symbol count, "
@@ -177,6 +185,12 @@ static int __cmd_annotate(void)
 	if (session == NULL)
 		return -ENOMEM;
 
+	if (cpu_list) {
+		ret = perf_session__cpu_bitmap(session, cpu_list, cpu_bitmap);
+		if (ret)
+			goto out_delete;
+	}
+
 	ret = perf_session__process_events(session, &event_ops);
 	if (ret)
 		goto out_delete;
@@ -252,6 +266,7 @@ static const struct option options[] = {
 		    "print matching source lines (may be slow)"),
 	OPT_BOOLEAN('P', "full-paths", &full_paths,
 		    "Don't shorten the displayed pathnames"),
+	OPT_STRING('c', "cpu", &cpu_list, "cpu", "list of cpus to profile"),
 	OPT_END()
 };