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, 13 insertions, 0 deletions

diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index 3056b45b3dd6..09024ec2ab2e 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -13,6 +13,7 @@
 #include "util/util.h"
 #include "util/evlist.h"
 #include "util/evsel.h"
+#include <linux/bitmap.h>
 
 static char const               *script_name;
 static char const               *generate_script_lang;
@@ -21,6 +22,8 @@ static u64			last_timestamp;
 static u64                      nr_unordered;
 extern const struct option      record_options[];
 static bool                     no_callchain;
+static const char               *cpu_list;
+static DECLARE_BITMAP(cpu_bitmap, MAX_NR_CPUS);
 
 enum perf_output_field {
         PERF_OUTPUT_COMM            = 1U << 0,
@@ -453,6 +456,10 @@ static int process_sample_event(union perf_event *event,
                 last_timestamp = sample->time;
                 return 0;
         }
+
+        if (cpu_list && !test_bit(sample->cpu, cpu_bitmap))
+                return 0;
+
         scripting_ops->process_event(event, sample, evsel, session, thread);
 
         session->hists.stats.total_period += sample->period;
@@ -1075,6 +1082,7 @@ static const struct option options[] = {
         OPT_CALLBACK('f', "fields", NULL, "str",
                      "comma separated output fields prepend with 'type:'. Valid types: hw,sw,trace,raw. Fields: comm,tid,pid,time,cpu,event,trace,ip,sym,dso,addr",
                      parse_output_fields),
+        OPT_STRING('c', "cpu", &cpu_list, "cpu", "list of cpus to profile"),
 
         OPT_END()
 };
@@ -1255,6 +1263,11 @@ int cmd_script(int argc, const char **argv, const char *prefix __used)
         if (session == NULL)
                 return -ENOMEM;
 
+        if (cpu_list) {
+                if (perf_session__cpu_bitmap(session, cpu_list, cpu_bitmap))
+                        return -1;
+        }
+
         if (!no_callchain)
                 symbol_conf.use_callchain = true;
         else