perf record: Add missing -C option support for specifying profile cpu

perf top supports a -C for setting the profile CPU, but perf
record does not. This adds the same option for perf record,
allowing the user to specify a specific target profile CPU.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20090812091801.GC12579@kernel.dk>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 14 insertions, 3 deletions

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 30b83def03d4..de76008fbaa2 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -35,6 +35,7 @@ static const char		*output_name			= "perf.data";
 static int                      group                           = 0;
 static unsigned int             realtime_prio                   = 0;
 static int                      system_wide                     = 0;
+static int                      profile_cpu                     = -1;
 static pid_t                    target_pid                      = -1;
 static int                      inherit                         = 1;
 static int                      force                           = 0;
@@ -431,6 +432,8 @@ try_again:
 
                 if (err == EPERM)
                         die("Permission error - are you root?\n");
+                else if (err ==  ENODEV && profile_cpu != -1)
+                        die("No such device - did you specify an out-of-range profile CPU?\n");
 
                 /*
                  * If it's cycles then fall back to hrtimer
@@ -564,9 +567,15 @@ static int __cmd_record(int argc, const char **argv)
                 if (pid == -1)
                         pid = getpid();
 
-                open_counters(-1, pid);
-        } else for (i = 0; i < nr_cpus; i++)
-                open_counters(i, target_pid);
+                open_counters(profile_cpu, pid);
+        } else {
+                if (profile_cpu != -1) {
+                        open_counters(profile_cpu, target_pid);
+                } else {
+                        for (i = 0; i < nr_cpus; i++)
+                                open_counters(i, target_pid);
+                }
+        }
 
         if (file_new)
                 perf_header__write(header, output);
@@ -645,6 +654,8 @@ static const struct option options[] = {
                             "system-wide collection from all CPUs"),
         OPT_BOOLEAN('A', "append", &append_file,
                             "append to the output file to do incremental profiling"),
+        OPT_INTEGER('C', "profile_cpu", &profile_cpu,
+                            "CPU to profile on"),
         OPT_BOOLEAN('f', "force", &force,
                         "overwrite existing data file"),
         OPT_LONG('c', "count", &default_interval,