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>

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 30b83de..de76008 100644 (file)
--- 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,