perf_counter tools: Small frequency related fixes

Create the counter in a disabled state and only enable it after we
mmap() the buffer, this allows us to see the first few samples (and
observe the frequency ramp).

Furthermore, print the period in the verbose report.

Signed-off-by: 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>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

2 files changed, 7 insertions, 2 deletions

diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index deaee42d5eb0..a5698add2fcb 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -347,6 +347,7 @@ static void create_counter(int counter, int cpu, pid_t pid)
         attr->mmap              = track;
         attr->comm              = track;
         attr->inherit           = (cpu < 0) && inherit;
+        attr->disabled          = 1;
 
         track = 0; /* only the first counter needs these */
 
@@ -402,6 +403,8 @@ try_again:
                 error("failed to mmap with %d (%s)\n", errno, strerror(errno));
                 exit(-1);
         }
+
+        ioctl(fd[nr_cpu][counter], PERF_COUNTER_IOC_ENABLE);
 }
 
 static void open_counters(int cpu, pid_t pid)
diff --git a/tools/perf/builtin-report.c b/tools/perf/builtin-report.c
index 0b18cb99a858..9a0e31e79e9d 100644
--- a/tools/perf/builtin-report.c
+++ b/tools/perf/builtin-report.c
@@ -47,6 +47,7 @@ struct ip_event {
         struct perf_event_header header;
         __u64 ip;
         __u32 pid, tid;
+        __u64 period;
 };
 
 struct mmap_event {
@@ -943,12 +944,13 @@ process_overflow_event(event_t *event, unsigned long offset, unsigned long head)
         uint64_t ip = event->ip.ip;
         struct map *map = NULL;
 
-        dprintf("%p [%p]: PERF_EVENT (IP, %d): %d: %p\n",
+        dprintf("%p [%p]: PERF_EVENT (IP, %d): %d: %p period: %Ld\n",
                 (void *)(offset + head),
                 (void *)(long)(event->header.size),
                 event->header.misc,
                 event->ip.pid,
-                (void *)(long)ip);
+                (void *)(long)ip,
+                (long long)event->ip.period);
 
         dprintf(" ... thread: %s:%d\n", thread->comm, thread->pid);