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>
This commit is contained in:
Peter Zijlstra 2009-06-10 15:03:06 +02:00 committed by Ingo Molnar
parent bd2b5b1284
commit 4502d77c1d
2 changed files with 7 additions and 2 deletions

View file

@ -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)

View file

@ -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);