perf record: remove unneeded gettimeofday() call
Perf record repeatedly calls gettimeofday() which adds noise to the performance
measurements. Since gettimeofday() is only used for the error printf, delete
it.
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
LKML-Reference: <20100518225240.GC25589@sgi.com>
Signed-off-by: Russ Anderson <rja@sgi.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
index 66b8ecd..e672269 100644
--- a/tools/perf/builtin-record.c
+++ b/tools/perf/builtin-record.c
@@ -65,9 +65,6 @@
static int multiplex_fd = -1;
static long samples = 0;
-static struct timeval last_read;
-static struct timeval this_read;
-
static u64 bytes_written = 0;
static struct pollfd *event_array;
@@ -147,8 +144,6 @@
void *buf;
int diff;
- gettimeofday(&this_read, NULL);
-
/*
* If we're further behind than half the buffer, there's a chance
* the writer will bite our tail and mess up the samples under us.
@@ -159,23 +154,13 @@
*/
diff = head - old;
if (diff < 0) {
- struct timeval iv;
- unsigned long msecs;
-
- timersub(&this_read, &last_read, &iv);
- msecs = iv.tv_sec*1000 + iv.tv_usec/1000;
-
- fprintf(stderr, "WARNING: failed to keep up with mmap data."
- " Last read %lu msecs ago.\n", msecs);
-
+ fprintf(stderr, "WARNING: failed to keep up with mmap data\n");
/*
* head points to a known good entry, start there.
*/
old = head;
}
- last_read = this_read;
-
if (old != head)
samples++;