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Commit f4f0b418 authored by Mike Galbraith's avatar Mike Galbraith Committed by Ingo Molnar
Browse files

perf tools: Remove expensive old debug code from perf top 



Calling gettimeofday() at high frequency is painful for handicapped
boxen. The spot calling gettimeofday() is old unneeded debug code,
so remove it.

Reported-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarMike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1255438640.7173.1.camel@marge.simson.net>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent cfed95a6

tools/perf/builtin-top.c

+1 −14
Original line number Diff line number Diff line
@@ -870,8 +870,6 @@ static unsigned int mmap_read_head(struct mmap_data *md) 
	return head;

}



struct timeval last_read, this_read;



static void mmap_read_counter(struct mmap_data *md)

{

	unsigned int head = mmap_read_head(md);
@@ -879,8 +877,6 @@ static void mmap_read_counter(struct mmap_data *md) 
	unsigned char *data = md->base + page_size;

	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.
@@ -891,14 +887,7 @@ static void mmap_read_counter(struct mmap_data *md) 
	 */

	diff = head - old;

	if (diff > md->mask / 2 || 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.
@@ -906,8 +895,6 @@ static void mmap_read_counter(struct mmap_data *md) 
		old = head;

	}



	last_read = this_read;



	for (; old != head;) {

		event_t *event = (event_t *)&data[old & md->mask];