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perf tools: Remove expensive old debug code from perf top

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

Reported-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Mike 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: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Mike Galbraith 2009-10-13 14:57:20 +02:00 committed by Ingo Molnar
parent cfed95a693
commit f4f0b41818
1 changed files with 1 additions and 14 deletions
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15
tools/perf/builtin-top.c
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@ -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];