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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: 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];