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blktrace: use cpu_clock() instead of sched_clock()

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use cpu_clock() instead of sched_clock(). (the latter is not a proper
clock-source)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
This commit is contained in:
Ingo Molnar 2007-07-25 13:07:10 +02:00 committed by Jens Axboe
parent 4d5d8e9d3e
commit 7c2ff389bb
1 changed files with 10 additions and 10 deletions
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20
block/blktrace.c
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@ -41,7 +41,7 @@ static void trace_note(struct blk_trace *bt, pid_t pid, int action,
const int cpu = smp_processor_id();
t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
t->time = sched_clock() - per_cpu(blk_trace_cpu_offset, cpu);
t->time = cpu_clock(cpu) - per_cpu(blk_trace_cpu_offset, cpu);
t->device = bt->dev;
t->action = action;
t->pid = pid;
@ -159,7 +159,7 @@ void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
t->sequence = ++(*sequence);
t->time = sched_clock() - per_cpu(blk_trace_cpu_offset, cpu);
t->time = cpu_clock(cpu) - per_cpu(blk_trace_cpu_offset, cpu);
t->sector = sector;
t->bytes = bytes;
t->action = what;
@ -488,17 +488,17 @@ void blk_trace_shutdown(struct request_queue *q)
}
/*
* Average offset over two calls to sched_clock() with a gettimeofday()
* Average offset over two calls to cpu_clock() with a gettimeofday()
* in the middle
*/
static void blk_check_time(unsigned long long *t)
static void blk_check_time(unsigned long long *t, int this_cpu)
{
unsigned long long a, b;
struct timeval tv;
a = sched_clock();
a = cpu_clock(this_cpu);
do_gettimeofday(&tv);
b = sched_clock();
b = cpu_clock(this_cpu);
*t = tv.tv_sec * 1000000000 + tv.tv_usec * 1000;
*t -= (a + b) / 2;
@ -510,16 +510,16 @@ static void blk_check_time(unsigned long long *t)
static void blk_trace_check_cpu_time(void *data)
{
unsigned long long *t;
int cpu = get_cpu();
int this_cpu = get_cpu();
t = &per_cpu(blk_trace_cpu_offset, cpu);
t = &per_cpu(blk_trace_cpu_offset, this_cpu);
/*
* Just call it twice, hopefully the second call will be cache hot
* and a little more precise
*/
blk_check_time(t);
blk_check_time(t);
blk_check_time(t, this_cpu);
blk_check_time(t, this_cpu);
put_cpu();
}