blktrace: use cpu_clock() instead of sched_clock()
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>
diff --git a/block/blktrace.c b/block/blktrace.c
index 20c3e22..20fa034 100644
--- a/block/blktrace.c
+++ b/block/blktrace.c
@@ -41,7 +41,7 @@
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 @@
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 @@
}
/*
- * 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_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();
}