From: Ingo Molnar use cpu_clock() instead of sched_clock(). (the latter is not a proper clock-source) Signed-off-by: Ingo Molnar Cc: Jens Axboe Signed-off-by: Andrew Morton --- block/blktrace.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff -puN block/blktrace.c~blktrace-use-cpu_clock-instead-of-sched_clock block/blktrace.c --- a/block/blktrace.c~blktrace-use-cpu_clock-instead-of-sched_clock +++ a/block/blktrace.c @@ -41,7 +41,7 @@ static void trace_note(struct blk_trace 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 *b 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_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 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(); } _