Commit a83bc47c authored by Steven Rostedt's avatar Steven Rostedt Committed by Ingo Molnar

sched_clock: record TSC after gtod

To read the gtod we need to grab the xtime lock for read. Reading the gtod
before the TSC can cause a bigger gab if the xtime lock is contended.

This patch simply reverses the order to read the TSC after the gtod.
The locking in the reading of the gtod handles any barriers one might
think is needed.
Signed-off-by: default avatarSteven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: john stultz <johnstul@us.ibm.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent c0c87734
...@@ -237,8 +237,8 @@ void sched_clock_tick(void) ...@@ -237,8 +237,8 @@ void sched_clock_tick(void)
WARN_ON_ONCE(!irqs_disabled()); WARN_ON_ONCE(!irqs_disabled());
now = sched_clock();
now_gtod = ktime_to_ns(ktime_get()); now_gtod = ktime_to_ns(ktime_get());
now = sched_clock();
__raw_spin_lock(&scd->lock); __raw_spin_lock(&scd->lock);
__update_sched_clock(scd, now, NULL); __update_sched_clock(scd, now, NULL);
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment