[PATCH] sched/idle: Stop the tick when no cpuidle driver is available
Christian Loehle <[email protected]>
| Newsgroups | org.kernel.vger.linux-pm,dev.linux.lists.regressions,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
Commit f4c31b07b136 ("sched: idle: Consolidate the handling of two
special cases") changed the no-cpuidle-driver path to use the previous
tick wakeup heuristic.
Oracle reported a substantial sysbench regression on small OCI VM shapes
with no cpuidle driver available. Reverting the commit recovered the lost
performance.
Restore the previous tick handling for the no-driver case while retaining
the heuristic for the single-state cpuidle case.
Fixes: f4c31b07b136 ("sched: idle: Consolidate the handling of two special cases")
Reported-by: Joseph Salisbury <[email protected]>
Closes: https://lore.kernel.org/all/[email protected]/
Signed-off-by: Christian Loehle <[email protected]>
---
Here's the actual patch, I'd still be curious about why this happens here...
kernel/sched/idle.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c
index 052435f4d3e3..a814f9d5759f 100644
--- a/kernel/sched/idle.c
+++ b/kernel/sched/idle.c
@@ -194,7 +194,7 @@ static void cpuidle_idle_call(bool stop_tick)
}
if (cpuidle_not_available(drv, dev)) {
- idle_call_stop_or_retain_tick(stop_tick);
+ tick_nohz_idle_stop_tick();
default_idle_call();
goto exit_idle;
--
2.34.1