From 0baa91cb73e296242edad89cfe3f60c59ab8a95a Mon Sep 17 00:00:00 2001 From: Anton Blanchard Date: Tue, 4 Apr 2017 07:54:14 +1000 Subject: [PATCH] cpuidle: powernv: Avoid a branch in the core snooze_loop() loop When in the snooze_loop() we want to take up the least amount of resources. On my version of gcc (6.3), we end up with an extra branch because it predicts snooze_timeout_en to be false, whereas it is almost always true. Use likely() to avoid the branch and be a little nicer to the other non idle threads on the core. Signed-off-by: Anton Blanchard Reviewed-by: Vaidyanathan Srinivasan Signed-off-by: Rafael J. Wysocki --- drivers/cpuidle/cpuidle-powernv.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c index f890167..5bb4bb3 100644 --- a/drivers/cpuidle/cpuidle-powernv.c +++ b/drivers/cpuidle/cpuidle-powernv.c @@ -58,7 +58,7 @@ static int snooze_loop(struct cpuidle_device *dev, ppc64_runlatch_off(); HMT_very_low(); while (!need_resched()) { - if (snooze_timeout_en && get_tb() > snooze_exit_time) + if (likely(snooze_timeout_en) && get_tb() > snooze_exit_time) break; } -- 2.7.4