From: Anton Blanchard <anton@samba.org>
Date: Mon, 3 Apr 2017 21:54:14 +0000 (+1000)
Subject: cpuidle: powernv: Avoid a branch in the core snooze_loop() loop
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=0baa91cb73e296242edad89cfe3f60c59ab8a95a;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git

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 <anton@samba.org>
Reviewed-by: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---

diff --git a/drivers/cpuidle/cpuidle-powernv.c b/drivers/cpuidle/cpuidle-powernv.c
index f8901671fff4..5bb4bb303fba 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;
 	}