From 630769e32ba46d9b5cbf2fa107dbbd78479a8af2 Mon Sep 17 00:00:00 2001
From: Yaroslav Furman <yaro330@gmail.com>
Date: Wed, 11 Dec 2019 03:06:26 +0300
Subject: [PATCH] rcu: Fix a performance regression.
Commit "rcu: Create RCU-specific workqueues with rescuers" switched RCU
to using local workqueses and removed power efficiency flag from them.
This caused a performance regression that can be observed in Geekbench 5
after enabling CONFIG_WQ_POWER_EFFICIENT_DEFAULT: score went down from
760/2500 to 620/2300 (single/multi core respectively).
Add WQ_POWER_EFFICIENT flag to avoid this regression.
Change-Id: I2c4f41faa55548f9e81a1c0cbe10703948062d89
---
kernel/rcu/tree.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index ac9094677..a89e4210a 100755
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -4607,10 +4607,10 @@ void __init rcu_init(void)
}
/* Create workqueue for expedited GPs and for Tree SRCU. */
- rcu_gp_wq = alloc_workqueue("rcu_gp", WQ_POWER_EFFICIENT | WQ_MEM_RECLAIM | WQ_UNBOUND, 0);
+ rcu_gp_wq = alloc_workqueue("rcu_gp", WQ_POWER_EFFICIENT | WQ_MEM_RECLAIM, 0);
WARN_ON(!rcu_gp_wq);
- rcu_par_gp_wq = alloc_workqueue("rcu_par_gp", WQ_POWER_EFFICIENT | WQ_MEM_RECLAIM | WQ_UNBOUND, 0);
- WARN_ON(!rcu_par_gp_wq);
+ rcu_par_gp_wq = alloc_workqueue("rcu_par_gp", WQ_POWER_EFFICIENT | WQ_MEM_RECLAIM, 0);
+ WARN_ON(!rcu_par_gp_wq);
srcu_init();
/* Fill in default value for rcutree.qovld boot parameter. */
/* -After- the rcu_node ->lock fields are initialized! */