lkml.org 
[lkml]   [2022]   [Dec]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 1/2][v2] cpuidle-haltpoll: Replace default_idle with arch_cpu_idle
Date
From: Li RongQing <lirongqing@baidu.com>

When KVM guest has MWAIT and mwait_idle is used as default idle function,
but once cpuidle-haltpoll is loaded, default_idle in default_enter_idle is
used, which is using HLT, and cause a performance regression. As the commit
aebef63cf7ff ("x86: Remove vendor checks from prefer_mwait_c1_over_halt")
explains that mwait is preferred

so replace default_idle with arch_cpu_idle which can using MWAIT
optimization.

latency of sockperf ping-pong localhost test is reduced by more 20%
unixbench has 5% performance improvements for single core

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Li RongQing <lirongqing@baidu.com>
---
arch/x86/kernel/process.c | 1 +
drivers/cpuidle/cpuidle-haltpoll.c | 2 +-
2 files changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index c21b734..303afad 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -721,6 +721,7 @@ void arch_cpu_idle(void)
{
x86_idle();
}
+EXPORT_SYMBOL(arch_cpu_idle);

/*
* We use this if we don't have any better idle routine..
diff --git a/drivers/cpuidle/cpuidle-haltpoll.c b/drivers/cpuidle/cpuidle-haltpoll.c
index 3a39a7f..e66df22 100644
--- a/drivers/cpuidle/cpuidle-haltpoll.c
+++ b/drivers/cpuidle/cpuidle-haltpoll.c
@@ -32,7 +32,7 @@ static int default_enter_idle(struct cpuidle_device *dev,
local_irq_enable();
return index;
}
- default_idle();
+ arch_cpu_idle();
return index;
}

--
2.9.4
\
 
 \ /
  Last update: 2022-12-07 13:43    [W:0.176 / U:0.320 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site