Messages in this thread Patch in this message | | | From | lirongqing@baidu ... | Subject | [PATCH 1/2][v2] cpuidle-haltpoll: Replace default_idle with arch_cpu_idle | Date | Wed, 7 Dec 2022 20:41:34 +0800 |
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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
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