linux-kernel - RE: [PATCH 1/2][v2] cpuidle-haltpoll: Replace default_idle with arch_cpu

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Date:   Fri, 9 Dec 2022 13:44:39 +0000
From:   "Li,Rongqing" <lirongqing@...du.com>
To:     "Rafael J. Wysocki" <rafael@...nel.org>
CC:     "tglx@...utronix.de" <tglx@...utronix.de>,
        "mingo@...hat.com" <mingo@...hat.com>,
        "bp@...en8.de" <bp@...en8.de>,
        "dave.hansen@...ux.intel.com" <dave.hansen@...ux.intel.com>,
        "x86@...nel.org" <x86@...nel.org>,
        "daniel.lezcano@...aro.org" <daniel.lezcano@...aro.org>,
        "peterz@...radead.org" <peterz@...radead.org>,
        "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>,
        "tony.luck@...el.com" <tony.luck@...el.com>,
        "jpoimboe@...nel.org" <jpoimboe@...nel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-pm@...r.kernel.org" <linux-pm@...r.kernel.org>
Subject: RE: [PATCH 1/2][v2] cpuidle-haltpoll: Replace default_idle with
 arch_cpu_idle

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

Sorry, The upper data are wrong since wrong governor is used

when guest has mwait, and haltpoll driver is loaded and haltpoll governor is used.

on Intel cpu, unixbench score are nearly same, but sockperf has 20% low latency 
on AMD milan cpu, the sockperf latency are similar , but unixbench single core score has 10% loss, because AMD cpu maybe has weak smt capability 

Replace default idle with arch cpu idle has little effect


Thanks

-Li


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