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From: Wanpeng Li <kernellwp@gmail.com>
Date: Mon, 10 Jul 2017 17:29:00 +0800
Message-ID: <CANRm+Cwtg8=KQW3AAgyDi=8U30F0+TD2EDXU_dEMdB5uHF4MBg@mail.gmail.com>
Subject: Re: [RFC PATCH v1 00/11] Create fast idle path for short idle periods
To: Peter Zijlstra <peterz@infradead.org>
Cc: Aubrey Li <aubrey.li@intel.com>, Thomas Gleixner <tglx@linutronix.de>,
        Len Brown <len.brown@intel.com>,
        "Rafael J. Wysocki" <rjw@rjwysocki.net>, ak@linux.intel.com,
        Tim Chen <tim.c.chen@linux.intel.com>, arjan@linux.intel.com,
        "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
        Yang Zhang <yang.zhang.wz@gmail.com>,
        "the arch/x86 maintainers" <x86@kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Aubrey Li <aubrey.li@linux.intel.com>
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2017-07-10 16:46 GMT+08:00 Peter Zijlstra <peterz@infradead.org>:
> On Mon, Jul 10, 2017 at 09:38:30AM +0800, Aubrey Li wrote:
>> We measured 3%~5% improvemnt in disk IO workload, and 8%~20% improvement in
>> network workload.
>
> Argh, what a mess :/

Agreed, this patchset is a variant of
https://lkml.org/lkml/2017/6/22/296 As I mentioned before, we should
not churn the core path.

Regards,
Wanpeng Li

>
> So how much of the gain is simply due to skipping NOHZ? Mike used to
> carry a patch that would throttle NOHZ. And that is a _far_ smaller and
> simpler patch to do.