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From:   Wanpeng Li <kernellwp@gmail.com>
Date:   Wed, 24 Jan 2018 16:07:57 +0800
Message-ID: <CANRm+Cw7tg1=2CFua8-FOuJGPXdkRbgNNBOtGSoz1iJWuxXK2g@mail.gmail.com>
Subject: Re: unixbench context switch perfomance & cpu topology
To:     Mike Galbraith <efault@gmx.de>
Cc:     linux-kernel@vger.kernel.org, kvm <kvm@vger.kernel.org>,
        Paolo Bonzini <pbonzini@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Radim Krcmar <rkrcmar@redhat.com>,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@kernel.org>
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2018-01-23 21:49 GMT+08:00 Mike Galbraith <efault@gmx.de>:
> On Tue, 2018-01-23 at 18:36 +0800, Wanpeng Li wrote:
>>
>> Thanks for having a try, Mike. :) Actually the two context1 tasks
>> don't stack up on one logical cpu at the most of time which is
>> observed by kernelshark. Do you have any idea why there is 4.5 times
>> RESCHED IPIs which is mentioned in another reply for this thread?
>
> See resched_curr().

Yeah, I observe writer/reader pair is running on the same core
sometimes after more digging. Thanks Mike!

Regards,
Wanpeng Li