From: Peter Zijlstra <peterz@infradead.org>
To: Yang Zhang <yang.zhang.wz@gmail.com>
Cc: linux-kernel@vger.kernel.org, kvm@vger.kernel.org,
wanpeng.li@hotmail.com, mst@redhat.com, pbonzini@redhat.com,
tglx@linutronix.de, rkrcmar@redhat.com, dmatlack@google.com,
agraf@suse.de, linux-doc@vger.kernel.org,
Quan Xu <quan.xu0@gmail.com>, Ingo Molnar <mingo@redhat.com>
Subject: Re: [RFC PATCH v2 7/7] sched/idle: update poll time when wakeup from idle
Date: Tue, 29 Aug 2017 14:46:55 +0200 [thread overview]
Message-ID: <20170829124655.ann5cipoubl5lppn@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <1504007201-12904-8-git-send-email-yang.zhang.wz@gmail.com>
On Tue, Aug 29, 2017 at 11:46:41AM +0000, Yang Zhang wrote:
> In ttwu_do_wakeup, it will update avg_idle when wakeup from idle. Here
> we just reuse this logic to update the poll time. It may be a little
> late to update the poll in ttwu_do_wakeup, but the test result shows no
> obvious performance gap compare with updating poll in irq handler.
>
> one problem is that idle_stamp only used when using CFS scheduler. But
> it is ok since it is the default policy for scheduler and only consider
> it should enough.
>
> Signed-off-by: Yang Zhang <yang.zhang.wz@gmail.com>
> Signed-off-by: Quan Xu <quan.xu0@gmail.com>
Same broken SoB chain, and not a useful word on why you need to adjust
this crap to begin with. What you want that poll duration to be related
to is the cost of a VMEXIT/VMENTER cycle, not however long we happened
to be idle.
So no.
next prev parent reply other threads:[~2017-08-29 12:47 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-29 11:46 [RFC PATCH v2 0/7] x86/idle: add halt poll support Yang Zhang
2017-08-29 11:46 ` [RFC PATCH v2 1/7] x86/paravirt: Add pv_idle_ops to paravirt ops Yang Zhang
2017-08-29 13:55 ` Konrad Rzeszutek Wilk
2017-08-30 7:33 ` Juergen Gross
2017-09-01 6:50 ` Yang Zhang
2017-08-29 11:46 ` [RFC PATCH v2 2/7] KVM guest: register kvm_idle_poll for pv_idle_ops Yang Zhang
2017-08-29 11:46 ` [RFC PATCH v2 3/7] sched/idle: Add poll before enter real idle path Yang Zhang
2017-08-29 12:45 ` Peter Zijlstra
2017-09-01 5:57 ` Quan Xu
2017-09-14 8:41 ` Quan Xu
2017-09-14 9:18 ` Borislav Petkov
2017-08-29 14:39 ` Borislav Petkov
2017-09-01 6:49 ` Quan Xu
2017-09-29 10:39 ` Quan Xu
2017-08-29 11:46 ` [RFC PATCH v2 4/7] x86/paravirt: Add update in x86/paravirt pv_idle_ops Yang Zhang
2017-08-29 11:46 ` [RFC PATCH v2 5/7] Documentation: Add three sysctls for smart idle poll Yang Zhang
2017-08-29 17:20 ` Luis R. Rodriguez
2017-08-29 11:46 ` [RFC PATCH v2 6/7] KVM guest: introduce smart idle poll algorithm Yang Zhang
2017-08-29 11:46 ` [RFC PATCH v2 7/7] sched/idle: update poll time when wakeup from idle Yang Zhang
2017-08-29 12:46 ` Peter Zijlstra [this message]
2017-09-01 7:30 ` Yang Zhang
2017-09-29 10:29 ` Quan Xu
2017-08-29 11:58 ` [RFC PATCH v2 0/7] x86/idle: add halt poll support Alexander Graf
2017-09-01 6:21 ` Yang Zhang
2017-08-29 13:03 ` Andi Kleen
2017-08-29 14:02 ` Wanpeng Li
2017-08-29 14:27 ` Konrad Rzeszutek Wilk
2017-08-29 14:36 ` Michael S. Tsirkin
2017-09-01 6:32 ` Yang Zhang
2017-09-01 6:52 ` Wanpeng Li
2017-09-01 6:44 ` Yang Zhang
2017-09-01 6:58 ` Wanpeng Li
2017-09-01 7:53 ` Yang Zhang
2017-08-29 14:56 ` Michael S. Tsirkin
2017-09-13 11:56 ` Yang Zhang
2017-09-14 8:36 ` Quan Xu
2017-09-14 9:19 ` Wanpeng Li
2017-09-14 9:40 ` Quan Xu
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