From: Daniel Bristot de Oliveira <bristot@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Avi Kivity <avi@scylladb.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
linux-api <linux-api@vger.kernel.org>,
"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
Boqun Feng <boqun.feng@gmail.com>, Andrew Hunter <ahh@google.com>,
maged michael <maged.michael@gmail.com>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Paul Mackerras <paulus@samba.org>,
Michael Ellerman <mpe@ellerman.id.au>,
Dave Watson <davejwatson@fb.com>, Ingo Molnar <mingo@redhat.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Andrea Parri <parri.andrea@gmail.com>,
"Russell King, ARM Linux" <linux@armlinux.org.uk>,
Greg Hackmann <ghackmann@google.com>,
Will Deacon <will.deacon@arm.com>, David Sehr <sehr@google.com>,
x86 <x86@kernel.org>
Subject: Re: [RFC PATCH 0/2] x86: Fix missing core serialization on migration
Date: Tue, 14 Nov 2017 19:24:22 +0100 [thread overview]
Message-ID: <95f902ea-3e97-0280-2d52-28cadef7806d@redhat.com> (raw)
In-Reply-To: <20171114181732.bwahj6woik27trou@hirez.programming.kicks-ass.net>
On 11/14/2017 07:17 PM, Peter Zijlstra wrote:
> On Tue, Nov 14, 2017 at 07:01:55PM +0100, Daniel Bristot de Oliveira wrote:
>> On 11/14/2017 06:40 PM, Peter Zijlstra wrote:
>>> On Tue, Nov 14, 2017 at 06:17:13PM +0100, Daniel Bristot de Oliveira wrote:
>>>
>>>> IIRC, if the dest cpu is idle and the system is with idle=poll, no IPI
>>>> is fired as well, but that is not a very common case.
>>>
>>> You're thinking about wake from idle? That is almost always without IPI,
>>> even without idle=poll.
>>>
>>
>> I meant the resched_curr(rq) of an rq on another CPU. If the dest is
>> idle && idle=poll, the IPI will not be send.
>
> I'm saying the IPI will not be send even without idle=poll. MWAIT based
> idle will also have TIF_POLLING_NRFLAG set.
>
Yeah! you are right! I missed that point... sorry :-)
-- Daniel
WARNING: multiple messages have this Message-ID (diff)
From: Daniel Bristot de Oliveira <bristot-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
To: Peter Zijlstra <peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
Cc: Andy Lutomirski <luto-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>,
Mathieu Desnoyers
<mathieu.desnoyers-vg+e7yoeK/dWk0Htik3J/w@public.gmane.org>,
Avi Kivity <avi-VrcmuVmyx1hWk0Htik3J/w@public.gmane.org>,
Linus Torvalds
<torvalds-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>,
linux-kernel
<linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
linux-api <linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
"Paul E. McKenney"
<paulmck-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>,
Boqun Feng <boqun.feng-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Andrew Hunter <ahh-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>,
maged michael
<maged.michael-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
Benjamin Herrenschmidt
<benh-XVmvHMARGAS8U2dJNN8I7kB+6BGkLq7r@public.gmane.org>,
Paul Mackerras <paulus-eUNUBHrolfbYtjvyW6yDsg@public.gmane.org>,
Michael Ellerman <mpe-Gsx/Oe8HsFggBc27wqDAHg@public.gmane.org>,
Dave Watson <davejwatson-b10kYP2dOMg@public.gmane.org>,
Ingo Molnar <mingo-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>,
"H. Peter Anvin" <hpa-YMNOUZJC4hwAvxtiuMwx3w@public.gmane.org>,
Andrea Parri
<parri.andrea-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>,
"Russell King, ARM Linux" <linux@armlinux.o>
Subject: Re: [RFC PATCH 0/2] x86: Fix missing core serialization on migration
Date: Tue, 14 Nov 2017 19:24:22 +0100 [thread overview]
Message-ID: <95f902ea-3e97-0280-2d52-28cadef7806d@redhat.com> (raw)
In-Reply-To: <20171114181732.bwahj6woik27trou-Nxj+rRp3nVydTX5a5knrm8zTDFooKrT+cvkQGrU6aU0@public.gmane.org>
On 11/14/2017 07:17 PM, Peter Zijlstra wrote:
> On Tue, Nov 14, 2017 at 07:01:55PM +0100, Daniel Bristot de Oliveira wrote:
>> On 11/14/2017 06:40 PM, Peter Zijlstra wrote:
>>> On Tue, Nov 14, 2017 at 06:17:13PM +0100, Daniel Bristot de Oliveira wrote:
>>>
>>>> IIRC, if the dest cpu is idle and the system is with idle=poll, no IPI
>>>> is fired as well, but that is not a very common case.
>>>
>>> You're thinking about wake from idle? That is almost always without IPI,
>>> even without idle=poll.
>>>
>>
>> I meant the resched_curr(rq) of an rq on another CPU. If the dest is
>> idle && idle=poll, the IPI will not be send.
>
> I'm saying the IPI will not be send even without idle=poll. MWAIT based
> idle will also have TIF_POLLING_NRFLAG set.
>
Yeah! you are right! I missed that point... sorry :-)
-- Daniel
next prev parent reply other threads:[~2017-11-14 18:24 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-10 21:12 [RFC PATCH 0/2] x86: Fix missing core serialization on migration Mathieu Desnoyers
2017-11-10 21:12 ` Mathieu Desnoyers
2017-11-10 21:12 ` [RFC PATCH 1/2] x86: Introduce sync_core_before_usermode Mathieu Desnoyers
2017-11-10 21:12 ` Mathieu Desnoyers
2017-11-10 21:12 ` [RFC PATCH 2/2] Fix: x86: Add missing core serializing instruction on migration Mathieu Desnoyers
2017-11-10 21:12 ` Mathieu Desnoyers
2017-11-10 21:36 ` [RFC PATCH 0/2] x86: Fix missing core serialization " Linus Torvalds
2017-11-10 21:36 ` Linus Torvalds
2017-11-10 21:57 ` Mathieu Desnoyers
2017-11-10 21:57 ` Mathieu Desnoyers
2017-11-10 22:12 ` Linus Torvalds
2017-11-10 22:12 ` Linus Torvalds
2017-11-13 16:56 ` Mathieu Desnoyers
2017-11-13 16:56 ` Mathieu Desnoyers
2017-11-13 17:14 ` Linus Torvalds
2017-11-13 17:14 ` Linus Torvalds
2017-11-14 14:53 ` Avi Kivity
2017-11-14 14:53 ` Avi Kivity
2017-11-14 15:17 ` Mathieu Desnoyers
2017-11-14 15:17 ` Mathieu Desnoyers
2017-11-14 15:42 ` Avi Kivity
2017-11-14 15:42 ` Avi Kivity
2017-11-14 16:05 ` Peter Zijlstra
2017-11-14 16:05 ` Peter Zijlstra
2017-11-14 16:08 ` Peter Zijlstra
2017-11-14 16:08 ` Peter Zijlstra
2017-11-14 16:49 ` Mathieu Desnoyers
2017-11-14 16:49 ` Mathieu Desnoyers
2017-11-14 17:03 ` Avi Kivity
2017-11-14 17:03 ` Avi Kivity
2017-11-14 17:10 ` Mathieu Desnoyers
2017-11-14 17:10 ` Mathieu Desnoyers
2017-11-14 17:31 ` Linus Torvalds
2017-11-14 17:31 ` Linus Torvalds
2017-11-14 16:10 ` Andy Lutomirski
2017-11-14 16:10 ` Andy Lutomirski
2017-11-14 16:13 ` Thomas Gleixner
2017-11-14 16:13 ` Thomas Gleixner
2017-11-14 16:16 ` Andy Lutomirski
2017-11-14 16:16 ` Andy Lutomirski
2017-11-14 16:31 ` Peter Zijlstra
2017-11-14 16:31 ` Peter Zijlstra
2017-11-14 17:17 ` Daniel Bristot de Oliveira
2017-11-14 17:17 ` Daniel Bristot de Oliveira
2017-11-14 17:40 ` Peter Zijlstra
2017-11-14 17:40 ` Peter Zijlstra
2017-11-14 18:01 ` Daniel Bristot de Oliveira
2017-11-14 18:01 ` Daniel Bristot de Oliveira
2017-11-14 18:17 ` Peter Zijlstra
2017-11-14 18:17 ` Peter Zijlstra
2017-11-14 18:24 ` Daniel Bristot de Oliveira [this message]
2017-11-14 18:24 ` Daniel Bristot de Oliveira
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