From: Peter Zijlstra <peterz@infradead.org>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Wanpeng Li <kernellwp@gmail.com>, Mike Galbraith <efault@gmx.de>,
LKML <linux-kernel@vger.kernel.org>, Ingo Molnar <mingo@elte.hu>,
Borislav Petkov <bp@alien8.de>
Subject: Re: tip.today - scheduler bam boom crash (cpu hotplug)
Date: Mon, 27 Feb 2017 21:35:49 +0100 [thread overview]
Message-ID: <20170227203549.GA6500@twins.programming.kicks-ass.net> (raw)
In-Reply-To: <1104576579.26276825.1488222387110.JavaMail.zimbra@redhat.com>
On Mon, Feb 27, 2017 at 02:06:27PM -0500, Paolo Bonzini wrote:
> > > + if (!boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
> > > + mark_tsc_unstable("not invariant");
> >
> > Errm, no.
> >
> > That makes TSC unusable for systems which do not go into C/P states in
> > which the TSC stops. There is a world outside KVM ....
>
> Actually I was surprised too by Peter's patch, as it was adding
> mark_tsc_unstable pretty much everywhere that didn't have nonstop TSC.
> But hopefully it would still be okay to call clear_sched_clock_stable
> in tsc_init, in the same way.
I was preserving the sched_clock behaviour. That said, maybe we can
simply remove all those extra checks and only rely on the current
mark_tsc_unstable() calls.
I'll just have to sit down and consider the various cases..
next prev parent reply other threads:[~2017-02-27 22:55 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-19 7:31 tip.today - scheduler bam boom crash (cpu hotplug) Mike Galbraith
2017-01-19 10:19 ` Peter Zijlstra
2017-01-19 11:39 ` Mike Galbraith
2017-01-19 13:36 ` Peter Zijlstra
2017-01-19 16:54 ` Ingo Molnar
2017-01-19 17:20 ` Peter Zijlstra
2017-01-19 20:35 ` sched/clock: Fix hotplug issue kbuild test robot
2017-01-19 20:37 ` kbuild test robot
2017-01-20 6:36 ` [tip:sched/core] sched/clock: Fix hotplug crash tip-bot for Peter Zijlstra
2017-02-27 12:30 ` tip.today - scheduler bam boom crash (cpu hotplug) Wanpeng Li
2017-02-27 12:35 ` Paolo Bonzini
2017-02-27 12:43 ` Peter Zijlstra
2017-02-27 12:50 ` Paolo Bonzini
2017-02-27 13:04 ` Peter Zijlstra
2017-02-27 15:27 ` Paolo Bonzini
2017-02-27 15:59 ` Peter Zijlstra
2017-02-27 16:11 ` Paolo Bonzini
2017-02-27 16:36 ` Peter Zijlstra
2017-02-27 17:27 ` Paolo Bonzini
2017-02-27 17:40 ` Thomas Gleixner
2017-02-27 19:06 ` Paolo Bonzini
2017-02-27 20:35 ` Peter Zijlstra [this message]
2017-02-28 1:51 ` Wanpeng Li
2017-02-28 8:08 ` Peter Zijlstra
2017-02-28 8:11 ` Wanpeng Li
2017-03-01 13:39 ` Wanpeng Li
2017-03-01 14:17 ` Peter Zijlstra
2017-02-27 13:48 ` Wanpeng Li
2017-02-27 14:05 ` Peter Zijlstra
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20170227203549.GA6500@twins.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=bp@alien8.de \
--cc=efault@gmx.de \
--cc=kernellwp@gmail.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mingo@elte.hu \
--cc=pbonzini@redhat.com \
--cc=tglx@linutronix.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.