mirror of https://lore.kernel.org/lkml/
 help / color / mirror / Atom feed
From: Thomas Gleixner <tglx@linutronix.de>
To: Andrew Lutomirski <luto@mit.edu>
Cc: "Borislav Petkov" <bp@amd64.org>,
	"Clemens Ladisch" <clemens@ladisch.de>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Ingo Molnar" <mingo@elte.hu>, "H. Peter Anvin" <hpa@zytor.com>,
	x86 <x86@kernel.org>, "Jörg Rödel" <joerg.roedel@amd.com>
Subject: Re: [FALSE ALARM] Re: HPET (?) related hangs and breakage in 2.6.35,36
Date: Wed, 10 Nov 2010 21:52:15 +0100 (CET)	[thread overview]
Message-ID: <alpine.LFD.2.00.1011102147580.2900@localhost6.localdomain6> (raw)
In-Reply-To: <AANLkTimNuSJz0nXZCR2zu963VQ_Y9R8ix73+QbbUy7nt@mail.gmail.com>

[-- Attachment #1: Type: TEXT/PLAIN, Size: 1190 bytes --]

On Wed, 10 Nov 2010, Andrew Lutomirski wrote:

> On Wed, Nov 10, 2010 at 1:50 PM, Borislav Petkov <bp@amd64.org> wrote:
> > On Wed, Nov 10, 2010 at 01:48:00PM -0500, Andrew Lutomirski wrote:
> >> > Clocksource: tsc unstable (delta = -34355296774 ns)
> >> > Switching: to clocksource hpet
> >>
> >> Please disregard -- this is a bug in nouveau (or drm) not hpet.  I'll
> >> send a bug report to the maintainers.
> >
> > Interesting! Joerg was complaining about similar symptoms with .36 today
> > too.
> 
> Well, there is a clocksource sort-of-bug that could cause confusion:
> when something totally unrelated to clocksources goes out to lunch,
> the clocksource watchdog decides that the clocksource is unstable and
> complains, steering everyone toward filing the wrong bug.

How should the clocksource watchdog code know that something went to
lunch? The fact that we need to monitor TSC at all is horrible enough,
adding further heuristics to detect extended lunch breaks would be
just a PITA.

Maybe we could print a different warning when we see large negative
deltas, which is the main indicator for the system being stuck for
quite a time while TSC advances happily.

Thanks,

	tglx

  reply	other threads:[~2010-11-10 20:52 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-11-09 13:46 Andrew Lutomirski
2010-11-09 15:20 ` Clemens Ladisch
2010-11-09 15:38   ` Borislav Petkov
2010-11-09 17:44     ` Andrew Lutomirski
2010-11-09 18:01       ` Borislav Petkov
2010-11-09 21:29         ` Andrew Lutomirski
2010-11-10 18:48           ` [FALSE ALARM] " Andrew Lutomirski
2010-11-10 18:50             ` Borislav Petkov
2010-11-10 19:02               ` Andrew Lutomirski
2010-11-10 20:52                 ` Thomas Gleixner [this message]
2010-11-10 20:56                   ` Andrew Lutomirski
2010-11-10 20:58                     ` Thomas Gleixner
2010-11-11 11:06               ` Roedel, Joerg

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=alpine.LFD.2.00.1011102147580.2900@localhost6.localdomain6 \
    --to=tglx@linutronix.de \
    --cc=bp@amd64.org \
    --cc=clemens@ladisch.de \
    --cc=hpa@zytor.com \
    --cc=joerg.roedel@amd.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=luto@mit.edu \
    --cc=mingo@elte.hu \
    --cc=peterz@infradead.org \
    --cc=x86@kernel.org \
    /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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox

all inboxes | Powered by JetHome®