From: Don Zickus <dzickus@redhat.com>
To: Andi Kleen <ak@linux.intel.com>
Cc: "Liang, Kan" <kan.liang@intel.com>,
Thomas Gleixner <tglx@linutronix.de>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"mingo@kernel.org" <mingo@kernel.org>,
"akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"babu.moger@oracle.com" <babu.moger@oracle.com>,
"atomlin@redhat.com" <atomlin@redhat.com>,
"prarit@redhat.com" <prarit@redhat.com>,
"torvalds@linux-foundation.org" <torvalds@linux-foundation.org>,
"peterz@infradead.org" <peterz@infradead.org>,
"eranian@google.com" <eranian@google.com>,
"acme@redhat.com" <acme@redhat.com>,
"stable@vger.kernel.org" <stable@vger.kernel.org>
Subject: Re: [PATCH V2] kernel/watchdog: fix spurious hard lockups
Date: Wed, 28 Jun 2017 15:00:08 -0400 [thread overview]
Message-ID: <20170628190008.3ftqq75evhn2hozp@redhat.com> (raw)
In-Reply-To: <20170627234822.GL23705@tassilo.jf.intel.com>
On Tue, Jun 27, 2017 at 04:48:22PM -0700, Andi Kleen wrote:
> > I haven't heard back any test result yet.
> >
> > The above patch looks good to me.
>
> This needs performance testing. It may slow down performance or latency sensitive workloads.
More motivation to work through the issues with the proposed real fix? :-)
>
> > Which workaround do you prefer, the above one or the one checking timestamp?
>
> I prefer the earlier patch, it has far less risk of performance issues.
But now you are slowing down the nmi_watchdog so much that the
watchdog_thresh hold becomes meaningless, no? (granted the turbo-mode blows
it out of the water too) So now folks who depend on the 10/5/1/whatever second
reliability lose that. I think that might be unfair too.
The hrtimer increase maintains that and just adds a few more
interrupts/second.
Cheers,
Don
next prev parent reply other threads:[~2017-06-28 19:00 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-21 14:41 [PATCH V2] kernel/watchdog: fix spurious hard lockups kan.liang
2017-06-21 15:12 ` Thomas Gleixner
2017-06-21 15:47 ` Liang, Kan
2017-06-21 17:40 ` Prarit Bhargava
2017-06-21 17:07 ` Andi Kleen
2017-06-21 19:59 ` Thomas Gleixner
2017-06-21 21:53 ` Thomas Gleixner
2017-06-22 15:33 ` Thomas Gleixner
2017-06-22 15:44 ` Don Zickus
2017-06-22 15:48 ` Liang, Kan
2017-06-23 8:01 ` Thomas Gleixner
2017-06-23 16:29 ` Don Zickus
2017-06-23 21:50 ` Thomas Gleixner
2017-06-26 20:19 ` Don Zickus
2017-06-26 20:30 ` Thomas Gleixner
2017-06-27 20:12 ` Don Zickus
2017-06-27 20:49 ` Liang, Kan
2017-06-27 21:09 ` Don Zickus
2017-06-27 23:48 ` Andi Kleen
2017-06-28 19:00 ` Don Zickus [this message]
2017-06-28 20:14 ` Andi Kleen
2017-06-29 15:44 ` Don Zickus
2017-06-29 16:12 ` Andi Kleen
2017-06-29 16:26 ` Don Zickus
2017-06-29 16:36 ` Andi Kleen
2017-07-17 1:24 ` Liang, Kan
2017-07-17 7:14 ` Thomas Gleixner
2017-07-17 12:18 ` Liang, Kan
2017-07-17 13:13 ` Thomas Gleixner
2017-07-17 14:46 ` Liang, Kan
2017-07-17 15:00 ` Thomas Gleixner
2017-07-17 14:46 ` Don Zickus
2017-08-15 1:16 ` Liang, Kan
2017-08-15 1:28 ` Linus Torvalds
2017-08-15 7:50 ` Thomas Gleixner
2017-08-17 15:45 ` Liang, Kan
2017-08-18 10:39 ` [tip:core/urgent] kernel/watchdog: Prevent false positives with turbo modes tip-bot for Thomas Gleixner
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