From: Thomas Gleixner <tglx@linutronix.de>
To: Feng Tang <feng.tang@intel.com>, "Paul E. McKenney" <paulmck@kernel.org>
Cc: Xing Zhengjun <zhengjun.xing@linux.intel.com>,
John Stultz <john.stultz@linaro.org>,
Stephen Boyd <sboyd@kernel.org>, Jonathan Corbet <corbet@lwn.net>,
Mark Rutland <Mark.Rutland@arm.com>,
Marc Zyngier <maz@kernel.org>, Andi Kleen <ak@linux.intel.com>,
Chris Mason <clm@fb.com>, LKML <linux-kernel@vger.kernel.org>,
lkp@lists.01.org, lkp@intel.com
Subject: Re: [LKP] Re: [clocksource] 6c52b5f3cf: stress-ng.opcode.ops_per_sec -14.4% regression
Date: Mon, 26 Apr 2021 14:39:25 +0200 [thread overview]
Message-ID: <87pmyhte2q.ffs@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20210424122920.GB85095@shbuild999.sh.intel.com>
On Sat, Apr 24 2021 at 20:29, Feng Tang wrote:
> On Fri, Apr 23, 2021 at 07:02:54AM -0700, Paul E. McKenney wrote:
> And I'm eager to know if there is any real case of an unreliable tsc
> on the 'large numbers' of x86 system which complies with our cpu feature
> check. And if there is, my 2/2 definitely should be dropped.
Nothing prevents BIOS tinkerers from trying to be 'smart'. My most
recent encounter (3 month ago) was on a laptop where TSC drifted off on
CPU0 very slowly, but was caught due to the TSC_ADJUST check in idle.
I'm still thinking about a solution to avoid that extra timer and the
watchdog for these systems, but haven't found anything which I don't
hate with a passion yet.
Thanks,
tglx
WARNING: multiple messages have this Message-ID (diff)
From: Thomas Gleixner <tglx@linutronix.de>
To: lkp@lists.01.org
Subject: Re: [clocksource] 6c52b5f3cf: stress-ng.opcode.ops_per_sec -14.4% regression
Date: Mon, 26 Apr 2021 14:39:25 +0200 [thread overview]
Message-ID: <87pmyhte2q.ffs@nanos.tec.linutronix.de> (raw)
In-Reply-To: <20210424122920.GB85095@shbuild999.sh.intel.com>
[-- Attachment #1: Type: text/plain, Size: 740 bytes --]
On Sat, Apr 24 2021 at 20:29, Feng Tang wrote:
> On Fri, Apr 23, 2021 at 07:02:54AM -0700, Paul E. McKenney wrote:
> And I'm eager to know if there is any real case of an unreliable tsc
> on the 'large numbers' of x86 system which complies with our cpu feature
> check. And if there is, my 2/2 definitely should be dropped.
Nothing prevents BIOS tinkerers from trying to be 'smart'. My most
recent encounter (3 month ago) was on a laptop where TSC drifted off on
CPU0 very slowly, but was caught due to the TSC_ADJUST check in idle.
I'm still thinking about a solution to avoid that extra timer and the
watchdog for these systems, but haven't found anything which I don't
hate with a passion yet.
Thanks,
tglx
next prev parent reply other threads:[~2021-04-26 12:39 UTC|newest]
Thread overview: 54+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-20 6:49 [clocksource] 6c52b5f3cf: stress-ng.opcode.ops_per_sec -14.4% regression kernel test robot
2021-04-20 6:49 ` kernel test robot
2021-04-20 13:43 ` Paul E. McKenney
2021-04-20 13:43 ` Paul E. McKenney
2021-04-20 14:05 ` Paul E. McKenney
2021-04-20 14:05 ` Paul E. McKenney
2021-04-21 6:07 ` [LKP] " Xing, Zhengjun
2021-04-21 6:07 ` Xing, Zhengjun
2021-04-21 13:42 ` [LKP] " Paul E. McKenney
2021-04-21 13:42 ` Paul E. McKenney
2021-04-22 6:58 ` [LKP] " Xing Zhengjun
2021-04-22 6:58 ` Xing Zhengjun
2021-04-22 7:41 ` [LKP] " Feng Tang
2021-04-22 7:41 ` Feng Tang
2021-04-22 14:24 ` [LKP] " Paul E. McKenney
2021-04-22 14:24 ` Paul E. McKenney
2021-04-22 16:57 ` [LKP] " Paul E. McKenney
2021-04-22 16:57 ` Paul E. McKenney
2021-04-23 6:11 ` [LKP] " Feng Tang
2021-04-23 6:11 ` Feng Tang
2021-04-23 14:02 ` [LKP] " Paul E. McKenney
2021-04-23 14:02 ` Paul E. McKenney
2021-04-24 12:29 ` [LKP] " Feng Tang
2021-04-24 12:29 ` Feng Tang
2021-04-24 17:53 ` [LKP] " Paul E. McKenney
2021-04-24 17:53 ` Paul E. McKenney
2021-04-25 2:14 ` [LKP] " Feng Tang
2021-04-25 2:14 ` Feng Tang
2021-04-25 3:14 ` [LKP] " Feng Tang
2021-04-25 3:14 ` Feng Tang
2021-04-25 19:15 ` [LKP] " Paul E. McKenney
2021-04-25 19:15 ` Paul E. McKenney
2021-04-25 19:14 ` [LKP] " Paul E. McKenney
2021-04-25 19:14 ` Paul E. McKenney
2021-04-26 12:39 ` Thomas Gleixner [this message]
2021-04-26 12:39 ` Thomas Gleixner
2021-04-26 14:05 ` [LKP] " Feng Tang
2021-04-26 14:05 ` Feng Tang
2021-04-26 14:33 ` [LKP] " Thomas Gleixner
2021-04-26 14:33 ` Thomas Gleixner
2021-04-26 15:12 ` [LKP] " Feng Tang
2021-04-26 15:12 ` Feng Tang
2021-04-23 2:15 ` [LKP] " Xing Zhengjun
2021-04-23 2:15 ` Xing Zhengjun
2021-04-23 4:12 ` [LKP] " Paul E. McKenney
2021-04-23 4:12 ` Paul E. McKenney
2021-04-23 19:14 ` [LKP] " Thomas Gleixner
2021-04-23 19:14 ` Thomas Gleixner
2021-04-23 21:14 ` [LKP] " Paul E. McKenney
2021-04-23 21:14 ` Paul E. McKenney
2021-04-23 23:39 ` [LKP] " Paul E. McKenney
2021-04-23 23:39 ` Paul E. McKenney
2021-04-23 19:09 ` [LKP] " Thomas Gleixner
2021-04-23 19:09 ` Thomas Gleixner
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