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From: Jan Beulich <jbeulich@suse.com>
To: Andreas Kinzler <hfp@posteo.de>
Cc: xen-devel@lists.xenproject.org
Subject: Re: [Xen-devel] wall clock drift on Coffee Lake / C24x mainboard (HPET broken?), best practices
Date: Tue, 19 Nov 2019 15:44:04 +0100	[thread overview]
Message-ID: <fefdc7a3-c76e-2596-c296-6c1025ab917d@suse.com> (raw)
In-Reply-To: <3d021741-17eb-4d88-9628-23170ce38b0c@posteo.de>

On 19.11.2019 15:31, Andreas Kinzler wrote:
> On 19.11.2019 10:29, Jan Beulich wrote:
>> Now would you be up to checking whether, rather than via BIOS
>> settings (which not all BIOSes may offer) the same can be
>> achieved by using Xen's command line option "max_cstate="?
>> Also did you check whether further limiting C state use would
> 
> I cannot try on production machines. I may have a slot on lab machines 
> but I cannot promise.
> 
>  > further improve the situation? And did you possibly also check
>  > whether telling Xen not to use the HPET would make a difference?
> 
> Which other clocksource do you prefer? Is Xen tested (field-proven) on 
> that other clocksource?

"acpi" (i.e. the PM timer) ought to be fine. That's what Xen was
primarily using before HPET became commonly exposed by the ACPI
tables. "tsc" ought to be fine too on single-socket systems.

Jan

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      reply	other threads:[~2019-11-19 14:44 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-12 18:47 [Xen-devel] wall clock drift on C24x mainboard, best practices Andreas Kinzler
2019-11-13 23:10 ` [Xen-devel] wall clock drift on Coffee Lake / C24x mainboard (HPET broken?), " Andreas Kinzler
2019-11-14 11:29   ` Jan Beulich
2019-11-15 11:01     ` Andreas Kinzler
2019-11-18 19:35       ` Andreas Kinzler
2019-11-19  9:29         ` Jan Beulich
2019-11-19 14:31           ` Andreas Kinzler
2019-11-19 14:44             ` Jan Beulich [this message]

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