From: Thomas Gleixner <tglx@linutronix.de>
To: Mike Surcouf <mps.surcouf.lkml@gmail.com>
Cc: Thomas Shao <huishao@microsoft.com>,
Richard Cochran <richardcochran@gmail.com>,
Jeff Epler <jepler@unpythonic.net>,
"gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>,
LKML <linux-kernel@vger.kernel.org>,
"devel@linuxdriverproject.org" <devel@linuxdriverproject.org>,
"olaf@aepfle.de" <olaf@aepfle.de>,
"apw@canonical.com" <apw@canonical.com>,
"jasowang@redhat.com" <jasowang@redhat.com>,
KY Srinivasan <kys@microsoft.com>,
John Stultz <john.stultz@linaro.org>,
Richard Cochran <rcochran@linutronix.de>
Subject: Re: [PATCH v2 1/2] timekeeping: add EXPORT_SYMBOL_GPL for do_adjtimex()
Date: Wed, 22 Oct 2014 14:42:09 +0200 (CEST) [thread overview]
Message-ID: <alpine.DEB.2.11.1410221441370.5308@nanos> (raw)
In-Reply-To: <CAL7Bo8EUcmUXhpJvrz_G-Svs+GwSF9CQec5oWWQSYBqWiJYH2w@mail.gmail.com>
On Wed, 22 Oct 2014, Mike Surcouf wrote:
> I get that NTP can be installed locally. This is how I regulate time
> on my guests. I agree the admin argument probably doesn't stand up.
>
> The problem is hyperv_clocksource (pluggable time source used by
> hyperv guests) is systematically fast in my environment. by around
> -250 PPM.
> I get away with NTP (just).
> However others have had to use tickadj to get hyperv_clocksource close
> enough for NTP to work i.e. inside +/-500 PPM. (This IS outside normal
> admin tasks)
>
> So if we are going to use NTP as the solution for hyperv guests (which
> is a valid one) the systematic drift of hyperv_clocksource in
> different environments will need to be addressed. Maybe this patch
> could be modified to tune the tick count on boot before NTP starts and
> then leave it alone so NTP can take over.
How about fixing hyperv_clocksource in the first place?
Thanks,
tglx
next prev parent reply other threads:[~2014-10-22 12:42 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-15 8:39 Thomas Shao
2014-10-20 18:28 ` Thomas Gleixner
2014-10-20 18:40 ` Thomas Gleixner
2014-10-21 3:18 ` Thomas Shao
2014-10-21 3:24 ` John Stultz
2014-10-21 4:08 ` Thomas Shao
2014-10-21 8:23 ` Thomas Gleixner
2014-10-21 4:02 ` Jeff Epler
2014-10-21 4:55 ` Thomas Shao
2014-10-21 8:25 ` Thomas Gleixner
2014-10-21 8:20 ` Richard Cochran
2014-10-21 10:11 ` Thomas Shao
2014-10-22 11:01 ` Mike Surcouf
2014-10-22 12:42 ` Thomas Gleixner [this message]
2014-10-22 13:51 ` Thomas Shao
2014-10-22 14:20 ` Mike Surcouf
2014-10-21 8:13 ` Richard Cochran
2014-10-21 9:16 ` Thomas Shao
2014-10-21 8:19 ` Thomas Gleixner
2014-10-21 9:02 ` Thomas Shao
2014-10-21 2:37 ` Thomas Shao
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