From: Keir Fraser <keir@xen.org>
To: Ian Campbell <ijc@hellion.org.uk>
Cc: "Philippe.Simonet@swisscom.com" <Philippe.Simonet@swisscom.com>,
"599161@bugs.debian.org" <599161@bugs.debian.org>,
"mrsanna1@gmail.com" <mrsanna1@gmail.com>,
"xen-devel@lists.xen.org" <xen-devel@lists.xen.org>
Subject: Re: #599161: Xen debug patch for the "clock shifts by 50 minutes" bug.
Date: Thu, 08 Nov 2012 14:34:46 +0000 [thread overview]
Message-ID: <CCC17386.51BA6%keir@xen.org> (raw)
In-Reply-To: <1352384924.12977.103.camel@hastur.hellion.org.uk>
On 08/11/2012 14:28, "Ian Campbell" <ijc@hellion.org.uk> wrote:
>>> There appears to be a certain amount of hardware-specificness to the
>>> issue -- so I'm wondering if maybe there are some platforms whose tsc is
>>> not as monotonically increasing as it needs to be...
>>
>> plt_* timestamps are not derived from TSC at all.
>
> I see, rather it is derived from the platform_timesource which could be
> HPET, pmtimer, pit etc but in this case (according to the provided xm
> dmesg) appears to be a 14MHz HPET.
>
> So I guess s/tsc/HPET/ in my original thought...
In fact plt_now and plt_wrap are both derived from the same value of
plt_stamp64. One is derived from it directly, and the other from
plt_stamp64+plt_mask+1 (== plt_stamp64+(1<<32)).
-- Keir
next prev parent reply other threads:[~2012-11-08 14:34 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1352375011.12977.95.camel@hastur.hellion.org.uk>
2012-11-08 12:54 ` #599161: Xen debug patch for the "clock shifts by 50 minutes" bug Keir Fraser
2012-11-08 14:28 ` Ian Campbell
2012-11-08 14:34 ` Keir Fraser [this message]
[not found] <CAE17a0XdxhaoCZaDDT6RXm1DPnabf2hWXAnzU5NukHeXX45grA@mail.gmail.com>
[not found] ` <CCCD845A.44DB0%keir.xen@gmail.com>
[not found] ` <CAE17a0Xit58cLiJ+pE7uKuCDq3Xn+7-5+iDpV2+5S+TX3yuT+Q@mail.gmail.com>
2012-11-26 10:20 ` Jan Beulich
2012-11-26 10:28 ` Mauro
2012-11-26 10:40 ` Ian Campbell
2012-11-26 12:18 ` Jan Beulich
2012-11-26 13:08 ` Philippe.Simonet
2012-11-26 14:15 ` Sylvain Munaut
2012-11-26 14:29 ` Jan Beulich
2012-11-07 10:10 Philippe.Simonet
2012-11-07 13:22 ` Ian Campbell
2012-11-07 17:40 ` Keir Fraser
2012-11-08 9:39 ` Jan Beulich
2012-11-08 10:38 ` Keir Fraser
2012-11-08 13:53 ` Jan Beulich
2012-11-08 14:04 ` Keir Fraser
2012-11-08 13:47 ` Philippe.Simonet
2012-11-08 14:29 ` Ian Campbell
2012-11-08 15:21 ` Mauro
[not found] ` <1352384968.12977.104.camel@hastur.hellion.org.uk>
2012-11-09 9:05 ` Philippe.Simonet
[not found] ` <FF93AF260AC2BB499A119CC65B092CF73151901D@sg000713.corproot.net>
2012-11-09 9:47 ` Jan Beulich
2012-11-09 9:54 ` Mauro
2012-11-13 10:14 ` Jan Beulich
2012-11-08 16:45 ` Tim Deegan
2012-11-08 16:53 ` Keir Fraser
2012-11-08 11:43 ` Ian Campbell
2012-11-08 14:20 ` Keir Fraser
2012-11-07 17:07 ` Jan Beulich
-- strict thread matches above, loose matches on Subject: below --
2012-10-26 12:59 Ian Campbell
2012-10-26 18:25 ` Mauro
[not found] ` <CAE17a0WfpKHxN=3iF6F+P0nT4UbyF9Lbpm8R5+JJEquQOmudXw@mail.gmail.com>
2012-10-26 18:40 ` Ian Campbell
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