From: "Marcin Gibuła" <m.gibula@beyond.pl>
To: Alexander Graf <agraf@suse.de>
Cc: "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>,
"kvm@vger.kernel.org" <kvm@vger.kernel.org>
Subject: Re: [Qemu-devel] [PATCH] kvmclock: Ensure time in migration never goes backward
Date: Mon, 05 May 2014 20:26:04 +0200 [thread overview]
Message-ID: <5367D7BC.2040705@beyond.pl> (raw)
In-Reply-To: <E3A99F7C-3347-449D-AB91-0456435D4BD6@suse.de>
>> is it possible to have kvmclock jumping forward?
>>
>> Because I've reproducible case when at about 1 per 20 vm restores, VM freezes for couple of hours and then resumes with date few hundreds years ahead. Happens only with kvmclock.
>>
>> And this patch seems to fix very similar issue so maybe it's all the same bug.
>
> I'm fairly sure it is the exact same bug. Jumping backward is like jumping forward by a biiiiig amount :)
Hi,
I've tested your path on my test VM... don't know if it's pure luck or
not, but it didn't hang with over 70 restores.
The message "KVM Clock migrated backwards, using later time" fires every
time, but VM is healthy after resume.
--
mg
next prev parent reply other threads:[~2014-05-05 18:26 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-05 13:51 [Qemu-devel] [PATCH] kvmclock: Ensure time in migration never goes backward Alexander Graf
2014-05-05 17:46 ` Marcin Gibuła
2014-05-05 18:05 ` Alexander Graf
2014-05-05 18:26 ` Marcin Gibuła [this message]
2014-05-05 23:27 ` Marcelo Tosatti
2014-05-05 23:31 ` Marcelo Tosatti
2014-05-06 8:07 ` Marcin Gibuła
2014-05-06 7:11 ` Alexander Graf
2014-05-06 7:37 ` Marcin Gibuła
2014-05-05 23:23 ` Marcelo Tosatti
2014-05-05 23:31 ` Marcelo Tosatti
2014-05-06 7:18 ` Alexander Graf
2014-05-06 19:54 ` Marcin Gibuła
2014-05-07 23:23 ` Marcelo Tosatti
2014-05-07 23:21 ` Marcelo Tosatti
2014-05-07 23:29 ` Alexander Graf
2014-05-06 7:16 ` Alexander Graf
2014-05-07 10:04 ` Nick Thomas
2014-05-08 1:33 ` Marcelo Tosatti
2014-05-08 7:21 ` Alexander Graf
2014-05-09 2:28 ` Marcelo Tosatti
2014-05-09 11:53 ` Paolo Bonzini
2014-05-12 20:26 ` Alexander Graf
2014-05-14 7:26 ` Marcelo Tosatti
2014-05-14 6:47 ` Marcelo Tosatti
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5367D7BC.2040705@beyond.pl \
--to=m.gibula@beyond.pl \
--cc=agraf@suse.de \
--cc=kvm@vger.kernel.org \
--cc=qemu-devel@nongnu.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).