From: Marcelo Tosatti <mtosatti@redhat.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: Eduardo Habkost <ehabkost@redhat.com>,
David Matlack <dmatlack@google.com>,
Peter Hornyack <peterhornyack@google.com>,
KVM list <kvm@vger.kernel.org>
Subject: Re: TSC deadline timer in guests vs. migration?
Date: Mon, 4 Jul 2016 16:30:08 -0300 [thread overview]
Message-ID: <20160704193005.GA28201@amt.cnet> (raw)
In-Reply-To: <759376f0-e0bf-e53a-99e4-598bf14547e3@redhat.com>
On Mon, Jul 04, 2016 at 01:01:42PM +0200, Paolo Bonzini wrote:
> Can bad things happen if a guest using the TSC deadline timer is
> migrated? The guest doesn't re-calibrate the TSC after migration, and
> the TSC frequency can and will change unless your data center is
> perfectly homogeneous.
It can fire earlier if the destination runs at a higher frequency.
It will fire past the configured time if the destination runs at a slower frequency.
Suppose the first case is worse.
Should convert the expiration time to nanoseconds i suppose, and then
convert back on the destination.
next prev parent reply other threads:[~2016-07-04 19:30 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-04 11:01 TSC deadline timer in guests vs. migration? Paolo Bonzini
2016-07-04 19:07 ` Eduardo Habkost
2016-07-05 10:48 ` Paolo Bonzini
2016-07-04 19:30 ` Marcelo Tosatti [this message]
2016-07-04 19:45 ` Eduardo Habkost
2016-07-04 20:17 ` Paolo Bonzini
2016-07-05 12:51 ` Marcelo Tosatti
2016-07-05 13:04 ` Eduardo Habkost
2016-07-05 13:34 ` Paolo Bonzini
2016-07-05 18:11 ` Eduardo Habkost
2016-07-05 21:40 ` Paolo Bonzini
2016-07-05 22:12 ` Eduardo Habkost
2016-07-06 6:01 ` Paolo Bonzini
2016-07-05 20:39 ` Marcelo Tosatti
2016-07-05 21:41 ` Paolo Bonzini
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