From: Zachary Amsden <zamsden@redhat.com>
To: Marcelo Tosatti <mtosatti@redhat.com>
Cc: kvm@vger.kernel.org, Avi Kivity <avi@redhat.com>
Subject: Re: KVM timekeeping and TSC virtualization
Date: Tue, 24 Aug 2010 18:04:57 -1000 [thread overview]
Message-ID: <4C749669.9050204@redhat.com> (raw)
In-Reply-To: <20100824221301.GA12173@amt.cnet>
On 08/24/2010 12:13 PM, Marcelo Tosatti wrote:
> On Thu, Aug 19, 2010 at 10:07:14PM -1000, Zachary Amsden wrote:
>
>> This patch set implements full TSC virtualization, with both
>> trapping and passthrough modes, and intelligent mode switching.
>> As a result, TSC will never go backwards, we are stable against
>> guest re-calibration attempts, VM reset, and migration. For guests
>> which require it, the TSC khz can even be preserved on migration
>> to a new host.
>>
>> The TSC will never be trapped on UP systems unless the host TSC
>> actually runs faster than the guest; other conditions, including
>> bad hardware and changing speeds are accomodated by using catchup
>> mode to keep the guest passthrough TSC in line with the host clock.
>>
>> What is still needed on top of this is a way to force TSC
>> trapping, or disable it entirely, for benchmarking purposes.
>> I refrained from adding that last bit because it wasn't clear
>> whether the best thing to do is a global 'force TSC trapping' /
>> 'force TSC passthrough' / 'intelligent choice', or if this control
>> should be on a per-VM level, via an ioctl(), module parameter,
>> or sysfs.
>>
>> John and Thomas I have cc'd on this because it may be relevant to
>> their interests and I always appreciate feedback, especially on
>> a change set as large and complex as this.
>>
>> Enjoy. This time, there are no howler monkeys. I've included
>> all the feedback I got from previous rounds of this and more.
>>
> Applied 1-19, thanks.
>
>
Great, thanks. I'll wait for more feedback on the rest and rebase.
prev parent reply other threads:[~2010-08-25 4:05 UTC|newest]
Thread overview: 106+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-20 8:07 KVM timekeeping and TSC virtualization Zachary Amsden
2010-08-20 8:07 ` [KVM timekeeping 01/35] Drop vm_init_tsc Zachary Amsden
2010-08-20 16:54 ` Glauber Costa
2010-08-20 8:07 ` [KVM timekeeping 02/35] Convert TSC writes to TSC offset writes Zachary Amsden
2010-08-20 8:07 ` [KVM timekeeping 03/35] Move TSC offset writes to common code Zachary Amsden
2010-08-20 17:06 ` Glauber Costa
2010-08-24 0:51 ` Zachary Amsden
2010-08-20 8:07 ` [KVM timekeeping 04/35] Fix SVM VMCB reset Zachary Amsden
2010-08-20 8:07 ` [KVM timekeeping 05/35] Move TSC reset out of vmcb_init Zachary Amsden
2010-08-20 17:08 ` Glauber Costa
2010-08-24 0:52 ` Zachary Amsden
2010-08-20 8:07 ` [KVM timekeeping 06/35] TSC reset compensation Zachary Amsden
2010-08-20 8:07 ` [KVM timekeeping 07/35] Make cpu_tsc_khz updates use local CPU Zachary Amsden
2010-08-20 8:07 ` [KVM timekeeping 08/35] Warn about unstable TSC Zachary Amsden
2010-08-20 17:28 ` Glauber Costa
2010-08-24 0:56 ` Zachary Amsden
2010-08-20 8:07 ` [KVM timekeeping 09/35] Unify TSC logic Zachary Amsden
2010-08-20 8:07 ` [KVM timekeeping 10/35] Fix deep C-state TSC desynchronization Zachary Amsden
2010-08-20 17:30 ` Glauber Costa
2010-09-14 9:10 ` Jan Kiszka
2010-09-14 9:27 ` Avi Kivity
2010-09-14 10:40 ` Jan Kiszka
2010-09-14 10:47 ` Avi Kivity
2010-09-14 19:32 ` Zachary Amsden
2010-09-14 22:26 ` Jan Kiszka
2010-09-14 23:40 ` Zachary Amsden
2010-09-15 5:34 ` Jan Kiszka
2010-09-15 7:55 ` Avi Kivity
2010-09-15 8:04 ` Jan Kiszka
2010-09-15 12:29 ` Glauber Costa
2010-09-15 4:07 ` Zachary Amsden
2010-09-15 8:09 ` Jan Kiszka
2010-09-15 12:32 ` Glauber Costa
2010-09-15 18:27 ` Jan Kiszka
2010-09-17 22:09 ` Zachary Amsden
2010-09-17 22:31 ` Zachary Amsden
2010-09-18 23:53 ` Zachary Amsden
2010-08-20 8:07 ` [KVM timekeeping 11/35] Add helper functions for time computation Zachary Amsden
2010-08-20 17:34 ` Glauber Costa
2010-08-24 0:58 ` Zachary Amsden
2010-08-20 8:07 ` [KVM timekeeping 12/35] Robust TSC compensation Zachary Amsden
2010-08-20 17:40 ` Glauber Costa
2010-08-24 1:01 ` Zachary Amsden
2010-08-24 21:33 ` Daniel Verkamp
2010-08-20 8:07 ` [KVM timekeeping 13/35] Perform hardware_enable in CPU_STARTING callback Zachary Amsden
2010-08-27 16:32 ` Jan Kiszka
2010-08-27 23:43 ` Zachary Amsden
2010-08-30 9:10 ` Jan Kiszka
2010-08-20 8:07 ` [KVM timekeeping 14/35] Add clock sync request to hardware enable Zachary Amsden
2010-08-20 8:07 ` [KVM timekeeping 15/35] Move scale_delta into common header Zachary Amsden
2010-08-20 8:07 ` [KVM timekeeping 16/35] Fix a possible backwards warp of kvmclock Zachary Amsden
2011-09-02 18:34 ` Philipp Hahn
2011-09-05 14:06 ` [BUG, PATCH-2.6.32] " Philipp Hahn
2011-09-12 11:32 ` Marcelo Tosatti
2010-08-20 8:07 ` [KVM timekeeping 17/35] Implement getnsboottime kernel API Zachary Amsden
2010-08-20 18:39 ` john stultz
2010-08-20 23:37 ` Zachary Amsden
2010-08-21 0:02 ` john stultz
2010-08-21 0:52 ` Zachary Amsden
2010-08-21 1:04 ` john stultz
2010-08-21 1:22 ` Zachary Amsden
2010-08-27 18:05 ` Jan Kiszka
2010-08-27 23:48 ` Zachary Amsden
2010-08-30 18:07 ` Jan Kiszka
2010-08-20 8:07 ` [KVM timekeeping 18/35] Use getnsboottime in KVM Zachary Amsden
2010-08-20 8:07 ` [KVM timekeeping 19/35] Add timekeeping documentation Zachary Amsden
2010-08-20 17:50 ` Glauber Costa
2010-08-20 8:07 ` [KVM timekeeping 20/35] Make math work for other scales Zachary Amsden
2010-08-20 8:07 ` [KVM timekeeping 21/35] Track max tsc_khz Zachary Amsden
2010-08-20 8:07 ` [KVM timekeeping 22/35] Track tsc last write in vcpu Zachary Amsden
2010-08-20 8:07 ` [KVM timekeeping 23/35] Set initial TSC rate conversion factors Zachary Amsden
2010-08-20 8:07 ` [KVM timekeeping 24/35] Timer request function renaming Zachary Amsden
2010-08-20 8:07 ` [KVM timekeeping 25/35] Add clock catchup mode Zachary Amsden
2010-08-25 17:27 ` Marcelo Tosatti
2010-08-25 20:48 ` Zachary Amsden
2010-08-25 22:01 ` Marcelo Tosatti
2010-08-25 23:38 ` Glauber Costa
2010-08-26 0:17 ` Zachary Amsden
2010-08-20 8:07 ` [KVM timekeeping 26/35] Catchup slower TSC to guest rate Zachary Amsden
2010-09-07 3:44 ` Dong, Eddie
2010-09-07 22:14 ` Zachary Amsden
2010-08-20 8:07 ` [KVM timekeeping 27/35] Add TSC trapping Zachary Amsden
2010-08-20 8:07 ` [KVM timekeeping 28/35] Unstable TSC write compensation Zachary Amsden
2010-08-20 8:07 ` [KVM timekeeping 29/35] TSC overrun protection Zachary Amsden
2010-08-20 8:07 ` [KVM timekeeping 30/35] IOCTL for setting TSC rate Zachary Amsden
2010-08-20 17:56 ` Glauber Costa
2010-08-21 16:11 ` Arnd Bergmann
2010-08-20 8:07 ` [KVM timekeeping 31/35] Exit conditions for TSC trapping Zachary Amsden
2010-08-20 8:07 ` [KVM timekeeping 32/35] Entry " Zachary Amsden
2010-08-20 8:07 ` [KVM timekeeping 33/35] Indicate reliable TSC in kvmclock Zachary Amsden
2010-08-20 17:45 ` Glauber Costa
2010-08-24 1:14 ` Zachary Amsden
2010-08-20 8:07 ` [KVM timekeeping 34/35] Remove dead code Zachary Amsden
2010-08-20 8:07 ` [KVM timekeeping 35/35] Add some debug stuff Zachary Amsden
2010-08-20 13:26 ` KVM timekeeping and TSC virtualization David S. Ahern
2010-08-20 23:24 ` Zachary Amsden
2010-08-22 1:32 ` David S. Ahern
2010-08-24 1:44 ` Zachary Amsden
2010-08-24 3:04 ` David S. Ahern
2010-08-24 5:47 ` Zachary Amsden
2010-08-24 13:32 ` David S. Ahern
2010-08-24 23:01 ` Zachary Amsden
2010-08-25 16:55 ` Marcelo Tosatti
2010-08-25 20:32 ` Zachary Amsden
2010-08-24 22:13 ` Marcelo Tosatti
2010-08-25 4:04 ` Zachary Amsden [this message]
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