From: "David S. Ahern" <daahern@cisco.com>
To: gleb@redhat.com
Cc: qemu-devel@nongnu.org
Subject: Re: [Qemu-devel] [RESEND][PATCH 0/3] Fix guest time drift under heavy load.
Date: Thu, 06 Nov 2008 10:28:44 -0700 [thread overview]
Message-ID: <4913294C.3040105@cisco.com> (raw)
In-Reply-To: <49119551.2070704@redhat.com>
Dor Laor wrote:
> Gleb Natapov wrote:
>> On Fri, Oct 31, 2008 at 02:17:19PM -0500, Anthony Liguori wrote:
>>
>>> Gleb Natapov wrote:
>>>
>>>> Qemu device emulation for timers might be inaccurate and
>>>> causes coalescing of several IRQs into one. It happens when the
>>>> load on the host is high and the guest did not manage to ack the
>>>> previous IRQ. The problem can be reproduced by copying of a big
>>>> file or many small ones inside Windows guest. When you do that guest
>>>> clock start to lag behind the host one.
<snip>
>>
>>
>>> How do
>>> Linux guests behave with this?
>>>
>> Linux guests don't use pit or RTC for time keeping. They are completely
>> unaffected by those patches.
>>
>>
> It will probably also drift with clock=pit in the guest kernel cmdline.
It is my understanding that for linux guests using a 2.4 kernel (e.g.,
RHEL3) the PIT is the only option.
david
next prev parent reply other threads:[~2008-11-06 17:28 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-10-29 15:22 [Qemu-devel] [RESEND][PATCH 0/3] Fix guest time drift under heavy load Gleb Natapov
2008-10-29 15:22 ` [Qemu-devel] [PATCH 1/3] Change qemu_set_irq() to return status information Gleb Natapov
2008-10-29 15:22 ` [Qemu-devel] [PATCH 2/3] Fix time drift problem under high load when PIT is in use Gleb Natapov
2008-10-29 15:22 ` [Qemu-devel] [PATCH 3/3] Fix time drift problem under high load when RTC " Gleb Natapov
2008-11-05 12:46 ` Dor Laor
2008-10-31 19:17 ` [Qemu-devel] [RESEND][PATCH 0/3] Fix guest time drift under heavy load Anthony Liguori
2008-11-02 13:04 ` Gleb Natapov
2008-11-05 12:45 ` Dor Laor
2008-11-05 15:48 ` andrzej zaborowski
2008-11-05 16:33 ` Anthony Liguori
2008-11-06 7:16 ` Gleb Natapov
2008-11-06 9:37 ` andrzej zaborowski
2008-11-06 10:08 ` Gleb Natapov
2008-11-06 13:21 ` andrzej zaborowski
2008-11-06 14:18 ` Gleb Natapov
2008-11-06 14:35 ` andrzej zaborowski
2008-11-06 15:04 ` Gleb Natapov
2008-11-06 15:41 ` Anthony Liguori
2008-11-07 23:18 ` andrzej zaborowski
2008-11-08 8:23 ` Gleb Natapov
2008-11-06 13:44 ` Paul Brook
2008-11-05 17:43 ` Gleb Natapov
2008-11-06 17:28 ` David S. Ahern [this message]
2008-11-05 16:43 ` Anthony Liguori
2008-11-06 3:55 ` Jamie Lokier
2008-11-06 8:12 ` Gleb Natapov
2008-11-06 14:10 ` Anthony Liguori
2008-11-06 14:24 ` Paul Brook
2008-11-06 14:40 ` Anthony Liguori
2008-11-06 14:51 ` Gleb Natapov
2008-11-06 15:37 ` Anthony Liguori
2008-11-08 8:36 ` Gleb Natapov
2008-11-08 22:14 ` Dor Laor
2008-11-09 7:40 ` Gleb Natapov
2008-11-09 16:38 ` Anthony Liguori
2008-11-09 21:00 ` Avi Kivity
2008-11-09 16:36 ` Anthony Liguori
2008-11-10 14:37 ` Gleb Natapov
2008-11-10 15:24 ` Anthony Liguori
2008-11-10 15:29 ` Gleb Natapov
2008-11-10 15:46 ` Anthony Liguori
2008-11-10 15:51 ` Gleb Natapov
2008-11-11 14:43 ` Gleb Natapov
2008-11-11 17:26 ` Anthony Liguori
2008-11-11 20:17 ` Anthony Liguori
2008-11-12 11:42 ` Gleb Natapov
2008-11-12 11:54 ` Glauber Costa
2008-11-12 12:38 ` Dor Laor
2008-11-06 3:41 ` Jamie Lokier
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