From: Anthony Liguori <anthony@codemonkey.ws>
To: Juan Quintela <quintela@redhat.com>
Cc: Avi Kivity <avi@redhat.com>, qemu-devel@nongnu.org
Subject: [Qemu-devel] Re: [PATCH 10/10] Maintaing number of dirty pages
Date: Wed, 01 Dec 2010 09:55:23 -0600 [thread overview]
Message-ID: <4CF66FEB.7030602@codemonkey.ws> (raw)
In-Reply-To: <m3lj49xzhp.fsf@trasno.mitica>
On 12/01/2010 09:51 AM, Juan Quintela wrote:
> Avi Kivity<avi@redhat.com> wrote:
>
>> On 11/30/2010 04:46 PM, Juan Quintela wrote:
>>
>>> Anthony Liguori<anthony@codemonkey.ws> wrote:
>>>
>>>> On 11/23/2010 05:03 PM, Juan Quintela wrote:
>>>>
>>>>> From: Juan Quintela<quintela@trasno.org>
>>>>>
>>>>> Calculate the number of dirty pages takes a lot on hosts with lots
>>>>> of memory. Just maintain how many pages are dirty. Only sync bitmaps
>>>>> if number is small enough.
>>>>>
>>>>>
>>>> There needs to be numbers that justify this as part of the commit message.
>>>>
>>> They are on patch 0/6.
>>>
>>> Additionally, with 64GB of RAM, this bitmap is HUGE, having to walk over
>>> it in each ram_save_live() call is too onerous.
>>>
>> It's not so huge. It's scaled down by a factor of 8 * 4096 = 32K. So
>> it's a 2MB bitmap. If kept as a bitmap and accessed in longs, it can
>> be read in less than a millisecond.
BTW, by this logic, even a 1-byte dirty bitmap is only 16mb which can be
read in less than 16ms so where is the reported 24 minute stall coming from?
Regards,
Anthony Liguori
next prev parent reply other threads:[~2010-12-01 15:57 UTC|newest]
Thread overview: 75+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-23 23:02 [Qemu-devel] [PATCH 00/10] Fix migration with lots of memory Juan Quintela
2010-11-23 23:02 ` [Qemu-devel] [PATCH 01/10] Add spent time to migration Juan Quintela
2010-11-23 23:02 ` [Qemu-devel] [PATCH 02/10] Add buffered_file_internal constant Juan Quintela
2010-11-24 10:40 ` [Qemu-devel] " Michael S. Tsirkin
2010-11-24 10:52 ` Juan Quintela
2010-11-24 11:04 ` Michael S. Tsirkin
2010-11-24 11:13 ` Juan Quintela
2010-11-24 11:19 ` Michael S. Tsirkin
[not found] ` <4CF46012.2060804@codemonkey.ws>
2010-11-30 11:56 ` Juan Quintela
2010-11-30 14:02 ` Anthony Liguori
2010-11-30 14:11 ` Michael S. Tsirkin
2010-11-30 14:22 ` Anthony Liguori
2010-11-30 15:40 ` Juan Quintela
2010-11-30 16:10 ` Michael S. Tsirkin
2010-11-30 16:32 ` Juan Quintela
2010-11-30 16:44 ` Anthony Liguori
2010-11-30 18:04 ` Juan Quintela
2010-11-30 18:54 ` Anthony Liguori
2010-11-30 19:15 ` Juan Quintela
2010-11-30 20:23 ` Anthony Liguori
2010-11-30 20:56 ` Juan Quintela
2010-11-23 23:03 ` [Qemu-devel] [PATCH 03/10] Add printf debug to savevm Juan Quintela
[not found] ` <4CF45AB2.7050506@codemonkey.ws>
2010-11-30 10:36 ` Stefan Hajnoczi
2010-11-30 22:40 ` [Qemu-devel] " Juan Quintela
2010-12-01 7:50 ` Stefan Hajnoczi
2010-11-23 23:03 ` [Qemu-devel] [PATCH 04/10] No need to iterate if we already are over the limit Juan Quintela
2010-11-23 23:03 ` [Qemu-devel] [PATCH 05/10] KVM don't care about TLB handling Juan Quintela
2010-11-23 23:03 ` [Qemu-devel] [PATCH 06/10] Only calculate expected_time for stage 2 Juan Quintela
2010-11-23 23:03 ` [Qemu-devel] [PATCH 07/10] ram_save_remaining() returns an uint64_t Juan Quintela
[not found] ` <4CF45C0C.705@codemonkey.ws>
2010-11-30 7:21 ` [Qemu-devel] " Paolo Bonzini
2010-11-30 13:44 ` Anthony Liguori
2010-11-30 14:38 ` Juan Quintela
2010-11-23 23:03 ` [Qemu-devel] [PATCH 08/10] Count nanoseconds with uint64_t not doubles Juan Quintela
2010-11-30 7:17 ` [Qemu-devel] " Paolo Bonzini
[not found] ` <4CF45C5B.9080507@codemonkey.ws>
2010-11-30 14:40 ` Juan Quintela
2010-11-23 23:03 ` [Qemu-devel] [PATCH 09/10] Exit loop if we have been there too long Juan Quintela
2010-11-24 10:40 ` [Qemu-devel] " Michael S. Tsirkin
2010-11-24 11:01 ` Juan Quintela
2010-11-24 11:14 ` Michael S. Tsirkin
2010-11-24 15:16 ` Paolo Bonzini
2010-11-24 15:59 ` Michael S. Tsirkin
[not found] ` <4CF45E3F.4040609@codemonkey.ws>
2010-11-30 8:10 ` Paolo Bonzini
2010-11-30 13:26 ` Juan Quintela
[not found] ` <4CF45D67.5010906@codemonkey.ws>
2010-11-30 7:15 ` Paolo Bonzini
2010-11-30 13:47 ` Anthony Liguori
2010-11-30 13:58 ` Avi Kivity
2010-11-30 14:17 ` Anthony Liguori
2010-11-30 14:27 ` Avi Kivity
2010-11-30 14:50 ` Anthony Liguori
2010-12-01 12:40 ` Avi Kivity
2010-11-30 17:43 ` Juan Quintela
2010-12-01 1:20 ` Takuya Yoshikawa
2010-12-01 1:52 ` Juan Quintela
2010-12-01 2:22 ` Takuya Yoshikawa
2010-12-01 12:35 ` Avi Kivity
2010-12-01 13:45 ` Juan Quintela
2010-12-02 1:31 ` Takuya Yoshikawa
2010-12-02 8:37 ` Avi Kivity
2010-11-30 14:12 ` Paolo Bonzini
2010-11-30 15:00 ` Anthony Liguori
2010-11-30 17:59 ` Juan Quintela
2010-11-23 23:03 ` [Qemu-devel] [PATCH 10/10] Maintaing number of dirty pages Juan Quintela
[not found] ` <4CF45DE0.8020701@codemonkey.ws>
2010-11-30 14:46 ` [Qemu-devel] " Juan Quintela
2010-12-01 14:46 ` Avi Kivity
2010-12-01 15:51 ` Juan Quintela
2010-12-01 15:55 ` Anthony Liguori [this message]
2010-12-01 16:25 ` Juan Quintela
2010-12-01 16:33 ` Anthony Liguori
2010-12-01 16:43 ` Avi Kivity
2010-12-01 16:49 ` Anthony Liguori
2010-12-01 16:52 ` Avi Kivity
2010-12-01 16:56 ` Anthony Liguori
2010-12-01 17:01 ` Avi Kivity
2010-12-01 17:05 ` Anthony Liguori
2010-12-01 18:51 ` Juan Quintela
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