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Re: [Qemu-devel] [PATCH] migration: Increase default max_downtime from 3
From: |
Alexey Kardashevskiy |
Subject: |
Re: [Qemu-devel] [PATCH] migration: Increase default max_downtime from 30ms to 300ms |
Date: |
Wed, 30 Apr 2014 11:10:11 +1000 |
User-agent: |
Mozilla/5.0 (X11; Linux i686 on x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 |
On 04/13/2014 12:38 AM, Alexey Kardashevskiy wrote:
> On 03/27/2014 08:01 PM, Markus Armbruster wrote:
>> Adding Juan.
>
>
> Ping?
Ping?
>
>>
>> Alexey Kardashevskiy <address@hidden> writes:
>>
>>> The existing timeout is 30ms which on 100MB/s (1Gbit) gives us
>>> 3MB/s rate maximum. If we put some load on the guest, it is easy to
>>> get page dirtying rate too big so live migration will never complete.
>>> In the case of libvirt that means that the guest will be stopped
>>> anyway after a timeout specified in the "virsh migrate" command and
>>> this normally generates even bigger delay.
>>>
>>> This changes max_downtime to 300ms which seems to be more
>>> reasonable value.
>>>
>>> Signed-off-by: Alexey Kardashevskiy <address@hidden>
>>> ---
>>> migration.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/migration.c b/migration.c
>>> index e0e24d4..02bbce9 100644
>>> --- a/migration.c
>>> +++ b/migration.c
>>> @@ -144,7 +144,7 @@ void process_incoming_migration(QEMUFile *f)
>>> * the choice of nanoseconds is because it is the maximum resolution that
>>> * get_clock() can achieve. It is an internal measure. All user-visible
>>> * units must be in seconds */
>>> -static uint64_t max_downtime = 30000000;
>>> +static uint64_t max_downtime = 300000000;
>>>
>>> uint64_t migrate_max_downtime(void)
>>> {
>
>
--
Alexey