Re: [Qemu-devel] [PATCH] migration: Increase default max_downtime from 30ms to 300ms

[Alexey Kardashevskiy]

On 03/27/2014 08:01 PM, Markus Armbruster wrote:
> Adding Juan.


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