Re: [Qemu-devel] [RFC PATCH v5 0/4] Separate thread for VM migration

[Umesh Deshpande <udeshpan@redhat.com>]

Jitterd Test
I ran jitterd in a migrating VM of size 8GB with and w/o the patch series.
./jitterd -f -m 1 -p 100 -r 40
That is to report the jitter of greater than 400ms during the interval 
of 40 seconds.

Jitter in ms. with the migration thread.
Run    Total (Peak)
1        No chatter
2        No chatter
3        No chatter
4        409 (360)

Jitter in ms. without migration thread.
Run    Total (Peak)
1        4663 (2413)
2        643 (423)
3        1973 (1817)
4        3908 (3772)

--------------------------------------------------------------
Flood ping test : ping to the migrating VM from a third machine (data 
over 3 runs)
Latency (ms) ping to a non-migrating VM    : Avg 0.156, Max: 0.96
Latency (ms) with migration thread             : Avg 0.215, Max: 280
Latency (ms) without migration thread        : Avg 6.47,   Max: 4562

- Umesh


On 08/24/2011 01:19 PM, Anthony Liguori wrote:
> On 08/23/2011 10:12 PM, Umesh Deshpande wrote:
>> Following patch series deals with VCPU and iothread starvation during 
>> the
>> migration of a guest. Currently the iothread is responsible for 
>> performing the
>> guest migration. It holds qemu_mutex during the migration and doesn't 
>> allow VCPU
>> to enter the qemu mode and delays its return to the guest. The guest 
>> migration,
>> executed as an iohandler also delays the execution of other iohandlers.
>> In the following patch series,
>
> Can you please include detailed performance data with and without this 
> series?
>
> Perhaps runs of migration with jitterd running in the guest.
>
> Regards,
>
> Anthony Liguori
>
>>
>> The migration has been moved to a separate thread to
>> reduce the qemu_mutex contention and iohandler starvation.
>>
>> Umesh Deshpande (4):
>>    MRU ram block list
>>    migration thread mutex
>>    separate migration bitmap
>>    separate migration thread
>>
>>   arch_init.c         |   38 ++++++++++++----
>>   buffered_file.c     |   75 +++++++++++++++++--------------
>>   cpu-all.h           |   42 +++++++++++++++++
>>   exec.c              |   97 ++++++++++++++++++++++++++++++++++++++--
>>   migration.c         |  122 
>> +++++++++++++++++++++++++++++---------------------
>>   migration.h         |    9 ++++
>>   qemu-common.h       |    2 +
>>   qemu-thread-posix.c |   10 ++++
>>   qemu-thread.h       |    1 +
>>   savevm.c            |    5 --
>>   10 files changed, 297 insertions(+), 104 deletions(-)
>>
>