Re: [Qemu-devel] [PATCH 1/8] migration: stop compressing page in migration thread

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Xiao Guangrong (guangrong.xiao@gmail.com) wrote:
> 
> Hi David,
> 
> Thanks for your review.
> 
> On 03/15/2018 06:25 PM, Dr. David Alan Gilbert wrote:
> 
> > >   migration/ram.c | 32 ++++++++++++++++----------------
> > 
> > Hi,
> >    Do you have some performance numbers to show this helps?  Were those
> > taken on a normal system or were they taken with one of the compression
> > accelerators (which I think the compression migration was designed for)?
> 
> Yes, i have tested it on my desktop, i7-4790 + 16G, by locally live migrate
> the VM which has 8 vCPUs + 6G memory and the max-bandwidth is limited to 350.
> 
> During the migration, a workload which has 8 threads repeatedly written total
> 6G memory in the VM. Before this patchset, its bandwidth is ~25 mbps, after
> applying, the bandwidth is ~50 mbps.

OK, that's good - worth adding those notes to your cover letter.
I wonder how well it works with compression acceleration hardware; I
can't see anything in this series making it worse.

> BTW, Compression will use almost all valid bandwidth after all of our work
> which i will post it out part by part.

Oh, that will be very nice.

Dave

--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK