[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH 4/6] tests: Add migration xbzrle test
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [Qemu-devel] [PATCH 4/6] tests: Add migration xbzrle test |
Date: |
Thu, 19 Oct 2017 10:06:15 +0100 |
User-agent: |
Mutt/1.9.1 (2017-09-22) |
* Juan Quintela (address@hidden) wrote:
> "Dr. David Alan Gilbert" <address@hidden> wrote:
> > * Juan Quintela (address@hidden) wrote:
> >> Signed-off-by: Juan Quintela <address@hidden>
>
> > +static void test_xbzrle(const char *uri)
> >> +{
> >> + QTestState *from, *to;
> >> +
> >> + test_migrate_start(&from, &to, uri);
> >> +
> >> + /* We want to pick a speed slow enough that the test completes
> >> + * quickly, but that it doesn't complete precopy even on a slow
> >> + * machine, so also set the downtime.
> >> + */
> >> + /* 100 ms */
> >> + migrate_set_parameter(from, "downtime-limit", "100");
> >> + /* 1MB/s slow*/
> >> + migrate_set_parameter(from, "max-bandwidth", "100000000");
> >> +
> >> + migrate_set_cache_size(from, "50000000");
> >
> > Why 50MB? I guess this is an interesting test; the program
> > dirties 100MB of RAM repeatedly, one byte/page. So 50MB is probably
> > not much use becuase it'll thrash.
>
> No good reason.
> What I want (tm):
> - if you have fast hardware, test is as fast as it can
> - if you don't have fast hardware (or very overloaded), it don't fail
>
> My current idea is:
> - using 1GB/s for speed
> - using downtime = 1ms when I want to wait for migration not converge
> - using downtime = 300ms when I want it to finish
>
> I am open to other numbers.
Well I was thinking if we could get it to not-converge unless
the xbzrle cache was large enough it would actually make sure we test
xbzrle; with a 50MB cache you wont test much of xbzrle because I think
it'll be rare to get a cache hit.
Dave
> >> + migrate_set_capability(from, "xbzrle", "true");
> >> + migrate_set_capability(to, "xbzrle", "true");
> >> + /* Wait for the first serial output from the source */
> >> + wait_for_serial("src_serial");
> >> +
> >> + migrate(from, uri);
> >> +
> >> + wait_for_migration_pass(from);
> >> +
> >> + /* 1GB/s now it should converge */
> >> + migrate_set_parameter(from, "max-bandwidth", "1000000000");
> >
> > I wonder about doing a set_cache_size 150MB here, with a delay before
> > the max-bandwidht? If we're lucky at 150MB it'll start actually using
> > the XBZRLE compression.
> >
> >> + if (!got_stop) {
> >> + qtest_qmp_eventwait(from, "STOP");
> >> + }
> >> + qtest_qmp_eventwait(to, "RESUME");
> >> +
> >> + wait_for_serial("dest_serial");
> >> + wait_for_migration_complete(from);
> >> +
> >> + test_migrate_end(from, to);
> >
> > Extract xbzrle stats?
>
> Thinking about that.
>
> I actually would want to test that when I set something, read it back
> that it is what I setted. I gues I would use a similar trick to what
> you do to get the pass number.
>
> Later, Juan.
--
Dr. David Alan Gilbert / address@hidden / Manchester, UK
- Re: [Qemu-devel] [PATCH 1/6] tests: Add basic migration precopy test, (continued)
Re: [Qemu-devel] [PATCH 1/6] tests: Add basic migration precopy test, Daniel P. Berrange, 2017/10/18
[Qemu-devel] [PATCH 4/6] tests: Add migration xbzrle test, Juan Quintela, 2017/10/04
[Qemu-devel] [PATCH 5/6] tests: Add migration compress threads tests, Juan Quintela, 2017/10/04
[Qemu-devel] [PATCH 6/6] tests: Move postcopy migration test to migrate-set-parameters, Juan Quintela, 2017/10/04
Re: [Qemu-devel] [PATCH 0/6] Add make check tests for Migration, no-reply, 2017/10/04