From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56133) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e56mY-00063v-54 for qemu-devel@nongnu.org; Thu, 19 Oct 2017 05:06:27 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1e56mU-0002tn-Th for qemu-devel@nongnu.org; Thu, 19 Oct 2017 05:06:26 -0400 Received: from mx1.redhat.com ([209.132.183.28]:45050) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1e56mU-0002tA-K1 for qemu-devel@nongnu.org; Thu, 19 Oct 2017 05:06:22 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id AE1661B5E48 for ; Thu, 19 Oct 2017 09:06:21 +0000 (UTC) Date: Thu, 19 Oct 2017 10:06:15 +0100 From: "Dr. David Alan Gilbert" Message-ID: <20171019090615.GB2281@work-vm> References: <20171004103933.7898-1-quintela@redhat.com> <20171004103933.7898-5-quintela@redhat.com> <20171016160735.GF2252@work-vm> <8760bcmzyo.fsf@secure.laptop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8760bcmzyo.fsf@secure.laptop> Subject: Re: [Qemu-devel] [PATCH 4/6] tests: Add migration xbzrle test List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Juan Quintela Cc: qemu-devel@nongnu.org, lvivier@redhat.com, peterx@redhat.com * Juan Quintela (quintela@redhat.com) wrote: > "Dr. David Alan Gilbert" wrote: > > * Juan Quintela (quintela@redhat.com) wrote: > >> Signed-off-by: Juan Quintela > > > +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 / dgilbert@redhat.com / Manchester, UK