From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:38424) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fG4hV-000213-5q for qemu-devel@nongnu.org; Tue, 08 May 2018 11:38:51 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fG4hS-000626-VT for qemu-devel@nongnu.org; Tue, 08 May 2018 11:38:49 -0400 Received: from mx3-rdu2.redhat.com ([66.187.233.73]:52352 helo=mx1.redhat.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1fG4hS-00061s-R7 for qemu-devel@nongnu.org; Tue, 08 May 2018 11:38:46 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 517EDEB71C for ; Tue, 8 May 2018 15:38:46 +0000 (UTC) Date: Tue, 8 May 2018 16:38:40 +0100 From: "Dr. David Alan Gilbert" Message-ID: <20180508153838.GQ2500@work-vm> References: <20180425111940.1030-1-quintela@redhat.com> <20180425111940.1030-4-quintela@redhat.com> <20180503173154.GL2660@work-vm> <87sh726uvd.fsf@secure.laptop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <87sh726uvd.fsf@secure.laptop> Subject: Re: [Qemu-devel] [PATCH v8 3/8] 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 > >> Reviewed-by: Peter Xu > > >> + > >> + migrate_set_parameter(from, "xbzrle-cache-size", "33554432"); > > > > I still worry about the cache size relative to the size of memory we're > > actually changing in the test; I don't quite understand why it's turning > > out to get lots of hits. > > I planned this as a smorke test. But what value do you have in mind? Given the test code dirties 100MB of RAM, I suggest a cache of 110MB say. But it's interesting that the stats show we are getting a lot of page hits; I'm not sure I understand why. > > Also, xbzrle eats so much CPU we'll still have to watch out for the low > > end CPUs. > > Any concrete suggestion? > > My plan would have been to push on my next pull request: > > Add migration precopy test > Add migration xbzrle test > Migration ppc now inlines its program > > And put the rest of the patches with fixes for another review. Go with it and lets see; if we hit problems then we can just turn that 300ms downtime limit right up. Dave > > Later, Juan. -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK