From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34418) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fkv6k-0007cy-KE for qemu-devel@nongnu.org; Wed, 01 Aug 2018 13:40:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fkv6j-0004Ka-G1 for qemu-devel@nongnu.org; Wed, 01 Aug 2018 13:40:22 -0400 Date: Wed, 1 Aug 2018 18:40:05 +0100 From: "Dr. David Alan Gilbert" Message-ID: <20180801174005.GD2691@work-vm> References: <20180626135035.133432-1-vsementsov@virtuozzo.com> <20180626135035.133432-5-vsementsov@virtuozzo.com> <700dffe4-f3a8-8f70-052c-9f6f8ffbe3d3@redhat.com> <20180801102031.GC2691@work-vm> <64aad02b-3d5c-70d6-0f5a-93dd5b88e4bc@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <64aad02b-3d5c-70d6-0f5a-93dd5b88e4bc@redhat.com> Subject: Re: [Qemu-devel] [PATCH 4/6] dirty-bitmaps: clean-up bitmaps loading and migration logic List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: John Snow Cc: Vladimir Sementsov-Ogievskiy , qemu-devel@nongnu.org, qemu-block@nongnu.org, quintela@redhat.com, stefanha@redhat.com, famz@redhat.com, mreitz@redhat.com, kwolf@redhat.com, den@openvz.org, Eric Blake * John Snow (jsnow@redhat.com) wrote: > > > On 08/01/2018 06:20 AM, Dr. David Alan Gilbert wrote: > > * John Snow (jsnow@redhat.com) wrote: > > > > > > > >> I'd rather do something like this: > >> - Always flush bitmaps to disk on inactivate. > > > > Does that increase the time taken by the inactivate measurably? > > If it's small relative to everything else that's fine; it's just I > > always worry a little since I think this happens after we've stopped the > > CPU on the source, so is part of the 'downtime'. > > > > Dave > > -- > > Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK > > > > I'm worried that if we don't, we're leaving behind unusable, partially > complete files behind us. That's a bad design and we shouldn't push for > it just because it's theoretically faster. Oh I don't care about theoretical speed; but if it's actually unusably slow in practice then it needs fixing. Dave > --js -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK