From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:53245) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ZDS2S-0005qE-Ik for qemu-devel@nongnu.org; Fri, 10 Jul 2015 02:44:01 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ZDS2R-0004Zw-Ep for qemu-devel@nongnu.org; Fri, 10 Jul 2015 02:44:00 -0400 Date: Fri, 10 Jul 2015 14:43:50 +0800 From: Fam Zheng Message-ID: <20150710064350.GG31230@ad.nay.redhat.com> References: <1436413678-7114-1-git-send-email-famz@redhat.com> <20150709130208.GD11166@stefanha-thinkpad.redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20150709130208.GD11166@stefanha-thinkpad.redhat.com> Subject: Re: [Qemu-devel] [Qemu-block] [PATCH 0/3] mirror: Fix guest responsiveness during bitmap scan List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Stefan Hajnoczi Cc: Kevin Wolf , qemu-devel@nongnu.org, qemu-block@nongnu.org On Thu, 07/09 14:02, Stefan Hajnoczi wrote: > This patch only converts the mirror block job to use the new relax > function. The other block jobs (stream, backup, commit) are still using > a 0 ns delay and are therefore broken. They should probably be > converted in the same series. That's because they all can be perfectly mitigated by setting a reasonable "speed" that matchs the host horsepower. Thinking about this again, I doubt that lengthening the duration with a hardcoded value benifits everyone; and before Alexandre's reply on old server/slow disks, I don't recall any report, because the coroutines would already yield often enough, when waiting for IO to complete. So I am not sure whether they're broken in practice. Fam