From patchwork Tue Jul 12 09:36:15 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Denis V. Lunev" X-Patchwork-Id: 9224879 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 6824360572 for ; Tue, 12 Jul 2016 09:37:00 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 57CEE27D5D for ; Tue, 12 Jul 2016 09:37:00 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4C9F527EED; Tue, 12 Jul 2016 09:37:00 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 51DCA27D5D for ; Tue, 12 Jul 2016 09:36:58 +0000 (UTC) Received: from localhost ([::1]:38666 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bMu7d-0003og-Gf for patchwork-qemu-devel@patchwork.kernel.org; Tue, 12 Jul 2016 05:36:57 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:56777) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bMu7N-0003oZ-Tf for qemu-devel@nongnu.org; Tue, 12 Jul 2016 05:36:42 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bMu7J-0001MX-7q for qemu-devel@nongnu.org; Tue, 12 Jul 2016 05:36:41 -0400 Received: from mailhub.sw.ru ([195.214.232.25]:15107 helo=relay.sw.ru) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bMu7I-0001J6-Rv for qemu-devel@nongnu.org; Tue, 12 Jul 2016 05:36:37 -0400 Received: from irbis.sw.ru ([10.24.38.119]) by relay.sw.ru (8.13.4/8.13.4) with ESMTP id u6AG44Oi013425; Sun, 10 Jul 2016 19:04:06 +0300 (MSK) From: "Denis V. Lunev" To: qemu-block@nongnu.org, qemu-devel@nongnu.org Date: Tue, 12 Jul 2016 12:36:15 +0300 Message-Id: <1468316175-11522-1-git-send-email-den@openvz.org> X-Mailer: git-send-email 2.1.4 X-detected-operating-system: by eggs.gnu.org: OpenBSD 3.x X-Received-From: 195.214.232.25 Subject: [Qemu-devel] [PATCH 1/1] mirror: double performance of the bulk stage if the disc is full X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Kevin Wolf , Vladimir Sementsov-Ogievskiy , Fam Zheng , Jeff Cody , Max Reitz , Stefan Hajnoczi , den@openvz.org Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP From: Vladimir Sementsov-Ogievskiy Mirror can do up to 16 in-flight requests, but actually on full copy (the whole source disk is non-zero) in-flight is always 1. This happens as the request is not limited in size: the data occupies maximum available capacity of s->buf. The patch limits the size of the request to some artificial constant (1 Mb here), which is not that big or small. This effectively enables back parallelism in mirror code as it was designed. The result is important: the time to migrate 10 Gb disk is reduced from ~350 sec to 170 sec. Signed-off-by: Vladimir Sementsov-Ogievskiy Signed-off-by: Denis V. Lunev CC: Stefan Hajnoczi CC: Fam Zheng CC: Kevin Wolf CC: Max Reitz CC: Jeff Cody CC: Eric Blake Reviewed-by: Paolo Bonzini --- block/mirror.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/block/mirror.c b/block/mirror.c index 4fe127e..53d3bcd 100644 --- a/block/mirror.c +++ b/block/mirror.c @@ -23,7 +23,9 @@ #define SLICE_TIME 100000000ULL /* ns */ #define MAX_IN_FLIGHT 16 -#define DEFAULT_MIRROR_BUF_SIZE (10 << 20) +#define MAX_IO_SECTORS ((1 << 20) >> BDRV_SECTOR_BITS) /* 1 Mb */ +#define DEFAULT_MIRROR_BUF_SIZE \ + (MAX_IN_FLIGHT * MAX_IO_SECTORS * BDRV_SECTOR_SIZE) /* The mirroring buffer is a list of granularity-sized chunks. * Free chunks are organized in a list. @@ -387,7 +389,9 @@ static uint64_t coroutine_fn mirror_iteration(MirrorBlockJob *s) nb_chunks * sectors_per_chunk, &io_sectors, &file); if (ret < 0) { - io_sectors = nb_chunks * sectors_per_chunk; + io_sectors = MIN(nb_chunks * sectors_per_chunk, MAX_IO_SECTORS); + } else if (ret & BDRV_BLOCK_DATA) { + io_sectors = MIN(io_sectors, MAX_IO_SECTORS); } io_sectors -= io_sectors % sectors_per_chunk;