From nobody Sat Apr 27 15:05:02 2024 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zoho.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org; Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1495231230413369.36755546589166; Fri, 19 May 2017 15:00:30 -0700 (PDT) Received: from localhost ([::1]:60397 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dBpwi-0002r3-1U for importer@patchew.org; Fri, 19 May 2017 18:00:28 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:58002) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dBpvp-0002Tt-9U for qemu-devel@nongnu.org; Fri, 19 May 2017 17:59:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dBpvm-0003Zi-81 for qemu-devel@nongnu.org; Fri, 19 May 2017 17:59:33 -0400 Received: from [62.254.189.133] (port=52428 helo=centos.localdomain) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dBpvl-0003P2-Sz for qemu-devel@nongnu.org; Fri, 19 May 2017 17:59:30 -0400 Received: by centos.localdomain (Postfix, from userid 500) id 6DB8D9FD42; Fri, 19 May 2017 22:59:04 +0100 (BST) From: Felipe Franciosi To: Juan Quintela , "Jason J. Herne" Date: Fri, 19 May 2017 22:59:02 +0100 Message-Id: <1495231142-19055-1-git-send-email-felipe@nutanix.com> X-Mailer: git-send-email 1.9.5 X-detected-operating-system: by eggs.gnu.org: Mac OS X [generic] [fuzzy] X-Received-From: 62.254.189.133 Subject: [Qemu-devel] [PATCH] migration: keep bytes_xfer_prev init'd to zero 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: "qemu-devel@nongnu.org" , Felipe Franciosi Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" The first time migration_bitmap_sync() is called, bytes_xfer_prev is set to ram_state.bytes_transferred which is, at this point, zero. The next time migration_bitmap_sync() is called, an iteration has happened and bytes_xfer_prev is set to 'x' bytes. Most likely, more than one second has passed, so the auto converge logic will be triggered and bytes_xfer_now will also be set to 'x' bytes. This condition is currently masked by dirty_rate_high_cnt, which will wait for a few iterations before throttling. It would otherwise always assume zero bytes have been copied and therefore throttle the guest (possibly) prematurely. Given bytes_xfer_prev is only used by the auto convergence logic, it makes sense to only set its value after a check has been made against bytes_xfer_now. Signed-off-by: Felipe Franciosi ~ --- migration/ram.c | 4 ---- 1 file changed, 4 deletions(-) diff --git a/migration/ram.c b/migration/ram.c index f59fdd4..793af39 100644 --- a/migration/ram.c +++ b/migration/ram.c @@ -670,10 +670,6 @@ static void migration_bitmap_sync(RAMState *rs) =20 rs->bitmap_sync_count++; =20 - if (!rs->bytes_xfer_prev) { - rs->bytes_xfer_prev =3D ram_bytes_transferred(); - } - if (!rs->time_last_bitmap_sync) { rs->time_last_bitmap_sync =3D qemu_clock_get_ms(QEMU_CLOCK_REALTIM= E); } --=20 1.9.5