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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Mon, 20 May 2019 21:44:28 +0100 Received: from b01ledav005.gho.pok.ibm.com (b01ledav005.gho.pok.ibm.com [9.57.199.110]) by b01cxnp22035.gho.pok.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x4KKiRwj37814502 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 20 May 2019 20:44:27 GMT Received: from b01ledav005.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 6BB06AE064; Mon, 20 May 2019 20:44:27 +0000 (GMT) Received: from b01ledav005.gho.pok.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id E1657AE05F; Mon, 20 May 2019 20:44:25 +0000 (GMT) Received: from maxibm.ibmuc.com (unknown [9.85.147.231]) by b01ledav005.gho.pok.ibm.com (Postfix) with ESMTP; Mon, 20 May 2019 20:44:25 +0000 (GMT) From: "Maxiwell S. Garcia" To: qemu-devel@nongnu.org Date: Mon, 20 May 2019 17:43:39 -0300 X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 19052020-0052-0000-0000-000003C3BBB5 X-IBM-SpamModules-Scores: X-IBM-SpamModules-Versions: BY=3.00011132; HX=3.00000242; KW=3.00000007; PH=3.00000004; SC=3.00000286; SDB=6.01206188; UDB=6.00633353; IPR=6.00987147; MB=3.00026975; MTD=3.00000008; XFM=3.00000015; UTC=2019-05-20 20:44:29 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19052020-0053-0000-0000-000060FA118A Message-Id: <20190520204340.832-1-maxiwell@linux.ibm.com> X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-05-20_08:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=574 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1905200129 X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [generic] X-Received-From: 148.163.156.1 Subject: [Qemu-devel] [PATCH 0/1] spapr: Do not re-read the clock on pre_save handler on migration 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-ppc@nongnu.org, "Maxiwell S. Garcia" , david@gibson.dropbear.id.au Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" I suggest to remove the pre_save handler that saves the timebase before migrate. The commit that added this was ported from x86: 6053a86fe7bd: kvmclock: reduce kvmclock difference on migration The review [1] had a discussion about it. The author says that a VM already paused 10 minutes ago should re-read the clock just before migrate. But a reviewer question was not answered: "Is it really valid to make the clock move on an already-paused VM, only because it was migrated?" This clock move makes the guest know about the pause between the stop and migrate commands. Many side effects could happen after migration. [1] http://lists.nongnu.org/archive/html/qemu-devel/2016-12/msg00610.html Maxiwell S. Garcia (1): spapr: Do not re-read the clock on pre_save handler on migration hw/ppc/ppc.c | 24 ------------------------ 1 file changed, 24 deletions(-) -- 2.20.1