Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754499AbbHFDqx (ORCPT ); Wed, 5 Aug 2015 23:46:53 -0400 Received: from mga11.intel.com ([192.55.52.93]:56202 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751867AbbHFDqw convert rfc822-to-8bit (ORCPT ); Wed, 5 Aug 2015 23:46:52 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.15,622,1432623600"; d="scan'208";a="620229325" From: "Li, Liang Z" To: Paolo Bonzini , "'Juan Quintela'" , "linux-kernel@vger.kernel.org" CC: "Zhang, Yang Z" , "kvm@vger.kernel.org" Subject: about the time consuming kvm_vcpu_ioctl issue in rhel kernel Thread-Topic: about the time consuming kvm_vcpu_ioctl issue in rhel kernel Thread-Index: AdDP9UJwwpuw8Ol+QP2Z1DthOfo0aw== Date: Thu, 6 Aug 2015 03:46:47 +0000 Message-ID: Accept-Language: zh-CN, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.239.127.40] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 712 Lines: 12 Hi Paolo & Juan, I found some of the kvm_vcpu_ioctl operation takes about more than 10ms with the 3.10.0-229.el7.x86_64 kernel, which prolong the VM service downtime when doing live migration about 20~30ms. This happened when doing the KVM_KVMCLOCK_CTRL ioctl. It's worse if more VCPUs used by guest(4VPUs in my test). The upstream kernel does not have this issue because of the patch 7a72f7a140bfd3, maybe this patch should be backported to the el7 kernel. Liang -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/