From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga09.intel.com ([134.134.136.24]:18968 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752260AbbJXQIS (ORCPT ); Sat, 24 Oct 2015 12:08:18 -0400 Message-ID: <562BACE8.8070507@intel.com> Date: Sun, 25 Oct 2015 00:08:08 +0800 From: "Lan, Tianyu" MIME-Version: 1.0 To: "Michael S. Tsirkin" CC: bhelgaas@google.com, carolyn.wyborny@intel.com, donald.c.skidmore@intel.com, eddie.dong@intel.com, nrupal.jani@intel.com, yang.z.zhang@intel.com, agraf@suse.de, kvm@vger.kernel.org, pbonzini@redhat.com, qemu-devel@nongnu.org, emil.s.tantilov@intel.com, intel-wired-lan@lists.osuosl.org, jeffrey.t.kirsher@intel.com, jesse.brandeburg@intel.com, john.ronciak@intel.com, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, matthew.vick@intel.com, mitch.a.williams@intel.com, netdev@vger.kernel.org, shannon.nelson@intel.com Subject: Re: [RFC Patch 08/12] IXGBEVF: Rework code of finding the end transmit desc of package References: <1445445464-5056-1-git-send-email-tianyu.lan@intel.com> <1445445464-5056-9-git-send-email-tianyu.lan@intel.com> <20151022155650-mutt-send-email-mst@redhat.com> In-Reply-To: <20151022155650-mutt-send-email-mst@redhat.com> Content-Type: text/plain; charset=windows-1252; format=flowed Sender: linux-pci-owner@vger.kernel.org List-ID: On 10/22/2015 8:58 PM, Michael S. Tsirkin wrote: > Do you really need to play the shifting games? > Can't you just reset everything and re-initialize the rings? > It's slower but way less intrusive. > Also removes the need to track writes into rings. Shift ring is to avoid losing those packets in the ring. This may cause some race condition and so I introduced a lock to prevent such cases in the latter patch. Yes, reset everything after migration can make thing easy. But just like you said it would affect performance and loss more packets. I can do a test later to get data about these two way.