From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paolo Bonzini Subject: Re: [PATCH] virtio-scsi: replace target spinlock with seqcount Date: Fri, 23 May 2014 15:59:52 +0200 Message-ID: <537F5458.6010008@redhat.com> References: <1400851712-26731-1-git-send-email-ming.lei@canonical.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mx1.redhat.com ([209.132.183.28]:38258 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750981AbaEWOAS (ORCPT ); Fri, 23 May 2014 10:00:18 -0400 In-Reply-To: <1400851712-26731-1-git-send-email-ming.lei@canonical.com> Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Ming Lei , "James E.J. Bottomley" Cc: linux-scsi@vger.kernel.org, Christoph Hellwig , Wanlong Gao , Rusty Russell Il 23/05/2014 15:28, Ming Lei ha scritto: > The spinlock of tgt_lock is only for serializing read and write > req_vq, one lockless seqcount is enough for the purpose. > > On one 16core VM with vhost-scsi backend, the patch can improve > IOPS with 3% on random read test. Nice. :) The patch looks good, thanks for working this out! James, I have a couple more patches planned for virtio-scsi, so I'll send out the update next week. Paolo