From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 67357C55185 for ; Thu, 23 Apr 2020 01:49:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 41AC52071C for ; Thu, 23 Apr 2020 01:49:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="YD3HQliY" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726396AbgDWBtG (ORCPT ); Wed, 22 Apr 2020 21:49:06 -0400 Received: from us-smtp-2.mimecast.com ([205.139.110.61]:35874 "EHLO us-smtp-delivery-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726002AbgDWBtG (ORCPT ); Wed, 22 Apr 2020 21:49:06 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1587606545; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=/Yq3gVavrIWjxtPSiTvUpzdhbDuTm1Ve5hdpLPT2nCg=; b=YD3HQliYJkB5nSTNugy7fnxkpw9kGgm9LsHN1zZ2cJwQmKcBi6CV5ZSYUtEcgBv8FHWmRx IswzAvSnnxVfQZ84S3kkZnsJQk7Y/AkPk9p5r1d+2UsGcX7Of7h55jD+/EHfRoT39ACs2P Xa1oJeDFL3TR2RleDA9OEKlPON1hj2M= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-458-t-D1Bt7rP-CM8oFX6SkaBA-1; Wed, 22 Apr 2020 21:49:01 -0400 X-MC-Unique: t-D1Bt7rP-CM8oFX6SkaBA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 5B2871800D6B; Thu, 23 Apr 2020 01:48:59 +0000 (UTC) Received: from T590 (ovpn-8-30.pek2.redhat.com [10.72.8.30]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 087836084B; Thu, 23 Apr 2020 01:48:52 +0000 (UTC) Date: Thu, 23 Apr 2020 09:48:48 +0800 From: Ming Lei To: James Bottomley Cc: linux-scsi@vger.kernel.org, "Martin K . Petersen" , Bart Van Assche , Christoph Hellwig , John Garry Subject: Re: [PATCH V2] scsi: put hot fields of scsi_host_template into one cacheline Message-ID: <20200423014848.GA331623@T590> References: <20200422095425.319674-1-ming.lei@redhat.com> <1587566490.3485.7.camel@HansenPartnership.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1587566490.3485.7.camel@HansenPartnership.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org On Wed, Apr 22, 2020 at 07:41:30AM -0700, James Bottomley wrote: > On Wed, 2020-04-22 at 17:54 +0800, Ming Lei wrote: > > The following three fields of scsi_host_template are referenced in > > scsi IO submission path, so put them together into one cacheline: > > > > - cmd_size > > - queuecommand > > - commit_rqs > > Are there benchmarks to show this actually makes a difference, if so, > how much? Originally I observed 40% IOPS boost on scsi_debug by moving the three fields into scsi_host, but I lost that test environment now. When I run fio on scsi_debug in another machine, IOPS gets ~10% boost with this patch. Thanks, Ming