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=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_2 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 A7852C55185 for ; Wed, 22 Apr 2020 14:41:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 85DE120724 for ; Wed, 22 Apr 2020 14:41:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=hansenpartnership.com header.i=@hansenpartnership.com header.b="lYJklvgu"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=hansenpartnership.com header.i=@hansenpartnership.com header.b="lYJklvgu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726355AbgDVOld (ORCPT ); Wed, 22 Apr 2020 10:41:33 -0400 Received: from bedivere.hansenpartnership.com ([66.63.167.143]:57652 "EHLO bedivere.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725810AbgDVOlc (ORCPT ); Wed, 22 Apr 2020 10:41:32 -0400 Received: from localhost (localhost [127.0.0.1]) by bedivere.hansenpartnership.com (Postfix) with ESMTP id 57E2F8EE19C; Wed, 22 Apr 2020 07:41:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=hansenpartnership.com; s=20151216; t=1587566492; bh=JpvkGBcMoi/nwM6TimRHNVqLYdLfv1Jl1MKwS+sPS0M=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=lYJklvguqxm4JPPHjcg8zANe4tg8U+xHydcByA9LgS1pci9SEiYiKud7f0IjUUHZv Im7qcM4HX9Xr0zjMRZYCl2QRt9f9Oni4LhLlKQpZ2JEqjruwYO0vykh8NEG8ZLmHZL WZ5T27IfD/C06D1g6147qARt+EAs1Ki+HOg21JzM= Received: from bedivere.hansenpartnership.com ([127.0.0.1]) by localhost (bedivere.hansenpartnership.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id JndJ_a63X6UU; Wed, 22 Apr 2020 07:41:32 -0700 (PDT) Received: from [153.66.254.194] (unknown [50.35.76.230]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by bedivere.hansenpartnership.com (Postfix) with ESMTPSA id B381A8EE0CE; Wed, 22 Apr 2020 07:41:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=hansenpartnership.com; s=20151216; t=1587566492; bh=JpvkGBcMoi/nwM6TimRHNVqLYdLfv1Jl1MKwS+sPS0M=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=lYJklvguqxm4JPPHjcg8zANe4tg8U+xHydcByA9LgS1pci9SEiYiKud7f0IjUUHZv Im7qcM4HX9Xr0zjMRZYCl2QRt9f9Oni4LhLlKQpZ2JEqjruwYO0vykh8NEG8ZLmHZL WZ5T27IfD/C06D1g6147qARt+EAs1Ki+HOg21JzM= Message-ID: <1587566490.3485.7.camel@HansenPartnership.com> Subject: Re: [PATCH V2] scsi: put hot fields of scsi_host_template into one cacheline From: James Bottomley To: Ming Lei , linux-scsi@vger.kernel.org, "Martin K . Petersen" Cc: Bart Van Assche , Christoph Hellwig , John Garry Date: Wed, 22 Apr 2020 07:41:30 -0700 In-Reply-To: <20200422095425.319674-1-ming.lei@redhat.com> References: <20200422095425.319674-1-ming.lei@redhat.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.26.6 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org 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? James