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=-5.8 required=3.0 tests=BAYES_00,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 82EC3C433B4 for ; Tue, 18 May 2021 17:55:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5B1EC61209 for ; Tue, 18 May 2021 17:55:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345036AbhERR5N (ORCPT ); Tue, 18 May 2021 13:57:13 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46000 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245549AbhERR5N (ORCPT ); Tue, 18 May 2021 13:57:13 -0400 Received: from bedivere.hansenpartnership.com (bedivere.hansenpartnership.com [IPv6:2607:fcd0:100:8a00::2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 370C5C061573 for ; Tue, 18 May 2021 10:55:55 -0700 (PDT) Received: from localhost (localhost [127.0.0.1]) by bedivere.hansenpartnership.com (Postfix) with ESMTP id D6074128085A; Tue, 18 May 2021 10:55:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=hansenpartnership.com; s=20151216; t=1621360554; bh=apDhDtlHY7d2Uz2L6bA1Ig1mqsN1sJl/KfLF7DIb9tI=; h=Message-ID:Subject:From:To:Date:In-Reply-To:References:From; b=ks0+HZvNETSJhoHdkwPhS5VK/DmUhVA8oHxHCq21DyvnUESUvweA7ti9Bq9l8m5Zm grrRPo+zIWsscJLqITZxmx0PAAvuGavpu6Gu7YhclsSWGz9L1p29dZhe6sYo6JMziQ 9tBNe1uepKXSqhYpDSuDqHO6VDyZsT03bcCOUNGw= 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 pr1hpSwTn-Ld; Tue, 18 May 2021 10:55:54 -0700 (PDT) Received: from jarvis.int.hansenpartnership.com (unknown [IPv6:2601:600:8280:66d1::527]) (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 7E2C312807CC; Tue, 18 May 2021 10:55:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=hansenpartnership.com; s=20151216; t=1621360554; bh=apDhDtlHY7d2Uz2L6bA1Ig1mqsN1sJl/KfLF7DIb9tI=; h=Message-ID:Subject:From:To:Date:In-Reply-To:References:From; b=ks0+HZvNETSJhoHdkwPhS5VK/DmUhVA8oHxHCq21DyvnUESUvweA7ti9Bq9l8m5Zm grrRPo+zIWsscJLqITZxmx0PAAvuGavpu6Gu7YhclsSWGz9L1p29dZhe6sYo6JMziQ 9tBNe1uepKXSqhYpDSuDqHO6VDyZsT03bcCOUNGw= Message-ID: Subject: Re: [PATCH v2 00/50] Remove the request pointer from struct scsi_cmnd From: James Bottomley To: Bart Van Assche , "Martin K . Petersen" Cc: linux-scsi@vger.kernel.org Date: Tue, 18 May 2021 10:55:53 -0700 In-Reply-To: <20210518174450.20664-1-bvanassche@acm.org> References: <20210518174450.20664-1-bvanassche@acm.org> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.34.4 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org On Tue, 2021-05-18 at 10:44 -0700, Bart Van Assche wrote: > Hi Martin, > > This patch series implements the following two changes for all SCSI > drivers: > - Use blk_mq_rq_from_pdu() instead of the request member of struct > scsi_cmnd > since adding an offset to a pointer is faster than pointer > indirection. Are there any performance results to back up this assertion? It's quite a lot of churn so it would be nice to know it's worth it. James