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=-5.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 6CF26C433E9 for ; Thu, 3 Sep 2020 16:18:12 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3ADD120775 for ; Thu, 3 Sep 2020 16:18:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="oFH1slSE" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3ADD120775 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=tnSwpCrzsJyH3jCF9I/e/PoO2a3R6I1o5kue4f0NNWo=; b=oFH1slSEpNH3bkyGeUhoLmpPU TYxNRxM15qrqjCWcmnJR5Ril02zEdrIiOfH+AQDwGax13135oxsTLzM23Ewy+7Pb7j407wLjrVZsg uNlNB94G6iNU7dcS96Thua/VkosAphuFnzLpbdnJhJTptlfYiqd86rPAyt5EwHagOQ/G2qfLe+uEk YvhtGa8sxYyct0HG6pL6lfHc53jCveRSyH7C5RpqgYB3PlhfOgIHWiVMCKsYlYloN9CUWcW3hGvVS tpZKG+Ph3T9vRdwvt5Jfm9BXSwk5CEDFecluhTpd4y7xhcRbw/4OztrclXE1x0J/AGKes5NOphyfU Mt6n39Hvg==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kDrwA-00068J-6y; Thu, 03 Sep 2020 16:18:10 +0000 Received: from verein.lst.de ([213.95.11.211]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kDrw7-00067g-BR for linux-nvme@lists.infradead.org; Thu, 03 Sep 2020 16:18:07 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id BA58E67357; Thu, 3 Sep 2020 18:18:05 +0200 (CEST) Date: Thu, 3 Sep 2020 18:18:05 +0200 From: Christoph Hellwig To: Chaitanya Kulkarni Subject: Re: [PATCH V2 02/12] nvmet: for pt I/O commands use likely for ns check Message-ID: <20200903161805.GB25423@lst.de> References: <20200831222707.35611-1-chaitanya.kulkarni@wdc.com> <20200831222707.35611-3-chaitanya.kulkarni@wdc.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200831222707.35611-3-chaitanya.kulkarni@wdc.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200903_121807_496136_43992203 X-CRM114-Status: GOOD ( 10.36 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kbusch@kernel.org, logang@deltatee.com, hch@lst.de, linux-nvme@lists.infradead.org, sagi@grimberg.me Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Mon, Aug 31, 2020 at 03:26:57PM -0700, Chaitanya Kulkarni wrote: > I/O commands (nvme_cmd_read, nvme_cmd_write) are most common commands > when accessing passthru controller. Since for I/O commands ns is always > present and the condition is marked as likely. Annotate post request > submission ns check with likely which is dependent on earlier the ns > check likely condition. This really seems like weird over-optimization. Any sensible branch predictor should be able to find this out by itself. _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme