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=-0.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,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 16452C3F2CE for ; Sun, 1 Mar 2020 09:03:09 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 B380A214DB for ; Sun, 1 Mar 2020 09:03:08 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="BYXdMZm9" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B380A214DB Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=joshtriplett.org 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=bombadil.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=PkLoINL8iRUkIvd60VotzcK3be5Iode/O+X7XYhjgas=; b=BYXdMZm9T0AD/O QdMujws4DXgps135LjHZpOQOjIIGFX2FQkGIXEDjyQ//Eazs21jr9qgQfDAETXZ1ct/b/Rl2ftd3S 8+5TaT5krAJrNVR8JbQYk1NuSFT9R1uTRMAV9sedHTPLuonKb7v0JRRFLbnU+pctnTFiaodc2Bq9W CqII6mXRl8+H2bZW7KQbPmddhVkHka5WFYv54ylUQmQcOPMYcI8O+/qa8roRxqUJCq1Ys8RstOeCL NUm269PaFXm+1ygtZBX/oGNjLP3ck7p9LeUr50GBeXdN+Qq5jXJZXdxG1vbUQQ9fQHtfPK1r9gVHr 68dROg1o6unIf6x0gaDw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1j8KV3-00045Z-KJ; Sun, 01 Mar 2020 09:03:01 +0000 Received: from relay7-d.mail.gandi.net ([217.70.183.200]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1j8KV0-00044x-72 for linux-nvme@lists.infradead.org; Sun, 01 Mar 2020 09:02:59 +0000 X-Originating-IP: 172.58.43.63 Received: from localhost (unknown [172.58.43.63]) (Authenticated sender: josh@joshtriplett.org) by relay7-d.mail.gandi.net (Postfix) with ESMTPSA id 9D74920006; Sun, 1 Mar 2020 09:02:43 +0000 (UTC) Date: Sun, 1 Mar 2020 01:02:39 -0800 From: Josh Triplett To: Chaitanya Kulkarni Subject: Re: [PATCH] nvme: Check for readiness more quickly, to speed up boot time Message-ID: <20200301090239.GC216567@localhost> References: <20200229025228.GA203607@localhost> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200301_010258_389950_DDFA1220 X-CRM114-Status: GOOD ( 13.00 ) 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: Sagi Grimberg , "linux-kernel@vger.kernel.org" , "linux-nvme@lists.infradead.org" , Jens Axboe , Keith Busch , Christoph Hellwig 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 Sun, Mar 01, 2020 at 02:01:05AM +0000, Chaitanya Kulkarni wrote: > Nit:- please have a look at the patch subject line and make > sure it is not exceeding the required length. Documentation/process/submitting-patches.rst says "no more than 70-75 characters,", and the summary here is 61. Checkpatch similarly says 75. Is there somewhere I missed that gives a different number? > One question though, have you seen similar kind of performance > improvements when system is booted ? I tested with nvme compiled in, both with one NVMe device and two NVMe devices, and in both cases it provided a *substantial* speedup. I didn't test nvme compiled as a module, but in general I'd expect that if you're trying to optimize initialization time you'd want to build it in. > I took some numbers and couldn't see similar benefit. See [1] :- > > Without :- > > 714.532560-714.456099 = .076461 > 721.189886-721.110845 = .079041 > 727.836938-727.765572 = .071366 > 734.589886-734.519779 = .070107 > 741.244296-741.173503 = .070793 With numbers in this range, I don't see how you could be hitting the 100ms msleep at all, even once, which means this patch shouldn't have any effect on the timing you're measuring. - Josh Triplett _______________________________________________ linux-nvme mailing list linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme 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=-0.8 required=3.0 tests=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 96B19C3F2CE for ; Sun, 1 Mar 2020 09:03:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 707AC214DB for ; Sun, 1 Mar 2020 09:03:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726146AbgCAJCt (ORCPT ); Sun, 1 Mar 2020 04:02:49 -0500 Received: from relay7-d.mail.gandi.net ([217.70.183.200]:52389 "EHLO relay7-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725747AbgCAJCt (ORCPT ); Sun, 1 Mar 2020 04:02:49 -0500 X-Originating-IP: 172.58.43.63 Received: from localhost (unknown [172.58.43.63]) (Authenticated sender: josh@joshtriplett.org) by relay7-d.mail.gandi.net (Postfix) with ESMTPSA id 9D74920006; Sun, 1 Mar 2020 09:02:43 +0000 (UTC) Date: Sun, 1 Mar 2020 01:02:39 -0800 From: Josh Triplett To: Chaitanya Kulkarni Cc: Keith Busch , Jens Axboe , Christoph Hellwig , Sagi Grimberg , "linux-kernel@vger.kernel.org" , "linux-nvme@lists.infradead.org" Subject: Re: [PATCH] nvme: Check for readiness more quickly, to speed up boot time Message-ID: <20200301090239.GC216567@localhost> References: <20200229025228.GA203607@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Mar 01, 2020 at 02:01:05AM +0000, Chaitanya Kulkarni wrote: > Nit:- please have a look at the patch subject line and make > sure it is not exceeding the required length. Documentation/process/submitting-patches.rst says "no more than 70-75 characters,", and the summary here is 61. Checkpatch similarly says 75. Is there somewhere I missed that gives a different number? > One question though, have you seen similar kind of performance > improvements when system is booted ? I tested with nvme compiled in, both with one NVMe device and two NVMe devices, and in both cases it provided a *substantial* speedup. I didn't test nvme compiled as a module, but in general I'd expect that if you're trying to optimize initialization time you'd want to build it in. > I took some numbers and couldn't see similar benefit. See [1] :- > > Without :- > > 714.532560-714.456099 = .076461 > 721.189886-721.110845 = .079041 > 727.836938-727.765572 = .071366 > 734.589886-734.519779 = .070107 > 741.244296-741.173503 = .070793 With numbers in this range, I don't see how you could be hitting the 100ms msleep at all, even once, which means this patch shouldn't have any effect on the timing you're measuring. - Josh Triplett