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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6FF80C4708D for ; Thu, 8 Dec 2022 00:36:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229714AbiLHAgI (ORCPT ); Wed, 7 Dec 2022 19:36:08 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52636 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229462AbiLHAgG (ORCPT ); Wed, 7 Dec 2022 19:36:06 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0075224BF6; Wed, 7 Dec 2022 16:36:05 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id AA578B8219F; Thu, 8 Dec 2022 00:36:04 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 43AF6C433C1; Thu, 8 Dec 2022 00:35:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1670459763; bh=8EqImzFDFK7SCDTb85EZXzmxEthwAPbCP4u3wA+fVVk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Qj8Ws3/FmYV9fzKhoMQtZHpgfiJPp8CSx2k3z/uJYemAhWfiuguoZUtJhnQHpjxTN kAOwhDMb+3g2v60wt+E/ozBrWcN+iAy1T7zW4jScRe1kZMeAY51aT3uLWqyTEkLCIg wObJgbcpW/t56PgtA6J40EnoAILsAVmP7mtN5dzBthLb32oQ2MoczwQgGWI2PHzxMc XfgcYqvOB6UfnujKHBnXLFPww/KeIdmPdPuRzD7XPsKoRg5Az8bfQVGpEDdkDFadoC m/2roapq2yF9V3+XdCIyDjtcP348AvcPbX+5jc8CCN9CbJ7HEmWCEySFVIoXuiAH2L ee3NvjHxGvObw== Date: Thu, 8 Dec 2022 00:35:55 +0000 From: Keith Busch To: Chaitanya Kulkarni Cc: Jens Axboe , Gulam Mohamed , "linux-block@vger.kernel.org" , "philipp.reisner@linbit.com" , "lars.ellenberg@linbit.com" , "christoph.boehmwalder@linbit.com" , "minchan@kernel.org" , "ngupta@vflare.org" , "senozhatsky@chromium.org" , "colyli@suse.de" , "kent.overstreet@gmail.com" , "agk@redhat.com" , "snitzer@kernel.org" , "dm-devel@redhat.com" , "song@kernel.org" , "dan.j.williams@intel.com" , "vishal.l.verma@intel.com" , "dave.jiang@intel.com" , "ira.weiny@intel.com" , "junxiao.bi@oracle.com" , "martin.petersen@oracle.com" , "drbd-dev@lists.linbit.com" , "linux-kernel@vger.kernel.org" , "linux-bcache@vger.kernel.org" , "linux-raid@vger.kernel.org" , "nvdimm@lists.linux.dev" , "konrad.wilk@oracle.com" , "joe.jin@oracle.com" Subject: Re: [RFC for-6.2/block V2] block: Change the granularity of io ticks from ms to ns Message-ID: References: <20221207223204.22459-1-gulam.mohamed@oracle.com> <09be5cbe-9251-d28c-e91a-3f2e5e9e99f2@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <09be5cbe-9251-d28c-e91a-3f2e5e9e99f2@nvidia.com> Precedence: bulk List-ID: X-Mailing-List: linux-raid@vger.kernel.org On Wed, Dec 07, 2022 at 11:17:12PM +0000, Chaitanya Kulkarni wrote: > On 12/7/22 15:08, Jens Axboe wrote: > > > > My default peak testing runs at 122M IOPS. That's also the peak IOPS of > > the devices combined, and with iostats disabled. If I enabled iostats, > > then the performance drops to 112M IOPS. It's no longer device limited, > > that's a drop of about 8.2%. > > > > Wow, clearly not acceptable that's exactly I asked for perf > numbers :). For the record, we did say per-io ktime_get() has a measurable performance harm and should be aggregated. https://www.spinics.net/lists/linux-block/msg89937.html