From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-io1-f41.google.com (mail-io1-f41.google.com [209.85.166.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1E4902E820 for ; Thu, 18 Jan 2024 20:22:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.41 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705609369; cv=none; b=ETs4S8Gu9OtwbPDeOBrQ6ky47JGqROzHV/ON1bC9PmVlzYGwY4FXOMTdVjvc41ObRTXoxNkawsziUzD/r0Ca8MElsg6vfbd/p4mdxAKPzvQlALOMyao9DuQ+gENfAYHbyFmU0icWdnnga7Lf+PFYFOcV3qsBabZ0HRP7G3BGRtw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1705609369; c=relaxed/simple; bh=0/yo8LHYQFq33spx9yfzd8+mCK8PI2lhE2GFZc9eIQU=; h=Message-ID:Date:MIME-Version:Subject:From:To:Cc:References: In-Reply-To:Content-Type; b=TlkysVfhs/tAjkB+sqzDJExNecavb0z9/If/NsoFHVdn+arw3a00/ueM9+dr6sgC1j6f1Fu8hr29fNBXcnfC0CuA2fOWNqgrhNmm6boktewOnYrvxY98JQqDhZQOoTuwUmUHp6bVjfokD/lm+NAGs+fWm2QtleawdqZVScnImV8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk; spf=pass smtp.mailfrom=kernel.dk; dkim=pass (2048-bit key) header.d=kernel-dk.20230601.gappssmtp.com header.i=@kernel-dk.20230601.gappssmtp.com header.b=HehDMZNL; arc=none smtp.client-ip=209.85.166.41 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.dk Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=kernel.dk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20230601.gappssmtp.com header.i=@kernel-dk.20230601.gappssmtp.com header.b="HehDMZNL" Received: by mail-io1-f41.google.com with SMTP id ca18e2360f4ac-7bee01886baso715639f.1 for ; Thu, 18 Jan 2024 12:22:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20230601.gappssmtp.com; s=20230601; t=1705609365; x=1706214165; darn=vger.kernel.org; h=content-transfer-encoding:in-reply-to:references:cc:to:from :content-language:subject:user-agent:mime-version:date:message-id :from:to:cc:subject:date:message-id:reply-to; bh=ESGKayx9JW+ADD0aYy93pZDrn8Ax/uELnUncqR3mJM4=; b=HehDMZNLZ5EODg7dzeAo/B9x5Iy7+8tD8VJcb5IRaezPj1HZYr7YdYITZBSKa6MGwk aIV9CBqihjoOG6mYhmDCqfIYKG0Dq5iHjqlolrVZoBtuqccc231T2GMBVZJIHzTQtTpt FnuC9KmstcjnZRIcmnYGl21Yi0WcHwEuUGCulkzJzKKrj3hiq6OYFNosbC7BQDPbpy/i ghvue0hfG7dFJ/gSb1EPOUpXeRyQwPzIzjCdUZwdvS47AOU1h0KtsRogheYIJ2YcCZzw GcGmZXS7BevZMciHncClsmNJiQW1Ad0BdybjhfnO7JfBrtzz1NbIMIr/TBM0XjjDMeif SSEA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1705609365; x=1706214165; h=content-transfer-encoding:in-reply-to:references:cc:to:from :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=ESGKayx9JW+ADD0aYy93pZDrn8Ax/uELnUncqR3mJM4=; b=kTsW9fsnfLEK2DvL12HRW9KacQKnCTE5Z3ou8APHXqilUVmDRawsF7csNN1mzhgHUA 0LpowzF9TP9yLxK9UxexpndxZaoKG5gU1Wi87QnSEdy00BqYR7yN4dhNYyIT7gKNEcXS UyLfi4czGFowKwqIV4TpVP01NW3fwiDDjYwfF63UTZjGVSWkIU1TtDdyQVt+W+9cpGJb ntMXkolnSYpzXiJaAYGGyAlGSh3h4Ho/FKf6OnnZ7xXXeqqx+/auBtL0YCYmlr3i6emA ekdsgcgi2FGD06Foe8N2UYY3vF0PTHuwsUVZNSLBTfq/t5LF6Vw/0kArYDifZhH8fhqr syyg== X-Gm-Message-State: AOJu0YwGUtAo+jrEts8xuWFEv0Y8vkINkN2Wf2hLHQ62+rriTasNiUSS xzQ0CMguBaP0SFXTlO4wNcoN60Bq3k+hGTiYc0Utdful8NkTa++TNcJpKoRJB3Z8V83Hg8Jxp4B XJGk= X-Google-Smtp-Source: AGHT+IGXpPfApBll7Lcu26TL1fnY1W56ICZ1N7GYfggmRgp8kAZBi7JgNGwHWqSarPrDZHzjeTSXGw== X-Received: by 2002:a5e:8302:0:b0:7be:e376:fc44 with SMTP id x2-20020a5e8302000000b007bee376fc44mr513956iom.2.1705609365368; Thu, 18 Jan 2024 12:22:45 -0800 (PST) Received: from [192.168.1.116] ([96.43.243.2]) by smtp.gmail.com with ESMTPSA id x7-20020a056602160700b007bf0e4b4c63sm4263224iow.31.2024.01.18.12.22.44 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 18 Jan 2024 12:22:44 -0800 (PST) Message-ID: <7f1f90e9-d034-48da-8149-73a6dec20c9e@kernel.dk> Date: Thu, 18 Jan 2024 13:22:44 -0700 Precedence: bulk X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCHSET RFC 0/2] mq-deadline scalability improvements Content-Language: en-US From: Jens Axboe To: linux-block@vger.kernel.org Cc: bvanassche@acm.org References: <20240118180541.930783-1-axboe@kernel.dk> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 1/18/24 12:29 PM, Jens Axboe wrote: > On 1/18/24 11:04 AM, Jens Axboe wrote: >> With that in place, the same test case now does: >> >> Device QD Jobs IOPS Contention Diff >> ============================================================= >> null_blk 4 32 2250K 28% +106% >> nvme0n1 4 32 2560K 23% +112% > > nvme0n1 4 32 2560K 23% +139% > > Apparently I can't math, this is a +139% improvement for the nvme > case... Just wanted to make it clear that the IOPS number was correct, > it's just the diff math that was wrong. And further followup, since I ran some quick testing on another box that has a raid1 more normal drive (SATA, 32 tags). Both pre and post the patches, the performance is roughly the same. The bigger difference is that the pre result is using 8% systime to do ~73K, and with the patches we're using 1% systime to do the same work. This should help answer the question "does this matter at all?". The answer is definitely yes. It's not just about scalability, as is usually the case with improving things like this, it's about efficiency as well. 8x the sys time is ridiculous. -- Jens Axboe