From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=91.218.175.152 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792500552; b=vi2kgBmlE8nGj0RMP0YZH3Mb6hxOSdavobJW7JywXcfo2ZCHGQAA4wq9qGGVSJ/unIJg Zz0UJE6Xos4ZoGkXiUKoDeG16SQ/iqAR+aKnhyywEEtnAar5rcIofJkKjRtF/b7beTEc1 cn+mNP/fjT09ZRNC1IFJoxzxw8PCRxRDXkNi+si3mPGB/etE8YK3XVvdMSjiXI4h30Z7r e7nJqTF4J2x2UzZ7mZYJApFFHI5zSDw+WqZ4rp/9hYz6Py41NqnJnMdy6oqxWOzJ5PcVv sptxSUN+Zh6ZtHrPH1giUqHT/7Ooa48Plx7gRHGUdV7iCO9IaHpZeqAicu1gsFvlaTA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792500552; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:Message-ID:Date:MIME-Version:User-Agent: Subject:To:Cc:References:From:In-Reply-To:Content-Type: Content-Transfer-Encoding; bh=FAeVOIir4HMk1KRsfGRYBGjRZCtdGNjoG1cMCUcwWcQ=; b=qU/FxzLlFrXjAtS/s4xxKdQ0u4baNKoMoB6DrV3VHmd63YU8I3ExiO05WT8MEb+Xxkek vT+wvdPMvhR7A+fwDoCzbL8oikHIaP9su8npZed/9dRlbWj7PG4e8cAF3l2dCbdlYaQW8 2Ht55pOtBptF0/tBuRFtR1hfXvuBPtrJt468iwahnTgdqKNQwxYwPVAuRwMbRkqBMr+6n hi9gBzotBeB6SAxctDbY0GdPznhVx5uv0RSfS3hapmoSL2sJV0yQO7yQfaD1s6JUcHum6 oMqAQxG5lHt93Pe7O9XEU9RhmUVEp7uB9y0YTc9pnYFeqEMHzMyb1Vgnbm7bjBZPvFw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=oEUtcdpc; arc=none smtp.remote-ip=91.218.175.152 Received: from mta0.migadu.com (out-152.mta0.migadu.com [91.218.175.152]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D2EC8606A319 for ; Tue, 20 Oct 2026 12:49:10 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org D2EC8606A319 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=oEUtcdpc X-Envelope-To: linux-block@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=O0ZvGw0ZoKFzAZ1EP4MQE4G7MB6j6Lu1fMegrKdHYqw=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1792500548; v=1; x=1793105348; b=oEUtcdpcdk9esWoFxS2HUgXoj2xbr27DC60xMLZGGZFmXPL8YiZwHM+B/yNmyAzarE3ARB4O LzSToGH7VZtEp6FaCsEQ9+fbs+RBfgxqSrWKj1812CrIfpBFHXk+yT0+jHlHyyhVzsXqrUedkbV 2tLqIadHyowX1RgLxDTzByCM= X-Envelope-To: linux-block@vger.kernel.org Received: by mta10.migadu.com with ESMTPS id 765e9563e2983e52; Tue, 20 Oct 2026 12:49:08 +0000 X-Mizu-Trace-ID: 765e9563e2983e52 X-Migadu-Flow: FLOW_OUT Message-ID: <95c88c33-0184-4258-ac02-8eb42f346b36@linux.dev> Date: Tue, 20 Oct 2026 20:49:03 +0800 X-Mailing-List: linux-block@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] blk-mq: add direct dispatch support for mq-deadline To: Bart Van Assche , Jens Axboe , Jonathan Corbet , Shuah Khan , Randy Dunlap Cc: linux-block@vger.kernel.org, Kaitao Cheng References: <20261017105400.95967-1-kaitao.cheng@linux.dev> <307b05d7-16dd-493a-a10a-d5ac50ec219b@acm.org> From: Kaitao Cheng In-Reply-To: <307b05d7-16dd-493a-a10a-d5ac50ec219b@acm.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 在 2026/10/17 22:19, Bart Van Assche 写道: > On 10/17/26 3:54 AM, Kaitao Cheng wrote: >> Bandwidth in MiB/s: >> >>    Workload        none    mq-deadline    my-patch >>    jobs1-4k        1209           1047        1174 >>    jobs10-4k       2458            946        2349 >>    jobs1-32k       2568           2565        2562 > > Can I conclude from the above numbers that "none" performs > better than "mq-deadline" and hence that it's better not to use > and I/O scheduler rather than to complicate the mq-deadline source > code? > > I have removed the linux-doc and linux-kernel mailing lists from the > Cc-list. Block layer patches should be posted on the linux-block mailing > list only. > I ran additional tests on both a SATA SSD and a SAS HDD. The results are as follows: SATA SSD none mq-deadline my-patch jobs1-4k 294 295 295 jobs10-4k 133 400 401 jobs1-32k 470 470 470 SAS HDD none mq-deadline my-patch jobs1-4k 218 218 218 jobs10-4k 26.6 26.9 27.2 jobs1-32k 225 224 224 The SAS HDD results show no clear performance differences. On the SATA SSD, however, mq-deadline outperforms none, and my patch preserves mq-deadline's performance. Together with the earlier NVMe SSD results, these results suggest that the patch combines the benefits of both none and mq-deadline. I also found in the NVMe SSD tests that disabling the direct dispatch paths used with the none scheduler causes its performance to drop to the same level as mq-deadline. -- Thanks Kaitao Cheng