From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailout4.samsung.com (mailout4.samsung.com [203.254.224.34]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 959EF1F03DE for ; Wed, 29 Jul 2026 08:35:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=203.254.224.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785314115; cv=none; b=QHXmx5xAU2qkqE9VKhpeQh4hJCZXkCbFnpu40WWYsIeuuHQ/Bzuvdc+nF19Mfb1bZklZW54sBliuP8UDaVEyr/ToM62tOF6aB4gwF5ovXHwgF2PD3biVdQoDG9Quov98LIMcS4k43ObK6Mu2mUFje1aENW5GB/QHJi3OHBUQjvE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785314115; c=relaxed/simple; bh=/lbc0ds/nEhSKq+pRS0v21OIZIp8lfmi/G5Th/cuNpI=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:MIME-Version: Content-Type:References; b=ARpKtvQ2HcFZiuiBb4b6T2Bgu7tAiPSeNx0eDNNFRxFzNK22cNwiFSTsWp+uyIbWG2H8j3HHOv4kuLz53f/ao9VtOq0fdJzFk3ZEC/0kZFOprh5pzYVuQd8bqqumyUJCDOQSpxlzBDkxieQeW6Wu6tBDsbp5s580BGWmeUtTZAw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=samsung.com; spf=pass smtp.mailfrom=samsung.com; dkim=pass (1024-bit key) header.d=samsung.com header.i=@samsung.com header.b=saiJoAhy; arc=none smtp.client-ip=203.254.224.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=samsung.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=samsung.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=samsung.com header.i=@samsung.com header.b="saiJoAhy" Received: from epcas5p4.samsung.com (unknown [182.195.41.42]) by mailout4.samsung.com (KnoxPortal) with ESMTP id 20260729083503epoutp0466a9ed60278145e493c377a2f6a1c71c~GtbfVr2uI0385403854epoutp04d for ; Wed, 29 Jul 2026 08:35:03 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 mailout4.samsung.com 20260729083503epoutp0466a9ed60278145e493c377a2f6a1c71c~GtbfVr2uI0385403854epoutp04d DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1785314103; bh=nMumBf6pcwJN35QNg21EPnkz/AZt8LVlK2YGNnvhzR0=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=saiJoAhy/r7KRwVHHR7YIjl+Nj7jXx0336/L9WpCTejiCSFqRiZqSbxMvaUbv8NU+ kkSUaNQ8zh8zuU9bBheB7sAGTwYiYPlFaARqwxR9n2aNYqgqXqjBwiJx3DUq/t9TEv QBtUstpUNwLJo7RQ4CaoQbXAPVsNOYFEScxUaHCY= Received: from epsnrtp01.localdomain (unknown [182.195.42.153]) by epcas5p2.samsung.com (KnoxPortal) with ESMTPS id 20260729083502epcas5p2956791f6317ffa4deaefdfb2eaa3c15c~Gtbeng5sa2833528335epcas5p2F; Wed, 29 Jul 2026 08:35:02 +0000 (GMT) Received: from epcpadp1new (unknown [182.195.40.141]) by epsnrtp01.localdomain (Postfix) with ESMTP id 4h95HV4cXxz6B9m7; Wed, 29 Jul 2026 08:35:02 +0000 (GMT) Received: from epsmtip1.samsung.com (unknown [182.195.34.30]) by epcas5p4.samsung.com (KnoxPortal) with ESMTPA id 20260728145333epcas5p427c6b6d72bff02de3f29e6a6a2108958~Ge8rj7-9K0791907919epcas5p40; Tue, 28 Jul 2026 14:53:33 +0000 (GMT) Received: from green245.samsungds.net (unknown [107.99.41.245]) by epsmtip1.samsung.com (KnoxPortal) with ESMTPA id 20260728145330epsmtip1f20094ebf53bcd1bb08fe2dba866c798~Ge8oxGFnu0743207432epsmtip1b; Tue, 28 Jul 2026 14:53:30 +0000 (GMT) From: Alok Rathore To: wangyang.guo@intel.com Cc: akpm@linux-foundation.org, axboe@fb.com, dan.liang@intel.com, hch@lst.de, kbusch@kernel.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, ming.lei@redhat.com, rrendec@redhat.com, sagi@grimberg.me, tglx@linutronix.de, tianyou.li@intel.com, tim.c.chen@linux.intel.com, virtualization@lists.linux-foundation.org, asml.silence@gmail.com, cpgs@samsung.com, gost.dev@samsung.com, alokrathore20@gmail.com, nitheshshetty@gmail.com, Alok Rathore Subject: Re: [PATCH v2] lib/group_cpus: make group CPU cluster aware Date: Tue, 28 Jul 2026 20:23:03 +0530 Message-Id: <561480862.11785314102640.JavaMail.epsvc@epcpadp1new> X-Mailer: git-send-email 2.39.5 In-Reply-To: <20260113022958.3379650-1-wangyang.guo@intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CMS-MailID: 20260728145333epcas5p427c6b6d72bff02de3f29e6a6a2108958 X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" CMS-TYPE: 105P X-CPGSPASS: Y X-Hop-Count: 3 X-CMS-RootMailID: 20260728145333epcas5p427c6b6d72bff02de3f29e6a6a2108958 References: <20260113022958.3379650-1-wangyang.guo@intel.com> For higher number of jobs(>=64), we are seeing ~8% regression with this patch. Tool: fio with io_uring engine [1] +------------+------------+-------------------+ | numjobs | before | after patch | +------------+------------+-------------------+ | 1 | 89 | 88.8 (-0.22%) | | 2 | 169 | 168 (-0.59%) | | 4 | 338 | 337 (-0.30%) | | 8 | 533 | 533 (0.00%) | | 16 | 538 | 541 (+0.56%) | | 32 | 685 | 716 (+4.53%) | | 64 | 933 | 859 (-7.93%) | | 128 | 941 | 867 (-7.86%) | +------------+------------+-------------------+ * Metric: IOPS (K) (Block device, QD = 1, bs = 4K, Random Read) As shown in the table above, while performance is comparable at low job counts, there is a drop starting from 64 jobs after this patch. HW info: Intel(R) Core(TM) Ultra 7 265K CPU=20 IRQ-CPU are 1:1 mapped. [1] fio -filename=/dev/nvme0n1 -direct=1 -size=4g -rw=randread \ -numjobs=$(numjobs) -bs=4096 -ioengine=io_uring -iodepth=1 \ -name=uring_test --registerfiles=1 --ramp_time=5 \ --group_reporting --thread