From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailout3.samsung.com (mailout3.samsung.com [203.254.224.33]) (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 29F2B1ACDFD for ; Fri, 17 Oct 2025 09:18:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=203.254.224.33 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760692703; cv=none; b=TcYgCi0kizPaeTv5vzHBQmM4bOBafapy78OsvtQv/ZttTn8j895dRQUqwYUZFxwG0yCWHl6oF5d3yPljADt+L20WYuJhaS0nyN0BYjPiEgI5MJBeMju6tEHeMrjJK91wh3NzgOVygBNSdbRI1wl3+lRlxXwBaVm4564TwFMAX1o= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760692703; c=relaxed/simple; bh=JkPVVdrPmlmTOUgJi1pFAq99L+0EF5ysO3v90EXy0WQ=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:MIME-Version: Content-Type:References; b=GBQEPkFzVAtGdRGTzwZE3obWYkIw+PFxFm+CQiFaNHUFGIaVt4zPz8lxBYXwbG5qfd1ayjeZcKPx4ZU4Yq3pbd/p1P/oHyavEpYyNYGRd5y2agtEXMSEjSx+kfXp9cy5n9/NbpceLBGdDElhR+sg79vwTV1NCMks1KZ70ibAVno= 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=fxsL9H51; arc=none smtp.client-ip=203.254.224.33 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="fxsL9H51" Received: from epcas5p3.samsung.com (unknown [182.195.41.41]) by mailout3.samsung.com (KnoxPortal) with ESMTP id 20251017091812epoutp033286157b430759e4f83bd0da63ad5194~vPKzKdBHY2549425494epoutp03d for ; Fri, 17 Oct 2025 09:18:12 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 mailout3.samsung.com 20251017091812epoutp033286157b430759e4f83bd0da63ad5194~vPKzKdBHY2549425494epoutp03d DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1760692692; bh=WLpos5VJo4ujXC7f9pS+oruhgvFGdqlCqiZ4Y8/B/4A=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=fxsL9H51OoGjzDDhEzccIStzUJfmjkiF9GULaDdG3uICkuJSC+D9EBneUSaBZZ8dV eX6N/NslvSb4LZ4cy+HtBtWnS4iPx3UYn+FQ+LV2TpKoyW/XkUc67XJygY32WMJKC4 0Qc/L0IfBL8q0lPkP2+S0WV3Xak50cWySFIx6gyY= Received: from epsnrtp03.localdomain (unknown [182.195.42.155]) by epcas5p4.samsung.com (KnoxPortal) with ESMTPS id 20251017091811epcas5p448adbd977948e060e0b4bab514410484~vPKy2TskK2886728867epcas5p4e; Fri, 17 Oct 2025 09:18:11 +0000 (GMT) Received: from epcas5p2.samsung.com (unknown [182.195.38.93]) by epsnrtp03.localdomain (Postfix) with ESMTP id 4cnzkg1NJcz3hhT4; Fri, 17 Oct 2025 09:18:03 +0000 (GMT) Received: from epsmtip1.samsung.com (unknown [182.195.34.30]) by epcas5p3.samsung.com (KnoxPortal) with ESMTPA id 20251017091046epcas5p35dfbcf4979f79b3a80441aed2d31a906~vPETq65qD0737307373epcas5p3y; Fri, 17 Oct 2025 09:10:46 +0000 (GMT) Received: from node122.. (unknown [109.105.118.122]) by epsmtip1.samsung.com (KnoxPortal) with ESMTPA id 20251017091045epsmtip18c89641ac9655ac1aec28f880b817f27~vPES5nsU-1493014930epsmtip1J; Fri, 17 Oct 2025 09:10:45 +0000 (GMT) From: Xiaobing Li To: changfengnan@bytedance.com Cc: asml.silence@gmail.com, axboe@kernel.dk, io-uring@vger.kernel.org, lidiangang@bytedance.com, kun.dou@samsung.com, peiwei.li@samsung.com, joshi.k@samsung.com Subject: Re: [PATCH] io_uring: add IORING_SETUP_NO_SQTHREAD_STATS flag to disable sqthread stats collection. Date: Fri, 17 Oct 2025 09:06:15 +0000 Message-Id: <20251017090615.6580-1-xiaobing.li@samsung.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: Precedence: bulk X-Mailing-List: io-uring@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CMS-MailID: 20251017091046epcas5p35dfbcf4979f79b3a80441aed2d31a906 X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-Sendblock-Type: REQ_APPROVE CMS-TYPE: 105P cpgsPolicy: CPGSC10-505,Y X-CFilter-Loop: Reflected X-CMS-RootMailID: 20251017091046epcas5p35dfbcf4979f79b3a80441aed2d31a906 References: On 10/16/25 20:09, Fengnan Chang wrote: >On 10/16/25 20:03, Pavel Begunkov wrote： >> >> On 10/16/25 12:45, Fengnan Chang wrote: >> > introduces a new flag IORING_SETUP_NO_SQTHREAD_STATS that allows >> > user to disable the collection of statistics in the sqthread. >> > When this flag is set, the getrusage() calls in the sqthread are >> > skipped, which can provide a small performance improvement in high >> > IOPS workloads. >> >> It was added for dynamically adjusting SQPOLL timeouts, at least that >> what the author said, but then there is only the fdinfo to access it, >> which is slow and unreliable, and no follow up to expose it in a >> better way. To be honest, I have serious doubts it has ever been used, >> and I'd be tempted to completely remove it out of the kernel. Fdinfo >> format wasn't really stable for io_uring and we can leave it printing >> some made up values like 100% util. > >Agree, IMO turning off stats by default would be a better approach, but >I'm concerned that some people are using this in fdinfo. I'd like to hear >the author's opinion. We use fdinfo statistics to evaluate some of our internal test data. Initially, I tested the performance impact of adding this feature, and the results showed that it had little impact on performance. Therefore, I didn't consider adding a switch to control its use. However, adding a switch to control whether to enable utilization statistics is a good idea. -- Xiaobing Li