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 X-Spam-Level: X-Spam-Status: No, score=-6.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 03814C433EF for ; Tue, 14 Sep 2021 05:59:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D3E98610FB for ; Tue, 14 Sep 2021 05:59:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239844AbhINGAc (ORCPT ); Tue, 14 Sep 2021 02:00:32 -0400 Received: from mailout1.samsung.com ([203.254.224.24]:11687 "EHLO mailout1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239359AbhINGAa (ORCPT ); Tue, 14 Sep 2021 02:00:30 -0400 Received: from epcas2p2.samsung.com (unknown [182.195.41.54]) by mailout1.samsung.com (KnoxPortal) with ESMTP id 20210914055911epoutp0123944890900f130c72a4775d7ffd47a2~kmsipPTYk1420014200epoutp01U for ; Tue, 14 Sep 2021 05:59:11 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 mailout1.samsung.com 20210914055911epoutp0123944890900f130c72a4775d7ffd47a2~kmsipPTYk1420014200epoutp01U DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=samsung.com; s=mail20170921; t=1631599151; bh=CqEjZQuCMDS2ROC6JzgcbDJfIGS65t1ChHRfPgvFvKc=; h=From:To:Subject:Date:References:From; b=Sf0XoCMvj68P1X4iAB63uipngeiJ1dUlSC/Mk0qDtGyQdtHWivy+6zn79r0++G7/y 62TgxObV+ajYyva6fD4LqfJVOaVHtu9Jw/34/zBFwqpUp0kbw3RcduEj/Z12ua2lYh Mj+yRsiQyel21Vp+LGsuEfCConwTctD0quHgW5DA= Received: from epsnrtp3.localdomain (unknown [182.195.42.164]) by epcas2p4.samsung.com (KnoxPortal) with ESMTP id 20210914055911epcas2p4f9b533a8d8e96b87be234f9b68aa0511~kmsiEDQg21315213152epcas2p4D; Tue, 14 Sep 2021 05:59:11 +0000 (GMT) Received: from epsmges2p3.samsung.com (unknown [182.195.40.191]) by epsnrtp3.localdomain (Postfix) with ESMTP id 4H7t2h6hkRz4x9QQ; Tue, 14 Sep 2021 05:59:08 +0000 (GMT) Received: from epcas2p3.samsung.com ( [182.195.41.55]) by epsmges2p3.samsung.com (Symantec Messaging Gateway) with SMTP id 0C.EC.09749.C2A30416; Tue, 14 Sep 2021 14:59:08 +0900 (KST) Received: from epsmtrp2.samsung.com (unknown [182.195.40.14]) by epcas2p1.samsung.com (KnoxPortal) with ESMTPA id 20210914055907epcas2p1c9d5d91c61592a67b9ce4b2a88d8f279~kmsebsi_E2282322823epcas2p1k; Tue, 14 Sep 2021 05:59:07 +0000 (GMT) Received: from epsmgms1p1new.samsung.com (unknown [182.195.42.41]) by epsmtrp2.samsung.com (KnoxPortal) with ESMTP id 20210914055907epsmtrp2a5d75cc40f149affcc2554268d5e420a~kmseax96f2427024270epsmtrp2N; Tue, 14 Sep 2021 05:59:07 +0000 (GMT) X-AuditID: b6c32a47-d29ff70000002615-c8-61403a2c96d4 Received: from epsmtip2.samsung.com ( [182.195.34.31]) by epsmgms1p1new.samsung.com (Symantec Messaging Gateway) with SMTP id 13.91.09091.A2A30416; Tue, 14 Sep 2021 14:59:06 +0900 (KST) Received: from KORCO011456 (unknown [12.36.185.54]) by epsmtip2.samsung.com (KnoxPortal) with ESMTPA id 20210914055906epsmtip2f4f257ce1dad645652694be6a76463f3~kmseKnXpt2534925349epsmtip2X; Tue, 14 Sep 2021 05:59:06 +0000 (GMT) From: "Kiwoong Kim" To: , , , , , , , , , , , , Subject: Question about ufs_bsg Date: Tue, 14 Sep 2021 14:59:06 +0900 Message-ID: <000001d7a92d$a0edcb00$e2c96100$@samsung.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Mailer: Microsoft Outlook 16.0 Thread-Index: AdepKfDft4+mL617SwWrELRDClUMdw== Content-Language: ko X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFjrCJsWRmVeSWpSXmKPExsWy7bCmua6OlUOiwYPlLBYnn6xhs3gwbxub xcufV9ksDj7sZLH4uvQZq8Wn9ctYLVYvfsBisejGNiaLy7vmsFl0X9/BZrH8+D8mi667Nxgt lv57y+LA63G5r5fJY/Gel0weExYdYPT4vr6DzePj01ssHn1bVjF6fN4k59F+oJspgCMqxyYj NTEltUghNS85PyUzL91WyTs43jne1MzAUNfQ0sJcSSEvMTfVVsnFJ0DXLTMH6GYlhbLEnFKg UEBicbGSvp1NUX5pSapCRn5xia1SakFKToGhYYFecWJucWleul5yfq6VoYGBkSlQZUJOxqce 4YIVnBUX3hxmaWBczd7FyMkhIWAicWvdbsYuRi4OIYEdjBIzJ5xlh3A+MUpMbDrMBOF8Y5R4 2XsKruXNwZksILaQwF5GiR8vbSCKXjBKHFyxmQkkwSagLTHt4W5WkISIwA0miU33t4MlhAXk JS6v2sAGYrMIqEpc+XcCLM4rYClxcM0zNghbUOLkzCdgG5iBBi1b+JoZYrOCxM+ny1hBbBEB PYmJD34yQtSISMzubIOqWcshMX2hHoTtInHy9hImCFtY4tXxLVAfSEl8freXDcKul9g3tQHs UAmBHkaJp/v+MUIkjCVmPWsHsjmAFmhKrN+lD2JKCChLHLkFdRqfRMfhv+wQYV6JjjYhiEZl iV+TJkMNkZSYefMO1FYPifXXjrJCwi1WYsOxXcwTGBVmIXl4FpKHZyF5bBbCDQsYWVYxiqUW FOempxYbFRgjx/UmRnBy1nLfwTjj7Qe9Q4xMHIyHGCU4mJVEeLe9sU0U4k1JrKxKLcqPLyrN SS0+xGgKjIKJzFKiyfnA/JBXEm9oamRmZmBpamFqZmShJM57/rVlopBAemJJanZqakFqEUwf EwenVAMTs87lwN8Pm7e9etQvdu19z798O5/gQ09mbmRnaVhjobOCo/fhknWqc/1ZN07oPnzg k9VzqQ1n5ixPe6SWXBldtTp4ae7KwobbB1y2CK7ffCPyuqjDpmfLuP6xHXvafb4sSb3/v6NK YkXuBtnP3J+tPrTu4/ZUfWka61iQENIdl7RKYHNeu1GuQ/a/++WJu7KkohZtUnUQ3eP35nYD a9Xz7Se2Ky4/O2Nm3fZrr1NlXDxc+RuEDPSaJnnsyvbsnqddf87wzMr1Sr82ruX49XN5mbn6 C++eVbzn+7gFf2dG/OTPsjkxSb9w/iqVLs9oR4EbXHrLjm3+e4N9eeJhUY7qyl9r7RiO3te8 pHP5W1CvEktxRqKhFnNRcSIAWApvaFcEAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFuplkeLIzCtJLcpLzFFi42LZdlhJXlfLyiHRYPdaG4uTT9awWTyYt43N 4uXPq2wWBx92slh8XfqM1eLT+mWsFqsXP2CxWHRjG5PF5V1z2Cy6r+9gs1h+/B+TRdfdG4wW S/+9ZXHg9bjc18vksXjPSyaPCYsOMHp8X9/B5vHx6S0Wj74tqxg9Pm+S82g/0M0UwBHFZZOS mpNZllqkb5fAldG2dTtTwQrOir0nvjI3MK5m72Lk5JAQMJF4c3AmSxcjF4eQwG5Gif4Fx5gg EpISJ3Y+Z4SwhSXutxxhhSh6xiixdPcBsG42AW2JaQ93gyVEBF4wSfzbv5kNJCEsIC9xedUG MJtFQFXiyr8TYFN5BSwlDq55xgZhC0qcnPmEBcRmBhr09OZTOHvZwtfMEJsVJH4+XcYKYosI 6ElMfPCTEaJGRGJ2ZxvzBEaBWUhGzUIyahaSUbOQtCxgZFnFKJlaUJybnltsWGCYl1quV5yY W1yal66XnJ+7iREcY1qaOxi3r/qgd4iRiYPxEKMEB7OSCO+2N7aJQrwpiZVVqUX58UWlOanF hxilOViUxHkvdJ2MFxJITyxJzU5NLUgtgskycXBKNTBl2Jw99KyH3+vDC3amkqteL3acbL41 v+v5r7ddc7UOrlmSsj4x0j5S1VLb0NziuE6W51Oz4wlVp1f/bfErvviq8l7KHNW5aZyHvCff qnZc0ZxnLbtk8Zb7abdOWPD/bTsiwX7sieWCFLnNX783NRSrbuypXLrE6KPJkr0i5ZeKXqpc mV54PfVm0pFzJ+wzfr6L+3mrYv23idc0TkxiVb47ZbtYcI/ARuF/h+ozXC26Nvz9FxC7Z820 z/EBvrERbWzxOyYHBbNpXfxhznM5JfO9UPxZy+une8J3266bynrMvSpqVtzhtSECGdEzZifk eomGVd1c0st4lGGhquCZjvrUU6s0cm6mTm1a+vrAgWc/lFiKMxINtZiLihMBDEm58yADAAA= X-CMS-MailID: 20210914055907epcas2p1c9d5d91c61592a67b9ce4b2a88d8f279 X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-Sendblock-Type: AUTO_CONFIDENTIAL CMS-TYPE: 102P DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20210914055907epcas2p1c9d5d91c61592a67b9ce4b2a88d8f279 References: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, ufs_bsg was introduced nearly three years ago and it allocates its own requ= est queue. I faced a sytmpom with this and want to ask something about it. That is, sometimes queue depth for ufs is limited to half of the its maximu= m value even in a situation with many IO requests from filesystem. It turned out that it only occurs when a query is being processed at the sa= me time. Regarding my tracing, when the query process starts, users for the hctx tha= t represents a ufs host increase to two and with this, some pathes calling 'hctx_may_que= ue' function in blk-mq seems to throttle dispatches, technically with 16 becaus= e the number of ufs slots (32 in my case) is dividend by two (users). I found that it happened when a query for write booster is processed because write booster only turns on in some conditions in my base that is d= ifferent from kernel mainline. But when an exceptional event or others that could le= ad to a query occurs, it can happen even in mainline. I think the throttling is a little bit excessive, so the question: is there any way to assign queue depth per user on an asym= metric basis? Thanks. Kiwoong Kim