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=-2.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_PASS,T_DKIMWL_WL_HIGH,URIBL_BLOCKED, USER_AGENT_MUTT autolearn=ham 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 08DF5C46460 for ; Wed, 15 Aug 2018 02:15:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9716E216E4 for ; Wed, 15 Aug 2018 02:15:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="gQ1vjCmB" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9716E216E4 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728466AbeHOFF2 (ORCPT ); Wed, 15 Aug 2018 01:05:28 -0400 Received: from mail.kernel.org ([198.145.29.99]:57192 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725946AbeHOFF1 (ORCPT ); Wed, 15 Aug 2018 01:05:27 -0400 Received: from localhost (unknown [104.132.1.88]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 9D907216E3; Wed, 15 Aug 2018 02:15:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1534299325; bh=fERiTZNfGAytv8X4Vc836s30KMWDkddgTy8atz3rJNE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=gQ1vjCmBWc33R0AYR8soXu7vHyl/EpkyV3qNohQPQ56dYOZjDidnWbUYQAgHcaF3W wqee5vwuwFcfZjOruD05i16pwcAkYDbF65iB7m1NLhJOMCCJ/M7fl+jO/oXmu1S6qH xjptfC1B1Yo6tcXxMzCS74NRcAEEtHnFDlqNvEwc= Date: Tue, 14 Aug 2018 19:15:24 -0700 From: Jaegeuk Kim To: Chao Yu Cc: linux-kernel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net Subject: Re: [f2fs-dev] [PATCH v3] f2fs: fix performance issue observed with multi-thread sequential read Message-ID: <20180815021524.GA84720@jaegeuk-macbookpro.roam.corp.google.com> References: <20180810023758.46974-1-jaegeuk@kernel.org> <20180810024859.GA48219@jaegeuk-macbookpro.roam.corp.google.com> <20180810185640.GA63079@jaegeuk-macbookpro.roam.corp.google.com> <57149b77-3576-87ed-2cae-a3bc2e8088f2@huawei.com> <20180813201150.GA27044@jaegeuk-macbookpro.roam.corp.google.com> <0e07e79b-5b67-9355-1fa0-402a5d118bd1@huawei.com> <20180814040434.GA52730@jaegeuk-macbookpro.roam.corp.google.com> <7194f3d2-b875-376a-4c46-37c598bf3e8e@huawei.com> <20180814172837.GD56510@jaegeuk-macbookpro.roam.corp.google.com> <167ce8f1-ee4d-2ffc-3518-32850465cd0c@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <167ce8f1-ee4d-2ffc-3518-32850465cd0c@huawei.com> User-Agent: Mutt/1.8.2 (2017-04-18) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/15, Chao Yu wrote: > On 2018/8/15 1:28, Jaegeuk Kim wrote: > > On 08/14, Chao Yu wrote: > >> On 2018/8/14 12:04, Jaegeuk Kim wrote: > >>> On 08/14, Chao Yu wrote: > >>>> On 2018/8/14 4:11, Jaegeuk Kim wrote: > >>>>> On 08/13, Chao Yu wrote: > >>>>>> Hi Jaegeuk, > >>>>>> > >>>>>> On 2018/8/11 2:56, Jaegeuk Kim wrote: > >>>>>>> This reverts the commit - "b93f771 - f2fs: remove writepages lock" > >>>>>>> to fix the drop in sequential read throughput. > >>>>>>> > >>>>>>> Test: ./tiotest -t 32 -d /data/tio_tmp -f 32 -b 524288 -k 1 -k 3 -L > >>>>>>> device: UFS > >>>>>>> > >>>>>>> Before - > >>>>>>> read throughput: 185 MB/s > >>>>>>> total read requests: 85177 (of these ~80000 are 4KB size requests). > >>>>>>> total write requests: 2546 (of these ~2208 requests are written in 512KB). > >>>>>>> > >>>>>>> After - > >>>>>>> read throughput: 758 MB/s > >>>>>>> total read requests: 2417 (of these ~2042 are 512KB reads). > >>>>>>> total write requests: 2701 (of these ~2034 requests are written in 512KB). > >>>>>> > >>>>>> IMO, it only impact sequential read performance in a large file which may be > >>>>>> fragmented during multi-thread writing. > >>>>>> > >>>>>> In android environment, mostly, the large file should be cold type, such as apk, > >>>>>> mp3, rmvb, jpeg..., so I think we only need to serialize writepages() for cold > >>>>>> data area writer. > >>>>>> > >>>>>> So how about adding a mount option to serialize writepage() for different type > >>>>>> of log, e.g. in android, using serialize=4; by default, using serialize=7 > >>>>>> HOT_DATA 1 > >>>>>> WARM_DATA 2 > >>>>>> COLD_DATA 4 > >>>>> > >>>>> Well, I don't think we need to give too many mount options for this fragmented > >>>>> case. How about doing this for the large files only like this? > >>>> > >>>> Thread A write 512 pages Thread B write 8 pages > >>>> > >>>> - writepages() > >>>> - mutex_lock(&sbi->writepages); > >>>> - writepage(); > >>>> ... > >>>> - writepages() > >>>> - writepage() > >>>> .... > >>>> - writepage(); > >>>> ... > >>>> - mutex_unlock(&sbi->writepages); > >>>> > >>>> Above case will also cause fragmentation since we didn't serialize all > >>>> concurrent IO with the lock. > >>>> > >>>> Do we need to consider such case? > >>> > >>> We can simply allow 512 and 8 in the same segment, which would not a big deal, > >>> when considering starvation of Thread B. > >> > >> Yeah, but in reality, there would be more threads competing in same log header, > >> so I worry that the effect of defragmenting will not so good as we expect, > >> anyway, for benchmark, it's enough. > > > > Basically, I think this is not a benchmark issue. :) It just reveals the issue > > much easily. Let me think about three cases: > > 1) WB_SYNC_NONE & WB_SYNC_NONE > > -> can simply use mutex_lock > > > > 2) WB_SYNC_ALL & WB_SYNC_NONE > > -> can use mutex_lock on WB_SYNC_ALL having >512 blocks, while WB_SYNC_NONE > > will skip writing blocks > > > > 3) WB_SYNC_ALL & WB_SYNC_ALL > > -> can use mutex_lock on WB_SYNC_ALL having >512 blocks, in order to avoid > > starvation. > > > > > > I've been testing the below. > > > > if (!S_ISDIR(inode->i_mode) && (wbc->sync_mode != WB_SYNC_ALL || > > get_dirty_pages(inode) <= SM_I(sbi)->min_seq_blocks)) { > > mutex_lock(&sbi->writepages); > > locked = true; > > Just cover buffered IO? how about covering Direct IO and atomic write as well? I'd expect direct IO does in-place-updates, and not sure whether we need to add another lock contention between buffered or direct IO. Atomic writes would be covered by ->min_seq_blocks. > > Thanks, > > > } > > > > Thanks, > > > >> > >> Thanks, > >> > >>> > >>>> > >>>> Thanks, > >>>> > >>>>> > >>>>> >From 4fea0b6e4da8512a72dd52afc7a51beb35966ad9 Mon Sep 17 00:00:00 2001 > >>>>> From: Jaegeuk Kim > >>>>> Date: Thu, 9 Aug 2018 17:53:34 -0700 > >>>>> Subject: [PATCH] f2fs: fix performance issue observed with multi-thread > >>>>> sequential read > >>>>> > >>>>> This reverts the commit - "b93f771 - f2fs: remove writepages lock" > >>>>> to fix the drop in sequential read throughput. > >>>>> > >>>>> Test: ./tiotest -t 32 -d /data/tio_tmp -f 32 -b 524288 -k 1 -k 3 -L > >>>>> device: UFS > >>>>> > >>>>> Before - > >>>>> read throughput: 185 MB/s > >>>>> total read requests: 85177 (of these ~80000 are 4KB size requests). > >>>>> total write requests: 2546 (of these ~2208 requests are written in 512KB). > >>>>> > >>>>> After - > >>>>> read throughput: 758 MB/s > >>>>> total read requests: 2417 (of these ~2042 are 512KB reads). > >>>>> total write requests: 2701 (of these ~2034 requests are written in 512KB). > >>>>> > >>>>> Signed-off-by: Sahitya Tummala > >>>>> Signed-off-by: Jaegeuk Kim > >>>>> --- > >>>>> Documentation/ABI/testing/sysfs-fs-f2fs | 8 ++++++++ > >>>>> fs/f2fs/data.c | 10 ++++++++++ > >>>>> fs/f2fs/f2fs.h | 2 ++ > >>>>> fs/f2fs/segment.c | 1 + > >>>>> fs/f2fs/super.c | 1 + > >>>>> fs/f2fs/sysfs.c | 2 ++ > >>>>> 6 files changed, 24 insertions(+) > >>>>> > >>>>> diff --git a/Documentation/ABI/testing/sysfs-fs-f2fs b/Documentation/ABI/testing/sysfs-fs-f2fs > >>>>> index 9b0123388f18..94a24aedcdb2 100644 > >>>>> --- a/Documentation/ABI/testing/sysfs-fs-f2fs > >>>>> +++ b/Documentation/ABI/testing/sysfs-fs-f2fs > >>>>> @@ -51,6 +51,14 @@ Description: > >>>>> Controls the dirty page count condition for the in-place-update > >>>>> policies. > >>>>> > >>>>> +What: /sys/fs/f2fs//min_seq_blocks > >>>>> +Date: August 2018 > >>>>> +Contact: "Jaegeuk Kim" > >>>>> +Description: > >>>>> + Controls the dirty page count condition for batched sequential > >>>>> + writes in ->writepages. > >>>>> + > >>>>> + > >>>>> What: /sys/fs/f2fs//min_hot_blocks > >>>>> Date: March 2017 > >>>>> Contact: "Jaegeuk Kim" > >>>>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c > >>>>> index 45f043ee48bd..f09231b1cc74 100644 > >>>>> --- a/fs/f2fs/data.c > >>>>> +++ b/fs/f2fs/data.c > >>>>> @@ -2132,6 +2132,7 @@ static int __f2fs_write_data_pages(struct address_space *mapping, > >>>>> struct f2fs_sb_info *sbi = F2FS_I_SB(inode); > >>>>> struct blk_plug plug; > >>>>> int ret; > >>>>> + bool locked = false; > >>>>> > >>>>> /* deal with chardevs and other special file */ > >>>>> if (!mapping->a_ops->writepage) > >>>>> @@ -2162,10 +2163,19 @@ static int __f2fs_write_data_pages(struct address_space *mapping, > >>>>> else if (atomic_read(&sbi->wb_sync_req[DATA])) > >>>>> goto skip_write; > >>>>> > >>>>> + if (!S_ISDIR(inode->i_mode) && > >>>>> + get_dirty_pages(inode) <= SM_I(sbi)->min_seq_blocks) { > >>>>> + mutex_lock(&sbi->writepages); > >>>>> + locked = true; > >>>>> + } > >>>>> + > >>>>> blk_start_plug(&plug); > >>>>> ret = f2fs_write_cache_pages(mapping, wbc, io_type); > >>>>> blk_finish_plug(&plug); > >>>>> > >>>>> + if (locked) > >>>>> + mutex_unlock(&sbi->writepages); > >>>>> + > >>>>> if (wbc->sync_mode == WB_SYNC_ALL) > >>>>> atomic_dec(&sbi->wb_sync_req[DATA]); > >>>>> /* > >>>>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > >>>>> index 375aa9f30cfa..098bdedc28bf 100644 > >>>>> --- a/fs/f2fs/f2fs.h > >>>>> +++ b/fs/f2fs/f2fs.h > >>>>> @@ -913,6 +913,7 @@ struct f2fs_sm_info { > >>>>> unsigned int ipu_policy; /* in-place-update policy */ > >>>>> unsigned int min_ipu_util; /* in-place-update threshold */ > >>>>> unsigned int min_fsync_blocks; /* threshold for fsync */ > >>>>> + unsigned int min_seq_blocks; /* threshold for sequential blocks */ > >>>>> unsigned int min_hot_blocks; /* threshold for hot block allocation */ > >>>>> unsigned int min_ssr_sections; /* threshold to trigger SSR allocation */ > >>>>> > >>>>> @@ -1133,6 +1134,7 @@ struct f2fs_sb_info { > >>>>> struct rw_semaphore sb_lock; /* lock for raw super block */ > >>>>> int valid_super_block; /* valid super block no */ > >>>>> unsigned long s_flag; /* flags for sbi */ > >>>>> + struct mutex writepages; /* mutex for writepages() */ > >>>>> > >>>>> #ifdef CONFIG_BLK_DEV_ZONED > >>>>> unsigned int blocks_per_blkz; /* F2FS blocks per zone */ > >>>>> diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c > >>>>> index 63fc647f9ac2..ffea2d1303bd 100644 > >>>>> --- a/fs/f2fs/segment.c > >>>>> +++ b/fs/f2fs/segment.c > >>>>> @@ -4131,6 +4131,7 @@ int f2fs_build_segment_manager(struct f2fs_sb_info *sbi) > >>>>> sm_info->ipu_policy = 1 << F2FS_IPU_FSYNC; > >>>>> sm_info->min_ipu_util = DEF_MIN_IPU_UTIL; > >>>>> sm_info->min_fsync_blocks = DEF_MIN_FSYNC_BLOCKS; > >>>>> + sm_info->min_seq_blocks = sbi->blocks_per_seg * sbi->segs_per_sec; > >>>>> sm_info->min_hot_blocks = DEF_MIN_HOT_BLOCKS; > >>>>> sm_info->min_ssr_sections = reserved_sections(sbi); > >>>>> > >>>>> diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c > >>>>> index be41dbd7b261..53d70b64fea1 100644 > >>>>> --- a/fs/f2fs/super.c > >>>>> +++ b/fs/f2fs/super.c > >>>>> @@ -2842,6 +2842,7 @@ static int f2fs_fill_super(struct super_block *sb, void *data, int silent) > >>>>> /* init f2fs-specific super block info */ > >>>>> sbi->valid_super_block = valid_super_block; > >>>>> mutex_init(&sbi->gc_mutex); > >>>>> + mutex_init(&sbi->writepages); > >>>>> mutex_init(&sbi->cp_mutex); > >>>>> init_rwsem(&sbi->node_write); > >>>>> init_rwsem(&sbi->node_change); > >>>>> diff --git a/fs/f2fs/sysfs.c b/fs/f2fs/sysfs.c > >>>>> index cd2e030e47b8..81c0e5337443 100644 > >>>>> --- a/fs/f2fs/sysfs.c > >>>>> +++ b/fs/f2fs/sysfs.c > >>>>> @@ -397,6 +397,7 @@ F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, batched_trim_sections, trim_sections); > >>>>> F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, ipu_policy, ipu_policy); > >>>>> F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, min_ipu_util, min_ipu_util); > >>>>> F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, min_fsync_blocks, min_fsync_blocks); > >>>>> +F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, min_seq_blocks, min_seq_blocks); > >>>>> F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, min_hot_blocks, min_hot_blocks); > >>>>> F2FS_RW_ATTR(SM_INFO, f2fs_sm_info, min_ssr_sections, min_ssr_sections); > >>>>> F2FS_RW_ATTR(NM_INFO, f2fs_nm_info, ram_thresh, ram_thresh); > >>>>> @@ -449,6 +450,7 @@ static struct attribute *f2fs_attrs[] = { > >>>>> ATTR_LIST(ipu_policy), > >>>>> ATTR_LIST(min_ipu_util), > >>>>> ATTR_LIST(min_fsync_blocks), > >>>>> + ATTR_LIST(min_seq_blocks), > >>>>> ATTR_LIST(min_hot_blocks), > >>>>> ATTR_LIST(min_ssr_sections), > >>>>> ATTR_LIST(max_victim_search), > >>>>> > >>> > >>> . > >>> > > > > . > >