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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED 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 814F6C46464 for ; Wed, 15 Aug 2018 01:52:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 28CEE21709 for ; Wed, 15 Aug 2018 01:52:53 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 28CEE21709 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=huawei.com 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 S1726749AbeHOEmr (ORCPT ); Wed, 15 Aug 2018 00:42:47 -0400 Received: from szxga07-in.huawei.com ([45.249.212.35]:52102 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725831AbeHOEmr (ORCPT ); Wed, 15 Aug 2018 00:42:47 -0400 Received: from DGGEMS408-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id 71209979565C1; Wed, 15 Aug 2018 09:52:47 +0800 (CST) Received: from [127.0.0.1] (10.134.22.195) by DGGEMS408-HUB.china.huawei.com (10.3.19.208) with Microsoft SMTP Server id 14.3.399.0; Wed, 15 Aug 2018 09:52:47 +0800 Subject: Re: [f2fs-dev] [PATCH v3] f2fs: fix performance issue observed with multi-thread sequential read To: Jaegeuk Kim CC: , 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> From: Chao Yu Message-ID: <167ce8f1-ee4d-2ffc-3518-32850465cd0c@huawei.com> Date: Wed, 15 Aug 2018 09:52:47 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20180814172837.GD56510@jaegeuk-macbookpro.roam.corp.google.com> Content-Type: text/plain; charset="windows-1252" Content-Language: en-US Content-Transfer-Encoding: 7bit X-Originating-IP: [10.134.22.195] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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? 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), >>>>> >>> >>> . >>> > > . >