From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cn.fujitsu.com ([222.73.24.84]:30785 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751826AbaANNQS (ORCPT ); Tue, 14 Jan 2014 08:16:18 -0500 Received: from fnstmail02.fnst.cn.fujitsu.com (tang.cn.fujitsu.com [127.0.0.1]) by tang.cn.fujitsu.com (8.14.3/8.13.1) with ESMTP id s0ECUOnC015721 for ; Tue, 14 Jan 2014 20:30:26 +0800 From: Miao Xie To: linux-btrfs@vger.kernel.org Subject: [PATCH V2 4/4] Btrfs: flush the dirty pages of the ordered extent aggressively during logging csum Date: Tue, 14 Jan 2014 20:31:52 +0800 Message-Id: <1389702712-26638-5-git-send-email-miaox@cn.fujitsu.com> In-Reply-To: <1389702712-26638-1-git-send-email-miaox@cn.fujitsu.com> References: <1389702712-26638-1-git-send-email-miaox@cn.fujitsu.com> Sender: linux-btrfs-owner@vger.kernel.org List-ID: The performance of fsync dropped down suddenly sometimes, the main reason of this problem was that we might only flush part dirty pages in a ordered extent, then got that ordered extent, wait for the csum calcucation. But if no task flushed the left part, we would wait until the flusher flushed them, sometimes we need wait for several seconds, it made the performance drop down suddenly. (On my box, it drop down from 56MB/s to 4-10MB/s) This patch improves the above problem by flushing left dirty pages aggressively. Test Environment: CPU: 2CPU * 2Cores Memory: 4GB Partition: 20GB(HDD) Test Command: # sysbench --num-threads=8 --test=fileio --file-num=1 \ > --file-total-size=8G --file-block-size=32768 \ > --file-io-mode=sync --file-fsync-freq=100 \ > --file-fsync-end=no --max-requests=10000 \ > --file-test-mode=rndwr run Signed-off-by: Miao Xie --- fs/btrfs/tree-log.c | 6 +++++- 1 files changed, 5 insertions(+), 1 deletions(-) diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c index 251e6f4..944701b 100644 --- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -3470,7 +3470,11 @@ static int log_one_extent(struct btrfs_trans_handle *trans, &ordered->flags)) continue; - wait_event(ordered->wait, ordered->csum_bytes_left == 0); + if (ordered->csum_bytes_left) { + btrfs_start_ordered_extent(inode, ordered, 0); + wait_event(ordered->wait, + ordered->csum_bytes_left == 0); + } list_for_each_entry(sum, &ordered->list, list) { ret = btrfs_csum_file_blocks(trans, log, sum); -- 1.7.1