From: David Sterba <dsterba@suse.cz>
To: Xing Zhengjun <zhengjun.xing@linux.intel.com>
Cc: dsterba@suse.cz, "kernel test robot" <oliver.sang@intel.com>,
"Josef Bacik" <josef@toxicpanda.com>,
"David Sterba" <dsterba@suse.com>,
"René Rebe" <rene@exactcode.de>,
LKML <linux-kernel@vger.kernel.org>,
lkp@lists.01.org, lkp@intel.com, ying.huang@intel.com,
feng.tang@intel.com, linux-btrfs@vger.kernel.org
Subject: Re: [LKP] Re: [btrfs] e076ab2a2c: fio.write_iops -18.3% regression
Date: Thu, 14 Jan 2021 23:50:28 +0100 [thread overview]
Message-ID: <20210114225028.GF6430@twin.jikos.cz> (raw)
In-Reply-To: <979aee28-c603-a187-e03f-29957c7b94d6@linux.intel.com>
On Wed, Jan 13, 2021 at 01:58:18PM +0800, Xing Zhengjun wrote:
>
>
> On 1/12/2021 11:45 PM, David Sterba wrote:
> > On Tue, Jan 12, 2021 at 11:36:14PM +0800, kernel test robot wrote:
> >> Greeting,
> >>
> >> FYI, we noticed a -18.3% regression of fio.write_iops due to commit:
> >>
> >>
> >> commit: e076ab2a2ca70a0270232067cd49f76cd92efe64 ("btrfs: shrink delalloc pages instead of full inodes")
> >> https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master
> >>
> >>
> >> in testcase: fio-basic
> >> on test machine: 192 threads Intel(R) Xeon(R) CPU @ 2.20GHz with 192G memory
> >> with following parameters:
> >>
> >> disk: 1SSD
> >> fs: btrfs
> >> runtime: 300s
> >> nr_task: 8
> >> rw: randwrite
> >> bs: 4k
> >> ioengine: sync
> >> test_size: 256g
> > Though I do a similar test (emulating bit torrent workload), it's a bit
> > extreme as it's 4k synchronous on a huge file. It always takes a lot of
> > time but could point out some concurrency issues namely on faster
> > devices. There are 8 threads possibly competing for the same inode lock
> > or other locks related to it.
> >
> > The mentioned commit fixed another perf regression on a much more common
> > workload (untgrring files), so at this point drop in this fio workload
> > is inevitable.
>
> Do you have a plan to fix it? Thanks.
My plan is to find somebody who will fix it. Thanks.
prev parent reply other threads:[~2021-01-14 22:53 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-12 15:36 [btrfs] e076ab2a2c: fio.write_iops -18.3% regression kernel test robot
2021-01-12 15:45 ` David Sterba
2021-01-13 5:58 ` [LKP] " Xing Zhengjun
2021-01-14 22:50 ` David Sterba [this message]
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