From: "René Rebe" <rene@exactcode.de>
To: linux-btrfs@vger.kernel.org
Subject: [BUG] 500-2000% performance regression w/ 5.10
Date: Mon, 21 Dec 2020 20:45:50 +0100 [thread overview]
Message-ID: <B4BB2DCB-C438-4871-9DDD-D6FB0E6E4F1B@exactcode.de> (raw)
Hey there,
as a long time btrfs user I noticed some some things became very slow
w/ Linux kernel 5.10. I found a very simple test case, namely extracting
a huge tarball like:
tar xf /usr/src/t2-clean/download/mirror/f/firefox-84.0.source.tar.zst
Why my external, USB3 road-warrior SSD on a Ryzen 5950x this
went from ~15 seconds w/ 5.9 to nearly 5 minutes in 5.10, or 2000%
To rule out USB, I also tested a brand new PCIe 4.0 SSD, with
a similar, albeit not as shocking regression from 5.2 seconds
to ~34 seconds or∫~650%.
Somehow testing that in a VM did over virtio did not produce
as different results, although it was already 35 seconds slow
with 5.9.
# first bad commit: [38d715f494f2f1dddbf3d0c6e50aefff49519232]
btrfs: use btrfs_start_delalloc_roots in shrink_delalloc
Now just this single commit does obviously not revert cleanly,
and I did not have the time today to look into the rather more
complex code today.
I hope this helps improve this for the next release, maybe you
want to test on bare metal, too.
Greetings,
René https://youtu.be/NhUMdvLyKJc
--
ExactCODE GmbH, Lietzenburger Str. 42, DE-10789 Berlin, https://exactcode.com
https://exactscan.com | https://ocrkit.com | https://t2sde.org | https://rene.rebe.de
next reply other threads:[~2020-12-21 20:02 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-21 19:45 René Rebe [this message]
2020-12-22 8:28 ` [BUG] 500-2000% performance regression w/ 5.10 Qu Wenruo
2020-12-22 9:12 ` Rene Rebe
2020-12-23 3:14 ` Josef Bacik
2020-12-23 19:41 ` Josef Bacik
2020-12-23 20:31 ` Holger Hoffstätte
2020-12-23 20:34 ` Josef Bacik
2020-12-24 18:09 ` Josef Bacik
2020-12-24 21:11 ` René Rebe
2020-12-26 12:24 ` Nikolay Borisov
2020-12-26 15:30 ` Rene Rebe
2020-12-26 12:23 ` Nikolay Borisov
2021-01-04 1:15 ` Chris Murphy
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=B4BB2DCB-C438-4871-9DDD-D6FB0E6E4F1B@exactcode.de \
--to=rene@exactcode.de \
--cc=linux-btrfs@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox