From: "Fabian Grünbichler" <f.gruenbichler@proxmox.com>
To: Dietmar Maurer <dietmar@proxmox.com>,
Proxmox Backup Server development discussion
<pbs-devel@lists.proxmox.com>
Subject: Re: [pbs-devel] [PATCH proxmox-backup] backup/verify: improve speed by sorting chunks by inode
Date: Thu, 15 Apr 2021 09:19:56 +0200 [thread overview]
Message-ID: <1618470962.eg8dxuk2ne.astroid@nora.none> (raw)
In-Reply-To: <1688290929.3134.1618418686372@webmail.proxmox.com>
On April 14, 2021 6:44 pm, Dietmar Maurer wrote:
>> zfs with single spinner + fast special device, with a (not counted ;))
>> warmup run and everything fitting into cache:
>>
>> Benchmark #1: stock
>> Time (mean ± σ): 21.407 s ± 0.819 s [User: 20.1 ms, System: 15.2 ms]
>> Range (min … max): 21.070 s … 23.078 s 6 runs
>>
>> Benchmark #2: patched
>> Time (mean ± σ): 47.119 s ± 0.018 s [User: 29.5 ms, System: 15.1 ms]
>> Range (min … max): 47.107 s … 47.154 s 6 runs
>>
>> Summary
>> 'stock' ran
>> 2.20 ± 0.08 times faster than 'patched'
>
> I assume you have about 3000 chunks? On XFS, I can do 3000 stat() calls per second (after cache cleared).
> So why the hell are stat calls that slow on ZFS with special device? Or what causes that delay (stat or sort)?
13432 chunks. the run you quoted is with everything in ARC, so this is
not even hitting disk (neither special nor regular vdev). I haven't
profiled what exactly is the cause of the slowdown.
next prev parent reply other threads:[~2021-04-15 7:20 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-14 16:44 Dietmar Maurer
2021-04-15 7:19 ` Fabian Grünbichler [this message]
-- strict thread matches above, loose matches on Subject: below --
2021-04-14 7:17 Dietmar Maurer
2021-04-13 14:35 Dominik Csapak
2021-04-14 13:24 ` Fabian Grünbichler
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=1618470962.eg8dxuk2ne.astroid@nora.none \
--to=f.gruenbichler@proxmox.com \
--cc=dietmar@proxmox.com \
--cc=pbs-devel@lists.proxmox.com \
/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