From: Michael Bromilow <stick.insects22@gmail.com>
To: Boris Burkov <boris@bur.io>, Chris Mason <clm@meta.com>
Cc: Christoph Hellwig <hch@infradead.org>,
Linux regressions mailing list <regressions@lists.linux.dev>,
Sergei Trofimovich <slyich@gmail.com>,
Josef Bacik <josef@toxicpanda.com>,
Christopher Price <pricechrispy@gmail.com>,
anand.jain@oracle.com, clm@fb.com, dsterba@suse.com,
linux-btrfs@vger.kernel.org
Subject: Re: [6.2 regression][bisected]discard storm on idle since v6.1-rc8-59-g63a7cb130718 discard=async
Date: Mon, 10 Apr 2023 03:03:37 +0100 [thread overview]
Message-ID: <6a54fa77-9a0c-8844-2eb0-b65591e97a16@gmail.com> (raw)
In-Reply-To: <20230404185138.GB344341@zen>
On 04/04/2023 19:51, Boris Burkov wrote:
> On Tue, Apr 04, 2023 at 02:15:38PM -0400, Chris Mason wrote:
>> So, honestly from my POV the async discard is best suited to consumer
>> devices. Our defaults are probably wrong because no matter what you
>> choose there's a drive out there that makes it look bad. Also, laptops
>> probably don't want the slow dribble.
>
> Our reasonable options, as I see them:
> - back to nodiscard, rely on periodic trims from the OS.
> - leave low iops_limit, drives stay busy unexpectedly long, conclude that
> that's OK, and communicate the tuning/measurement options better.
> - set a high iops_limit (e.g. 1000) drives will get back to idle faster.
> - change an unset iops_limit to mean truly unlimited async discard, set
> that as the default, and anyone who cares to meter it can set an
> iops_limit.
>
> The regression here is in drive idle time due to modest discard getting
> metered out over minutes rather than dealt with relatively quickly. So
> I would favor the unlimited async discard mode and will send a patch to
> that effect which we can discuss.
Will power usage be taken into consideration? I only noticed this regression
myself when my laptop started to draw a constant extra ~10W from the constant
drive activity, so I imagine other laptop users would also prefer a default
which avoids this if possible. If "relatively quickly" means anything more
than a few seconds I could see that causing rather significant battery life
reductions.
- Michael
next prev parent reply other threads:[~2023-04-10 2:03 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-20 22:40 [6.2 regression][bisected]discard storm on idle since v6.1-rc8-59-g63a7cb130718 discard=async Christopher Price
2023-03-21 21:26 ` Josef Bacik
2023-03-22 8:38 ` Christoph Hellwig
2023-03-23 22:26 ` Sergei Trofimovich
2023-04-04 10:49 ` Linux regression tracking (Thorsten Leemhuis)
2023-04-04 16:04 ` Christoph Hellwig
2023-04-04 16:20 ` Roman Mamedov
2023-04-04 16:27 ` Christoph Hellwig
2023-04-04 23:37 ` Damien Le Moal
2023-04-04 18:15 ` Chris Mason
2023-04-04 18:51 ` Boris Burkov
2023-04-04 19:22 ` David Sterba
2023-04-04 19:39 ` Boris Burkov
2023-04-05 8:17 ` Linux regression tracking (Thorsten Leemhuis)
2023-04-10 2:03 ` Michael Bromilow [this message]
2023-04-11 17:52 ` David Sterba
2023-04-11 18:15 ` Linux regression tracking (Thorsten Leemhuis)
2023-04-04 19:08 ` Sergei Trofimovich
2023-04-05 6:18 ` Christoph Hellwig
2023-04-05 12:01 ` Chris Mason
2023-04-04 18:23 ` Boris Burkov
2023-04-04 19:12 ` Sergei Trofimovich
-- strict thread matches above, loose matches on Subject: below --
2023-03-01 19:30 Sergei Trofimovich
2023-03-02 8:04 ` Linux regression tracking #adding (Thorsten Leemhuis)
2023-04-04 10:52 ` Linux regression tracking #update (Thorsten Leemhuis)
2023-04-21 13:56 ` Linux regression tracking #update (Thorsten Leemhuis)
2023-03-02 9:12 ` Anand Jain
2023-03-02 10:54 ` Sergei Trofimovich
2023-03-15 11:44 ` Linux regression tracking (Thorsten Leemhuis)
2023-03-15 16:34 ` Sergei Trofimovich
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