From: David Disseldorp <ddiss@suse.de>
To: Qu Wenruo <quwenruo.btrfs@gmx.com>
Cc: fstests@vger.kernel.org, Qu Wenruo <wqu@suse.com>
Subject: Re: [PATCH 0/5] btrfs/282: resolve intermittent failures
Date: Fri, 8 Dec 2023 00:49:02 +1100 [thread overview]
Message-ID: <20231208004902.3df2bed2@echidna> (raw)
In-Reply-To: <949dd5fe-560f-4986-b653-c84aa9afd778@gmx.com>
On Thu, 7 Dec 2023 20:19:00 +1030, Qu Wenruo wrote:
> On 2023/12/7 17:50, David Disseldorp wrote:
> > btrfs/282 fails intermittently under some circumstances. This patchset
> > adds dmdelay to make storage latencies more uniform and slightly
> > increases throttled rate tolerances.
>
> My concern using dm_delay is, is the delay per-merged-bio or something else?
>
> If the delay is only per-bio (after merge), then I'm afraid it would not
> be good enough.
The dmdelay device presents itself as a regular block device, so I think
delay_map()->delay_bio() handling comes after any merges.
> The bio plug we use in scrub can have much higher chance to result a
> difference in the scrub speed.
>
> We may want a delay behavior which can take bio size into consideration
> at least.
Should we manipulate it a bit by fiddling with queue/max_sectors_kb and
queue/nomerges?
Thanks, David
next prev parent reply other threads:[~2023-12-07 13:49 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-12-07 7:20 [PATCH 0/5] btrfs/282: resolve intermittent failures David Disseldorp
2023-12-07 7:20 ` [PATCH 1/5] common/dmdelay: remove DELAY_X enums David Disseldorp
2023-12-07 7:20 ` [PATCH 2/5] btrfs/282: append scrub status output to 282.full David Disseldorp
2023-12-07 9:46 ` Qu Wenruo
2023-12-07 7:20 ` [PATCH 3/5] btrfs/282: dmdelay scrub I/O to fix intermittent failures David Disseldorp
2023-12-07 7:20 ` [PATCH 4/5] btrfs/282: reduce scrub dataset size David Disseldorp
2023-12-07 7:20 ` [PATCH 5/5] btrfs/282: increase throttled scrub rate tolerance David Disseldorp
2023-12-07 9:49 ` [PATCH 0/5] btrfs/282: resolve intermittent failures Qu Wenruo
2023-12-07 13:49 ` David Disseldorp [this message]
2023-12-07 20:02 ` Qu Wenruo
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