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Date:   Tue, 25 May 2021 06:00:59 +0100
From:   Christoph Hellwig <hch@infradead.org>
To:     "Darrick J. Wong" <djwong@kernel.org>
Cc:     Josh Triplett <josh@joshtriplett.org>,
        Andreas Dilger <adilger@dilger.ca>,
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        NeilBrown <neilb@suse.com>
Subject: Re: How capacious and well-indexed are ext4, xfs and btrfs
 directories?
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On Mon, May 24, 2021 at 09:21:36PM -0700, Darrick J. Wong wrote:
> Synchronous discard is slow, even on NVME.

That really depends on the device.  Some are specifically optimized for
that workload due to customer requirements.