From: hch@infradead.org (Christoph Hellwig)
Subject: [PATCH] nvme: set physical block size to value discovered in Identify Namespace
Date: Wed, 20 Sep 2017 10:48:14 -0700 [thread overview]
Message-ID: <20170920174814.GA2556@infradead.org> (raw)
In-Reply-To: <20170920174842.GB1379@localhost.localdomain>
On Wed, Sep 20, 2017@01:48:42PM -0400, Keith Busch wrote:
> I think what you're wanting to say is:
>
> The physical block size will default to the logical block size unless
> otherwise specified. While NVMe doesn't provide a way to discover the
> physical block size, the format with best relative performance is a
> good indicator as to the underlying block size.
I don't like this at all. It's a really nasty guesswork. If you need
this to get reasonable performance out of a specific device please
quirk it.
NVMe doesn't have the legacy issues that require 4k physical sectors
and 512 logical like ATA, so if a device really prefers 4k sectors
it should skip with 4k format by default instead of doing the logical /
physical dance. Especially that a "physical" blocksize that Linux
could actually deal with (<= 4k) is a complete lie for flash anyway.
next prev parent reply other threads:[~2017-09-20 17:48 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-20 17:06 [PATCH] nvme: set physical block size to value discovered in Identify Namespace Andrzej Jakowski
2017-09-20 17:48 ` Keith Busch
2017-09-20 17:48 ` Christoph Hellwig [this message]
2017-09-20 19:07 ` Keith Busch
2017-09-20 20:01 ` Martin K. Petersen
2017-09-20 20:10 ` Christoph Hellwig
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