From: David Laight <David.Laight@ACULAB.COM>
To: 'Krzysztof Kozlowski' <krzk@kernel.org>,
Pantelis Antoniou <pantelis.antoniou@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
"linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Cc: Eric Biggers <ebiggers3@gmail.com>
Subject: RE: [PATCH] net: ethernet: fs-enet: Use generic CRC32 implementation
Date: Tue, 24 Jul 2018 11:05:59 +0000 [thread overview]
Message-ID: <5ef968e1cb2a473cad97f6bfead369ca@AcuMS.aculab.com> (raw)
In-Reply-To: <20180723162020.6221-1-krzk@kernel.org>
From: Krzysztof Kozlowski
> Sent: 23 July 2018 17:20
> Use generic kernel CRC32 implementation because it:
> 1. Should be faster (uses lookup tables),
Are you sure?
The lookup tables are unlikely to be in the data cache and
the 6 cache misses kill performance.
(Not that it particularly matters when setting up multicast hash tables).
> 2. Removes duplicated CRC generation code,
> 3. Uses well-proven algorithm instead of coding it one more time.
...
>=20
> Not tested on hardware.
Have you verified that the old and new functions give the
same result for a few mac addresses?
It is very easy to use the wrong bits in crc calculations
or generate the output in the wrong bit order.
=09David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1=
PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2018-07-24 15:05 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-23 16:20 [PATCH] net: ethernet: fs-enet: Use generic CRC32 implementation Krzysztof Kozlowski
2018-07-24 11:05 ` David Laight [this message]
2018-07-24 11:11 ` Krzysztof Kozlowski
2018-07-24 11:22 ` David Laight
2018-07-25 20:42 ` David Miller
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