From: Ben Hutchings <bhutchings@solarflare.com>
To: thomas yang <lampsu@gmail.com>
Cc: netdev@vger.kernel.org
Subject: Re: Ethernet CRC questions
Date: Wed, 30 Dec 2009 11:37:13 +0100 [thread overview]
Message-ID: <1262169433.2247.15.camel@localhost> (raw)
In-Reply-To: <f4f837ab0912292153l7086b631o6e0012d9049eecdb@mail.gmail.com>
On Wed, 2009-12-30 at 13:53 +0800, thomas yang wrote:
> 2009/12/30 Ben Hutchings <bhutchings@solarflare.com>:
> > On Wed, 2009-12-30 at 01:17 +0800, thomas yang wrote:
> >> How does Linux generate Ethernet CRC ?
> >> by the hardware (Ethernet controller) or use crc32_le() /
> >> crc32_be() ( lib/crc32.c ) ?
> >>
> >> P.S. my network card is rtl8139d , use 8139too driver
> >
> > The Ethernet frame CRC is normally generated and verified in hardware.
> > These library functions are needed for the few MACs that don't, or where
> > the same CRC function is used for some other purpose (e.g. as a hash
> > function for multicast filtering).
> >
>
> Does the Ethernet frame CRC (generate and verify in hardware) make
> the TX / RX rate a little smaller , and a longer end-to-end delay ?
Relative to what?
> Could I disable CRC appending / verifying in the network card driver
> on all of my nodes (machines) ?
Maybe if you want switches to discard everything you send...
Ben.
--
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.
next prev parent reply other threads:[~2009-12-30 10:37 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-12-29 17:17 Ethernet CRC questions thomas yang
2009-12-29 17:39 ` Ben Hutchings
2009-12-30 5:53 ` thomas yang
2009-12-30 6:43 ` Matti Aarnio
2009-12-30 10:37 ` Ben Hutchings [this message]
2009-12-30 16:19 ` thomas yang
2009-12-30 16:29 ` Ben Hutchings
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