2002-10-16 14:43:41

by Roy Sigurd Karlsbakk

Subject: [Q] e1000 hardware checksumming support?

hi

Can Linux 2.4 use the hardware checksumming in the e1000 adapter? I mean .. my
server is using most of it's time to csum_partial_copy_generic (and that's
the checksum? or am I wrong?)

[root@vs1 /]# readprofile | sort -rn +2 | head -30
124855 default_idle 1950.8594
33335 handle_IRQ_event 231.4931
47663 csum_partial_copy_generic 205.4440
13144 e1000_intr 136.9167
6526 fget 101.9688
6474 system_call 101.1562
4620 sock_poll 96.2500
10125 skb_release_data 90.4018

thanks

roy
--
Roy Sigurd Karlsbakk, Datavaktmester
ProntoTV AS - http://www.pronto.tv/
Tel: +47 9801 3356

Computers are like air conditioners.
They stop working when you open Windows.

2002-10-16 21:39:44

by David Miller

Subject: Re: [Q] e1000 hardware checksumming support?

From: Roy Sigurd Karlsbakk <[email protected]>
Date: Wed, 16 Oct 2002 16:54:05 +0200

Can Linux 2.4 use the hardware checksumming in the e1000 adapter?

Two things:

1) On output you only get checksumming if your applications
use sendfile()

2) On input, since we have to copy the data anyways, we use
csum_partial_copy because it costs the same as a memcpy.

Actually, on some x86 cpus the checksum+copy is faster
than the memcpy, but that is being fixed in current 2.5.x