Re: zero-copy TCP

From: Jes Sorensen (jes@linuxcare.com)
Date: Mon Sep 04 2000 - 10:20:24 EST


>>>>> "Ingo" == Ingo Molnar <mingo@elte.hu> writes:

Ingo> On Mon, 4 Sep 2000 kumon@flab.fujitsu.co.jp wrote:

>> The experiment showed the following prefetching could reduce 20-30%
>> of csum_partial_copy_generic() execution time.

Ingo> Please test it and post the numbers. csum_partial_copy_generic()
Ingo> already does prefetching - the real test would be to check
Ingo> lat_tcp and bw_tcp numbers over gigabit, with and without this
Ingo> patch applied. (the same numbers over localhost dont really
Ingo> count.) Eg. we had smart KNI-based memcpy routines as well, and
Ingo> it turned out that bw_tcp over gigabit actually got
Ingo> slower. [testing over 100mbit isnt enough obviously because x86
Ingo> CPUs csum much faster than that.]

Thats a surprise to me, I remember better performance when I played
with Doug's KNI patches back in the beginning.

Jes
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
Please read the FAQ at http://www.tux.org/lkml/



This archive was generated by hypermail 2b29 : Thu Sep 07 2000 - 21:00:18 EST