Re: Very high bandwith packet based interface and performance problems

From: Rick Jones (raj@cup.hp.com)
Date: Wed Feb 21 2001 - 20:46:25 EST


Alan Cox wrote:
>
> > that because the kernel was getting 99% of the cpu, the application was
> > getting very little, and thus the read wasn't happening fast enough, and
>
> Seems reasonable
>
> > This is NOT what I'm seeing at all.. the kernel load appears to be
> > pegged at 100% (or very close to it), the user space app is getting
> > enough cpu time to read out about 10-20Mbit, and FURTHERMORE the kernel
> > appears to be ACKING ALL the traffic, which I don't understand at all
> > (e.g. the transmitter is simply blasting 300MBit of tcp unrestricted)
>
> TCP _requires_ the remote end ack every 2nd frame regardless of progress.

um, I thought the spec says that ACK every 2nd segment is a SHOULD not a
MUST?

rick jones

-- 
ftp://ftp.cup.hp.com/dist/networking/misc/rachel/
these opinions are mine, all mine; HP might not want them anyway... :)
feel free to email, OR post, but please do NOT do BOTH...
my email address is raj in the cup.hp.com domain...
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This archive was generated by hypermail 2b29 : Fri Feb 23 2001 - 21:00:26 EST