Re: TSO thruput is low !

From: Nagendra Singh Tomar (nagendra_tomar@adaptec.com)
Date: Tue Aug 12 2003 - 19:55:22 EST


I used Jamal's ttcp-sf (TTCP sendfiled ) also, but no change again.
I did'nt understand how sendfile could have helped here. AFAIK
sendfile()
will just reduce the CPU utilization further as it avoids a user-to-kernel
copy. It can increase throughput only in case when it is limited by
getting the data to send (an FTP server reading from a file on the hard
disk). If without
TSO we are getting a healthy 102MBps then thruput should not fall with
TSO.
Is it possible that in TSO case the kernel is keeping the application
provided data longer in a bid to accumulate it to make larger payloads
that can then be TSO'ed to the chip. Just a guess !

FYKI, I have also tried with 256KB send buffer size and the results are
same.

Thanx,
tomar


On Tue, 12 Aug 2003, David S. Miller wrote:

> On Tue, 12 Aug 2003 05:01:21 +0530 (IST)
> Nagendra Singh Tomar <nagendra_tomar@xxxxxxxxxxx> wrote:
>
> > Any suggestions ?
>
> Try again with an application that uses sendfile().
>

-
To unsubscribe from this list: send the line "unsubscribe linux-net" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html