Jim Sibley writes:
> I am trying to find out how fast I can push several OSA GBX cards under
> SuSE 2.2.16. I have been able to double the FTP rate by changing the MTU
> size to 9000. This also benefits my 4k transaction processing. What other
> parameters can I adjust in TCP/IP to reduce delays and increase "buffer"
> sizes.
>
> The same question for 2.4.7.
Start with
# echo 262144 > /proc/sys/net/core/wmem_max
# echo 262144 > /proc/sys/net/core/rmem_max
to raise the maximum read/write buffer size internally from 64K to 256K.
Some performance improvements depend on support from the application too
(don't try changing rmem_default and wmem_default unless you really
know what you're doing). Another big improvement is possible if your
ftpd supports using sendfile() which allows for zerocopy (well,
(n-1)-copy since you need specific combinations of networking hardware
and drivers to get true zero-copy). One ftp daemon which supports
sendfile is vsftpd ("Very Secure ftpd") written by Chris Evans. I'm not
sure if proftpd supports it out of the box: it didn't used to but I've
a feeling modern versions might. (Needless to say, don't use wuftpd...).
Depending how desperate you are, we can probably keep raising the
performance if necessary. (Reminds me of Larry McVoy's challenge: he
guarantees to achieve any disk I/O throughput you like provided that
you pay for the hardware and let him keep it afterwards :-).
--Malcolm
--
Malcolm Beattie <[EMAIL PROTECTED]>
Linux Technical Consultant
IBM EMEA Enterprise Server Group...
...from home, speaking only for myself
