Re: Still not sexy! (Re: sendfile+zerocopy: fairly sexy (nothing to do with ECN)

[Ingo Molnar <mingo@xxxxxxx>]

On Wed, 31 Jan 2001, Malcolm Beattie wrote:

> Without the raised tcp_wmem setting I was getting 81 MByte/s. With
> tcp_wmem set as above I got 86 MByte/s. Nice increase. Any other
> setting I can tweak apart from {r,w}mem_max and tcp_{w,r}mem? The CPU
> on the client (350 MHz PII) is the bottleneck: gensink4 maxes out at
> 69 Mbyte/s pulling TCP from the server and 94 Mbyte/s pushing. (The
> other system, 733 MHz PIII pushes >100MByte/s UDP with ttcp but the
> client drops most of it).

you can speed up the client significantly by using the MSG_TRUNC option
('truncate message'). It will zap incoming data without copying it into
user-space. (you can use this for the 'bulk transfer' part - the initial
protocol handling code needs to see the actual data.) This way you should
be able to saturate the server even more.

        Ingo