Re: sendfile+zerocopy: fairly sexy (nothing to do with ECN)

[kuznet@xxxxxxxxxxxxx]

Hello!

> 2.4.1-pre10+zercopy, using read()/write():      38.1% CPU

write() on zc card is worse than normal write() by definition.
It generates split buffers.

Split buffers are more expensive and we have to pay for this.
You have paid too much for slow card though. 8)

Do you measure load correctly?


> 2.4.1-pre10+zercopy, using read()/write():      39.2% CPU    * hardware tx 
> checksums disabled

This is illegal combination of parameters. You force two memory accesses,
doing this. The fact that it does not add to load is dubious. 8)8)

Alexey