Re: [patch] e1000 TSO parameter

[Anton Blanchard <anton@xxxxxxxxx>]

Hi,

> > So we get almost 15% of throughput drop.  This was with plain "netkit
> > fptd".  AFAIK, it does a simple read/write loop (not sendfile()).

We've been seeing rather variable results for TSO as well. With TSO off
netperf TCP_STREAM will hit line speed and stay there. With TSO on
some runs will hit line speed and others will be about 100Mbit/sec
slower.

> When we use TSO for non-sendfile() applications it really
> stresses memory allocations.  We do these 64K+ kmalloc()'s
> for each packet we construct.

Yep we definitely noticed much more higher allocations when watching
/proc/slab. Playing around with slab tuning didnt seem to help.

Anton