> > currently, when doing tcp bulk send and send buffer is filled up,
> > we ends up with per-ack small copyin()s rather than page loaning.
> >
> > the attached patch is to increase chances to use loaning by giving it
> > some "bonus" buffer space.
> > in my test environment, it actually yields some noticable  
> > improvements.
> 
> How much improvement have you measured?
> 
> It seems reasonable to me, even though it seems we could end up using  
> more than the sbspace available in the socket buffer, because we  
> aren't actually allocating new buffers and filling them.
> 
> -- thorpej

i haven't committed this change because i found it can beat OOB data.
it can be worked around by giving more space for OOB data,
say, 4096 bytes for loaning and 4096+1024 for OOB data.
but i'm not entirely happy with it.
does anyone have an idea to solve this more cleanly?

YAMAMOTO Takashi