Re: [9front] iounit: bump it across the board

[ori@eigenstate.org]

Quoth ori@eigenstate.org:
> Quoth noam@pixelhero.dev:
> > Quoth ori@eigenstate.org:
> > > This patch bumps up the iounit in the kernel to 32k, and
> > > introduces the IOUNIT constant to take advantage of it.
> > 
> > Any reason I shouldn't bump it to 1M or something locally?
> > (in the kernel and, in userspace, in non-libthread applications)
> > 
> > - Noam Preil
> > 
> 
> Try it out, but keep in mind that on a slower connection,
> you have to wait for the entire iounit to get sent before
> you can send the next request -- so, eg, tethering over
> wifi means that your file IO needs to go through fully
> before your next mouse message can get sent.
> 

phrased poorly -- but, if your mouse and file system share
a 9p channel (ie, exportfs), then large messages will block
all other communication.

the other reason is that you can have a lot of in flight
9p buffers at once; up to 64k per connection. Most of the
time there will be fewer, but not always. But even a few
hundred 1 meg buffers is a lot of memory on smaller modern
systems.