Increase BUFSIZ to 8192

[Adrian Chadd]

[snip]

The reason I ask about "why is it faster?" is because for embedded-y
things with low RAM we may not want that to happen due to memory
constraints. However, we may actually want to do some form of
autotuning on some platforms.

So, if it's underlying block size, maybe BUFSIZ isn't the thing to
tweak, but based on disk io buffer size.
If it's filling L1 or L2 cache with useful work, maybe auto-tune it
based on that.
If it's hiding interrupt latency over USB, then that should be addressed.
etc, etc.

Please don't take this as bikeshedding, I'd really like to see some
"this is why it's faster" analysis rather than just numbers thrown
around.



-adrian