On Fri, 22 Nov 2013 10:59:23 -0500
Peter Hurley <peter@xxxxxxxxxxxxxxxxxx> wrote:
> Distinguish if caller is n_tty_poll() or n_tty_read(), and
> set the read/wakeup threshold accordingly.
That looks very wrong to me. The poll() and read() wakeup should always
match. In addition if MIN_CHAR is set without a timeout then it should not
wake up until MIN_CHAR characters are present. The MIN_CHAR feature is
used by various (these days obscure) protocols to optimise block transfer
rates.
Changing this is also a userspace visible API change.
So NAK.
The underlying intention of the system (and SYS5.4) is that you can do
MIN_CHAR = 64
alarm(some_timeout)
while(1) {
poll();
events
read(chunksized blocks)
}
while it's hardly as critical with modern fast hardware its still the API
and necessary to avoid SWS type behaviours in the queue turning it from
block/syscall to byte I/O.
Alan
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