Re: pty(4) 1024 bytes buffer limit

[Thor Lancelot Simon <tls%panix.com@localhost>]

On Thu, Sep 08, 2011 at 11:26:29AM -0400, Matthew Mondor wrote:
> 
> It would be nice to for instance be able to use an MTU of 3000 so that
> there are less context switches, but unfortunately tracing the
> processes show that 1024 bytes are read from the pty devices at most.

Are you sure using an MTU of 3000 would do much of anything?  Since
almost all peers are connected by Ethernet somewhere along the line,
you are unlikely to ever see packets larger than 1500 minus Ethernet
framing size.

How did you determine that the bottleneck for your application was
context switches?  That the 1024-byte read size you're seeing is
actually internal to the tty layer or ppp rather than application
imposed in userspace?

Thor