pipes & ptys

[itschere@techfak.uni-bielefeld.de]

Hi everywhere,

  After having played a bit with the VDI version of MGR - and wondering
about why it is so slow when more than one window is open - I've hacked
a small experimental version of a window manager. Just one window which
can't be resized or removed, just to see what speed _can_ be achieved.

  Since some says it's so much optimized that I doubt I can get graphics
output any faster ;-) But still it is not very much faster than the MGR.

  When trying to track down the problem, I stumbled over the pipes through
which data gets passed. Normally they're resonably fast, say, fast enough.
But if I open a pipe as a pseudo tty and use 1 Bytes reads/writes - which
looks normal for shell i/o to me - I can't even get 1K/sec through it, and
all this on a TT. Is there really so much overhead in the tty routines in
tty.c? Mightn't this perhaps be worth improoving, since not just MGR or
my tricky window manager suffer from this bottleneck, but everything else
which works with pseudo ttys also...

  Anybody likes to start a discussion about that?

just curious,
TeSche
---
PS: If the above written looks weird, than that's because it probably IS ;-)
WhoDunnIt: Torsten Scherer (Schiller, TeSche...)
Technical Faculty, University of Bielefeld, Germany
EMail: itschere@techfak.uni-bielefeld.de / tesche@dave.hrz.uni-bielefeld.de