Re: [PARPORT] ieee1284 compat mode performances

Philip Blundell (
Tue, 06 Apr 1999 22:58:18 +0100

>When my Dad start a printing from his client my machine goes _down_. My
>mouse stall completly and chars appear on the screen after msec of delay.
>I am quite sure the overkill is the udelay().

FWIW, I think this time is now adjustable with sysctl. Whatever behaviour we
choose for this it will always be possible to invent a situation where it
goes wrong. Just disabling the loop may fix things for you (at least, it may
get your machine performance back) but it will hurt printing speed for at
least some people.

I agree that having thought about the numbers a bit, 500us is possibly
slightly on the high side as the default value. Try winding it down to about
50 or 100 and see if that improves matters. You could also try adding a check
for resched_needed somewhere in parport_ieee1284_write_compat if there isn't
one already.

Are you using polling or interrupts there?


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This archive was generated by hypermail 2.0b3 on Tue 06 Apr 1999 - 18:06:25 EDT