Re: xterm scrolling speed - scheduling weirdness in 2.6 ?!

From: Valdis . Kletnieks
Date: Sun Jan 04 2004 - 18:45:20 EST


On Mon, 05 Jan 2004 00:33:12 +0100, Willy Tarreau said:

> at a time. I have yet to understand why 'ls|cat' behaves
> differently, but fortunately it works and it has already saved

I suspect that ls and cat do different buffering to their outputs, and/or the
fact there's now 4 processes (ls, cat, xterm, Xserver) rather than just 3. End
result is that things wake up in a different order and happen to schedule
better. (For instance, ls may be able to make progress while cat is blocked
waiting for the xterm to read the next block, etc). I remember at least some
versions of 'dd' would fork off a sub-process so there would be a reader side
and a writer side with a shared memory buffer, for just that reason.

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