Re: More new schedule() results ...

Davide Libenzi (dlibenzi@maticad.it)
Sat, 12 Jun 1999 02:13:59 +0200 (CEST)

>this is what i suspected. If we are switching 450 threads that also do
>some real work then we are trashing the cache _badly_ already, so pure
>scheduling costs will not matter at all. Most systems (even loaded
>servers) have typically less than 5 runnable processes. So those systems
>will see 15% scheduling slowdown. Some applications might use many threads
>- for those cases your patch is a nice improvement.

Another couple of points.

1) Even with the two tasks sample the 15 % slodown is not evident
because the switching rate is statistically low.

2) My algo use the _same_ _sematics_ used by the old one but do it faster.

Probably You know better then me how many time schedule() is called in a
Linux workstation ( system calls ).
Lowering the time the cpu execute schedule() is not as lowering user mode
code because schedule() code is mostly interrupt protected.
This means a low speed in acknoledging IRQ and hence a worse system response
to events.

This is all,

Davide.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/