On Sat, 16 Sep 2000, Alexander Leidinger wrote:

> dnetc runns with idprio 31, system cvsupped around Sep 16, 11 CEST from
> a german mirror (it contains the idle fixes: src/sys/kern/kern_idle.c,v
> 1.4), complete build{world,kernel}.
> 
> ---snip---
> last pid:  1666;  load averages:  1.10,  1.11,  1.03    up 0+00:51:21  16:54:14

Perhaps it really is a system process :-[.  idprio on a pure cpu hog prevents
other user processes from running like a system process might do:

        idprio 31 sh -c "while :; do :; done"

System processes actually hang the entire system until they complete:

        dd if=/dev/random of=/dev/null bs=10m count=1

This takes 32 seconds on a Celeron 366 overclocked to 523, during
which time no other processes, including interrupt tasks, can run.
This is because the supergiant lock prevents context switching while
the i/o is being done.  There is nothing special about /dev/random
here except that it has a low transfer rate.

Bruce



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