4.2 scheduler
Stanley Friesen
friesen at psivax.UUCP
Tue Dec 3 02:58:57 AEST 1985
In article <3043 at sun.uucp> guy at sun.uucp (Guy Harris) writes:
>
>> The net result is that a 4.2 system spends 30 to 50% of its time in the
>> kernel(verify this by running vmstat)!! This is quite high.
>
>Well, it *can* spend that much time in the kernel, depending on what you're
>doing. 30 to 50% isn't *that* high ...
Well, I consider 30% to be reasonable, but I find 50% and up
to be excessive, after all the machine is really there to execute
*user* code, not the kernal!
> the paper Berkeley put out on 4.2/4.3
>performance tuning indicated that 4.1 spent about 45% of its time in the
>kernel, 4.2 spent about 55% of its time there, and that they'd cut it back
>to 45% with their tuning.
>
Actually, on our system I noticed a greater change. Under 4.1
with a moderate load the system time averaged about 35%, under 4.2 it
jumped the the cited 55% value.
--
Sarima (Stanley Friesen)
UUCP: {ttidca|ihnp4|sdcrdcf|quad1|nrcvax|bellcore|logico}!psivax!friesen
ARPA: ttidca!psivax!friesen at rand-unix.arpa
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