kernel cpu entries
Pete French
petefrench at ticketswitch.com
Thu Dec 15 12:05:40 PST 2005
> I can't see anything in the kernel source code to explain it. Since
> you don't mention actual times, is the difference statistically
> significant? (see src/tools/tools/ministat)
Ministat says: Difference at 95.0% confidence
The second set are always smaller than the first set no matter how many
times I run it, so it is repeatable. I only wrote down a few of the raw
results, but here are a set of three outputs from time (real, user, system)
for i686 alone and i586+i686.
i686:
496.26 857.54 43.05
501.00 858.03 42.40
517.04 857.90 42.91
i586+i686:
483.70 852.70 51.77
484.93 853.54 50.60
489.26 855.23 46.82
It is a shame I didnt do any without the -j2 on. I suspect that it would show
a slowdown, as the user+system times are always lower on the i686 on its
own. But when running in parallel you actually get a speedup in elapsed
time, even though you are seeing a slowdown on each processor individually.
So does adding in i586 somehow increase the potential for parallelism
somehow ? Thats the only thing I can think of....
-pete.
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