>> It seems that the overhead is unnoticeable if disabled, very visible
>> for lightweight functions and heavy callers. Almost unnoticeable for
>> more compute intensive functions.
>
> The very high system times seem odd. Maybe you have a machine with
> slow gettimeofday()?
>
So it seems (on Ubuntu 7.04). Reran the benchmark on another system and
got more reasonable results:
"none" usr sys total
dummy 15.9 0.68 16.58
rfact 39.37 0.07 39.44
ifact 12.89 0.01 12.9
"all" usr sys total diff x
dummy 20.82 4.44 25.26 1.52
rfact 45.17 4.17 49.34 1.25
ifact 12.92 0.03 12.96 1.00
Regards,
Martin