Is clock() what you mean?
On Mon, 28 Nov 2005, Adrian May wrote:
Hi folks,
I don't know whether I have to hack the kernel for this or not, but figured
you lot would know.
I want very accurate timing inside my app. That means, my process will ask
for it's exact age at various times. This age should not include times when
some other process was scheduled, but it should include the overhead of the
timing itself, which gets done by my process. I want it to be high
performance because I'll be doing it very often indeed. Function-level
profiling is not enough because I need the time spent inside one specific
function in particular, but separated out according to a parameter to that
function. (Basically it's a VM that hosts zillions of tiny scripts and wants
to keep perfect accounts about time used by all of them and that used by the
VM itself).
I think that poking about in /proc would be too slow, but I bet the kernel
knows how many jiffies my process has had, and if I could figure out what
time (in usecs) my current slice started I could use the usec timer to figure
out how old this slice is and work out the final answer that way. Or maybe
there's a better strategy. I need it really accurate and fast though -
ideally in processor cycles, but I somehow need to exclude the times I'm
scheduled out.
Any ideas?
Thanks in advance,
Adrian.
BTW - I'll also need interval timers to terminate greedy scripts but they
don't have to be all that accurate.
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