Question on meaning of time values....

[luis@postgres.Berkeley.EDU (Luis Miguel)]

I am using the function excl::get-internal-run-times to get as accurate
as possible the running time of a function. The function returns 4 values:
	user cpu time
	system cpu time
	user gc time
	system gc time

I have looked at the user manual, but it does not explain the precise
meaning of these numbers. Questions:

	1) What is the difference between "user" and "system" cpu time?
	In particular, does user-cpu time include paging? Or is it included
	in "system" cpu? 

	2) Is there any way to get the number of IO's performed for a certain
	interval?

	3) What is the difference between "user" gc and "system" gc?

Finaly, a pointer to a document describing exactly what these numbers mean
would be great.

Thanks,

/Luis

Luis Miguel
Computer Science Division
570 Evans Hall
University of California
Berkeley, Ca. 94720

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