Timer library

Alex Kiernan alexk at demon.net
Tue Feb 6 09:59:47 UTC 2001


Russ Allbery <rra at stanford.edu> writes:

> Alex Kiernan <alexk at demon.net> writes:
> 
> > OK, but there's profilers for every platform (but the Sun one does have
> > the advantage of not needing a rebuild) - I wasn't so much thinking that
> > the code shouldn't be there, but more that it should be a build
> > option. I guess so long as the added cost when disabled is negligible
> > its not an issue.
> 
> It's negligible when it's enabled, so far as I can tell.

Yeah, I realised my confusion afterwards as I was thinking of the
enabled case.

>  It adds a
> periodic call to gettimeofday, but that's called so frequently by most
> programs that it tends to be pretty efficient (it's implemented as a
> special trap on SPARC, for example, that doesn't go through the normal
> system call channels).
> 

Darn, I knew about gethrtime, but not gettimeofday...

fx: man examines libc...

...OK gettimeoday is a wrapper around gethrtime which then converts
the result from ns into a struct timeval. You live & learn!

-- 
Alex Kiernan, Principal Engineer, Development, Thus PLC


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