Date: Fri, 15 Nov 1996 20:49:01 +1100 From: Bruce Evans <bde@zeta.org.au> To: bde@zeta.org.au, thorpej@nas.nasa.gov Cc: freebsd-bugs@freefall.freebsd.org Subject: Re: misc/2007: /usr/include/sys lacking timer arithmetic functions.. Message-ID: <199611150949.UAA07422@godzilla.zeta.org.au>
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[timeval arithmetic macros in <sys/time.h> >NetBSD added these because there were a zillion places where timeval >arithmetic was implemented in the kernel. Centralizing it reduced >code complexity, which is generally considered a good thing. The kernel just uses functions in FreeBSD and NetBSD-old. >They aren't function calls. Everything is done inline, so there's no >additional cost associated with using the abstraction. There's the extra cost of inlining - potentially busted caches if the inline code is larger than the code to call the function. Code that is duplicated in a zillion places is the worst candidate for inlining because the chance of any one block of inline staying in a cache is smaller. I think timeval arithmetic isn't done often enough for inlining to matter, so using function calls is best because it is simpler. Brucehome | help
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