Messages in this thread |  | | | Date | Tue, 17 Dec 2002 11:37:04 -0800 (PST) | | From | Linus Torvalds <> | | Subject | Re: Intel P6 vs P7 system call performance |
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On Tue, 17 Dec 2002, H. Peter Anvin wrote: > > Let's see... it works fine on UP and on *most* SMP, and on the ones > where it doesn't work you just fill in a system call into the vsyscall > slot. It just means that gettimeofday() needs a different vsyscall slot.
The thing is, gettimeofday() isn't _that_ special. It's just not worth a vsyscall of it's own, I feel. Where do you stop? Do we do getpid() too? Just because we can?
This is especially true since the people who _really_ might care about gettimeofday() are exactly the people who wouldn't be able to use the fast user-space-only version.
How much do you think gettimeofday() really matters on a desktop? Sure, X apps do gettimeofday() calls, but they do a whole lot more of _other_ calls, and gettimeofday() is really far far down in the noise for them. The people who really call for gettimeofday() as a performance thing seem to be database people who want it as a timestamp. But those are the same people who also want NUMA machines which don't necessarily have synchronized clocks.
Linus
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