Messages in this thread | | | From | Andi Kleen <> | Subject | Re: [-mm patch] x86_64 GTOD: offer scalable vgettimeofday | Date | Thu, 1 Feb 2007 13:01:51 +0100 |
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On Thursday 01 February 2007 12:46, Ingo Molnar wrote: > > * jbohac@suse.cz <jbohac@suse.cz> wrote: > > > Inter-CPU monotonicity can not, however, be guaranteed in a vsyscall, > > so vsyscall is not used by default. [...] > > note that this is not actually the case. My patch below, ontop of -mm, > implements a fully monotonic gettimeofday as an optional vsyscall > feature. > > The 'price' paid for it is lower resolution - but it's still good for > those benchmarking TPC-C runs - and /alot/ simpler. It's also quite a > bit faster than any TSC based vgettimeofday, because it doesnt have to > do an RDTSC (or RDTSCP) instruction nor any approximation of the time.
I believe that should be also a separate clock_gettime() CLOCK_
Global settings for these things are bad. Even if you run TPC-C you don't want your other programs that rely on monotonic time to break.
-Andi
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