Messages in this thread |  | | Date | Thu, 1 Feb 2007 20:41:09 +0100 | From | Vojtech Pavlik <> | Subject | Re: [patch 0/9] x86_64: reliable TSC-based gettimeofday |
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On Thu, Feb 01, 2007 at 08:56:48AM -0800, john stultz wrote: > On Thu, 2007-02-01 at 15:52 +0100, Jiri Bohac wrote: > > On Thu, Feb 01, 2007 at 12:20:59PM +0100, Andi Kleen wrote: > >> > > > The big strategic problem is how to marry your patchkit to John Stultz's > > > clocksources work which is also competing for merge. Any thoughts on that? > > > > I'll look into that next week. Sorry, I wanted to do that a long time > > ago, but I spent weeks (over a month) fighting a nasty livelock > > in the code. (Morale: think twice before using a spinlock inside > > a {do .. while (read_seqretry(..))} loop) > > The first step here shouldn't be too difficult. Just create a _read > function that uses your code to return monotonic TSC cycles (instead of > nanoseconds w/ gettimeofday). Then just create a clocksource structure > for it.
guess_mt() is more or less the function you're looking for. (With the exception of the cpufreq and mode switching logic.)
> The harder part will be the vsyscall, as you will need extra per cpu > data in the vsyscall read. I had some test code for this situation > awhile back, so if you get the first part functioning correctly (just a > clocksource w/o a vread pointer), I'll gladly help you get the vsyscall > bits working. > > thanks > -john > >
-- Vojtech Pavlik Director SuSE Labs - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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