Messages in this thread | | | Date | Tue, 23 Sep 2008 14:02:08 -0700 | From | "Martin Bligh" <> | Subject | Re: Unified tracing buffer |
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>> I think the tolerance is about 500 cycles. If that's not sufficient, I guess >> we'll have to either live with some slight misordering (which people have >> pointed out is kind of inevitable anyway) on these broken machines? >> It was sufficient for what we were using it for, but maybe not for everyone. > > Well, I dont care about the trace reordering at all. I care about user > space visible time going backwards issues observed via the > gettimeofday vsyscall. 500 cycles should be fine, I doubt that we can > migrate in less than that :)
Right, that's what we were interested in.
> I guess you try this only for machines where the TSC runs with > constant frequency, right ?
We don't do DVFS on the 'broken' TSC machines, just halt. But yes, it's selective
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