Date: Fri, 3 Jun 2016 07:28:31 -0700 From: Maxim Sobolev <sobomax@freebsd.org> To: Adrian Chadd <adrian.chadd@gmail.com> Cc: FreeBSD Current <freebsd-current@freebsd.org>, freebsd-threads@freebsd.org, FreeBSD Questions <freebsd-questions@freebsd.org>, "freebsd-arch@freebsd.org" <freebsd-arch@freebsd.org> Subject: Re: CLOCK_MONOTONIC / CLOCK_UPTIME is not really monotonic between threads Message-ID: <CAH7qZftxd=0spJTaAVv2RctXyQmV=cd7JL-xnYnaqfMhoeX7hg@mail.gmail.com> In-Reply-To: <CAJ-VmomA%2BwY1Lo7XS86c91hzeJFbMSGpVamfCpM0roaARHcfqg@mail.gmail.com> References: <CAH7qZfsBLM_wqdTXiiyVvevwU%2Bu257dX9JvZFftfntduUaZDMw@mail.gmail.com> <CAJ-VmomA%2BwY1Lo7XS86c91hzeJFbMSGpVamfCpM0roaARHcfqg@mail.gmail.com>
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a. multiple cores. b. makes no difference c. yes, I believe so kern.timecounter.tsc_shift: 1 kern.timecounter.smp_tsc_adjust: 0 kern.timecounter.smp_tsc: 1 kern.timecounter.invariant_tsc: 1 machdep.tsc_freq: 2658118740 machdep.disable_tsc_calibration: 0 machdep.disable_tsc: 0 d. no, single socket Intel Q6700. I've also seen this problem on core i7-4770 running virtualbox 5.x. I have a hints that this also happens on our bigger production boxes, but I have no specifics yet. On Thu, Jun 2, 2016 at 10:05 PM, Adrian Chadd <adrian.chadd@gmail.com> wrote: > [snip] > > a) is it on one core, or multiple cores? > b) CLOCK_MONOTONIC_FAST? > c) is it on a system that /has/ invariant-TSC ? > d) is this a multi-socket system? > > > > -adrian > >
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