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    SubjectRe: [REDO PATCH v7] perf/x86/amd/power: Add AMD accumulated power reporting mechanism
    On Thu, Jun 16, 2016 at 04:44:20PM -0400, Vince Weaver wrote:
    > On Thu, 16 Jun 2016, Huang Rui wrote:
    >
    > > > 1. In theory this should also work on an amd fam16h model 30h
    > > > processor too, correct? The current code limits things to fam15h
    > > > even though the fam16mod30h has all the proper cpuid flags.
    > > >
    > >
    > > I was told this feature would be supported on fam15h 60h, 70h and
    > > later processors before. Just checked the fam16h model 30h BKDG, yes,
    > > it should be also supported. But I didn't test that platform, if you
    > > confirm it works in your side. We can enable it.
    >
    > I can confirm I get power readings on my fam16hmod30h board once I apply a
    > trivial patch to the driver. I'll send the patch in a separate e-mail.
    >

    OK, thanks.

    > > PTSC's frequency is about 100Mhz, it shouldn't be overflow.
    >
    > That's what I thought. I'm trying to read the value using the /dev/msr
    > interface from userspace and I get weird results.
    >
    > i.e.:
    > Jx: read 62d299b84
    > PTSC MSR: read 72fe92
    >
    > sleep 5ms
    >
    > Jy: read 631b453b9
    > PTSC MSR: read 46b25
    >
    > this happens about half the time (PTSC going backwards). Though
    > admittedly the problem could somehow be in the MSR code I'm using.
    >

    Can you try to read the MSR value two times with the same core
    (rdmsrl_on_cpu)?

    Thanks,
    Rui

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