On Fri, Aug 21, 2015 at 12:45:50AM -0700, tip-bot for Vitaly Kuznetsov wrote: > Commit-ID: 88c9281a9fba67636ab26c1fd6afbc78a632374f > Gitweb: http://git.kernel.org/tip/88c9281a9fba67636ab26c1fd6afbc78a632374f > Author: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx> > AuthorDate: Wed, 19 Aug 2015 09:54:24 -0700 > Committer: Ingo Molnar <mingo@xxxxxxxxxx> > CommitDate: Fri, 21 Aug 2015 08:44:38 +0200 > > x86/hyperv: Mark the Hyper-V TSC as unstable > > The Hyper-V top-level functional specification states, that > "algorithms should be resilient to sudden jumps forward or > backward in the TSC value", this means that we should consider > TSC as unstable. In some cases tsc tests are able to detect the > instability, it was detected in 543 out of 646 boots in my > testing: > > Measured 6277 cycles TSC warp between CPUs, turning off TSC clock. > tsc: Marking TSC unstable due to check_tsc_sync_source failed > > This is, however, just a heuristic. On Hyper-V platform there > are two good clocksources: MSR-based hyperv_clocksource and > recently introduced TSC page. *groan*.. and where are the paravirt ops like pv_time_ops for hyperv to fix up this mess? -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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