Messages in this thread | | | From | "Langsdorf, Mark" <> | Date | Wed, 30 Sep 2009 09:30:57 -0500 | Subject | RE: [PATCH] Option to synchronize P-states for AMD family 0xf |
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> > AMD Family 0xf processors (Athlon 64s and Opterons) do not > > have P-State or C-State invariant TSCs. Instead, the TSC > > increments at the current processor frequency, which makes > > it unstable and unreliable if cpufreq is enabled. > > > > This patch introduces a new command parameter for the > > PowerNow! driver called "tscsync". When tscsync is > > set to 1, the driver forces all processors in the system > > to change frequency as the same time to the same frequency. > > This unified change means that all the TSCs in the system > > increment at the same rate. > > Cool feature. Does Linux consider the TSC as stable on these machines > even after a longer uptime (say after a week)?
Ask me in a week. Linux time-keeping code has evolved quite a bit since I last looked at this code.
-Mark Langsdorf Operating System Research Center AMD
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