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Len Brown authored
The CC1 column in tubostat can be computed by subtracting the core c-state residency countes from the total Cx residency. CC1 = (Idle_time_as_measured by MPERF) - (all core C-states with residency counters) However, as the underlying counter reads are not atomic, error can be noticed in this calculations, especially when the numbers are small. Denverton has a hardware CC1 residency counter to improve the accuracy of the cc1 statistic -- use it. At the same time, Denverton has no concept of CC3, PC3, CC7, PC7, so skip collecting and printing those columns. Finally, a note of clarification. Turbostat prints the standard PC2 residency counter, but on Denverton hardware, that actually means PC1E. Turbostat prints the standard PC6 residency counter, but on Denverton hardware, that actually means PC2. At this point, we document that differnce in this commit message, rather than adding a quirk to the software. Signed-off-by:
Len Brown <len.brown@intel.com>
7170a374