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authorVenki Pallipadi <venkatesh.pallipadi@intel.com>2007-06-20 14:26:24 -0700
committerDave Jones <davej@redhat.com>2007-06-21 12:57:53 -0400
commitea48761519bd40d7a881c587b5f3177664b2987e (patch)
tree76694d9cd379490be903d8a73fa7588ad504197e /drivers/cpufreq/cpufreq.c
parent0af99b13c9f323e658b4f1d69a1ccae7d6f3f80a (diff)
[CPUFREQ] ondemand: fix tickless accounting and software coordination bug
With tickless kernel and software coordination os P-states, ondemand can look at wrong idle statistics. This can happen when ondemand sampling is happening on CPU 0 and due to software coordination sampling also looks at utilization of CPU 1. If CPU 1 is in tickless state at that moment, its idle statistics will not be uptodate and CPU 0 thinks CPU 1 is idle for less amount of time than it actually is. This can be resolved by looking at all the busy times of CPUs, which is accurate, even with tickless, and use that to determine idle time in a round about way (total time - busy time). Thanks to Arjan for originally reporting the ondemand bug on Lenovo T61. Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com> Signed-off-by: Dave Jones <davej@redhat.com>
Diffstat (limited to 'drivers/cpufreq/cpufreq.c')
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