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authorThomas Renninger <trenn@suse.de>2009-04-22 13:48:29 +0200
committerDave Jones <davej@redhat.com>2009-06-15 11:49:41 -0400
commitcef9615a853ebc4972084f7e70b52892557420ac (patch)
tree9578c3371f57ab16be61e18aec307b450106106b /drivers/video/omap
parent45e3e1935e2857c54783291107d33323b3ef33c8 (diff)
[CPUFREQ] ondemand: Uncouple minimal sampling rate from HZ in NO_HZ case
With this patch you have following minimal sampling rate restrictions: Kernel restrictions: If CONFIG_NO_HZ is set, the limit is 10ms fixed. If CONFIG_NO_HZ is not set or no_hz=off boot parameter is used, the limits depend on the CONFIG_HZ option: HZ=1000: min=20000us (20ms) HZ=250: min=80000us (80ms) HZ=100: min=200000us (200ms) HW restrictions: Do not sample/poll more often than HW latency * 100 exported by the low level cpufreq HW driver The higher value of above restrictions is the minimal sampling rate that can be set (and can be seen via ondemand/sampling_rate_min sysfs file) Default sampling rate still is HW latency * 1000, but this will now end up in lower values on latest (Intel and AMD) hardware as these can switch really fast and sampling rate mostly was limited to the 80ms or 200ms (depending on whether HZ=250 or HZ=1000 is used). Signed-off-by: Thomas Renninger <trenn@suse.de> Cc: Pallipadi Venkatesh <venkatesh.pallipadi@intel.com> Signed-off-by: Dave Jones <davej@redhat.com>
Diffstat (limited to 'drivers/video/omap')
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