This is roughly correct. Like in the performance case, the hardware configuration is not touched if the new P-state turns out to be the same as the current one. In addition to the two good links Ravan gave, see also here and here. Generally, ways to obtain that information are specific to the processor model or family. Whether or not turbo P-states are supported at all. However, its configuration can be adjusted via sysfs to a great extent.
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The governor “performance” may decide which speed to use within this range. C1 often pstats as Halt is a state where the processor is not executing instructions, but can return to an executing state essentially instantaneously.
What exactly is a P-state? (Pt. 1) | Intel® Software
Email Required, but never shown. There are a host of other factors influencing runtime, such as cache size and speed, interrupts, etc. Maximum P-state the driver is allowed to set in percent of the maximum supported petate level the highest supported turbo P-state.
drivers – Difference between ACPI CPUfreq and Intel P-State – Ask Ubuntu
I’m neglecting the effect of thermal inertia. Some processors allow multiple cores to be in turbo P-states at the same time, but the maximum P-state that can be set for them generally depends on the number of cores running concurrently.
What those hints are depends on which P-state selection algorithm has been applied to intl given policy or to the CPU it corresponds to.
With recent kernels, it is possible to disable it, in some cases, after boot. Stephen Kitt k 24 Number of P-states supported by pstaye processor between 0 and inclusive including both turbo and non-turbo P-states see Turbo P-states Support. Are there any availiable data about how much energy the processor consumes in each p-state? Change the cpufreq driver from intel pstate to acpi Ask Question.
Both are scaled as ijtel P-state increases. That only is supported in some configurations, though for example, if the HWP feature is enabled in the processorthe operation mode of the driver cannot be changedand if it is not supported in the current configuration, writes to this attribute with fail with an appropriate error.
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In truth, a P-state is both a frequency and voltage operating point. This is where voltage scaling comes into play.
C0 is the operating state. All I can suggest, is that you try it.
What exactly is a P-state? (Pt. 1)
Sign up using Email and Password. The maximum supported one-core turbo P-state if turbo P-states are supported. The one-core maximum turbo P-state is thus the maximum supported one overall.
All CPUs are affected by the global limits that is, none of them can be requested to run faster than the global maximum and none of them can be requested to run slower than the global minimum. They represent different energy vs performance hints and should be self-explanatory, except that default represents whatever hint value was set by the platform firmware.
Hi, Please see my earlier blog entries on C-states. I hope to be extending this soon. Sign up or log in Sign up using Google. Post as a guest Name.