Intel P state always at max freq when idle

[Bloot]

Hello,

I recently upgraded to a i5-4590 Haswell refresh installed on a Gigabyte Z97P-D3 motherboard, so I activated Intel P state in the kernel. But it always stays at maximum frequency when the system is idle, it only scales down when it's busy which is disconcerting, it behaves the opposite way

My kernel setup

[abduct]

In the kernel try setting the "default CPUFreq governor" to "ondemand" so that the system adjusts the processor for you. The option can be found under "Power management and ACPI options -> CPU Frequency Scaling". Also try using the ACPI P-States option as I've read that the Intel P option has a similar bug in which it maxes out the CPU.

Source: I had a similar problem with a laptop and the processor not enabling turbo-boost or scaling automatically.

[Bloot]

[albright]

[Bloot]

[Yamakuzure]

1. You can only use performance and powersave governors, because the p-state driver does not support any other.
   If you want other governors, you have to use ACPI and replace it using phc-intel (which is a p-state driver, too).
   *but* : phc-intel can not fully power up the cpu. My 2.8 GHz i7 (With turbo up to 3.4 GHz) can not go over 2.6 GHz with phc-intel.
   
2. Therefore I use the intel pstate driver from the kernel.
   
   With performance governor:

   Code:

   ~ # LC_ALL=C cpupower frequency-info analyzing CPU 0:   driver: intel_pstate   CPUs which run at the same hardware frequency: 0   CPUs which need to have their frequency coordinated by software: 0   maximum transition latency: 0.97 ms.   hardware limits: 800 MHz - 3.40 GHz   available cpufreq governors: performance, powersave   current policy: frequency should be within 800 MHz and 3.40 GHz.                   The governor "performance" may decide which speed to use                   within this range.   current CPU frequency is 3.29 GHz (asserted by call to hardware).   boost state support:     Supported: yes     Active: yes

   and with powersave governor, AC unplugged:

   Code:

   ~ # LC_ALL=C cpupower frequency-info analyzing CPU 0:   driver: intel_pstate   CPUs which run at the same hardware frequency: 0   CPUs which need to have their frequency coordinated by software: 0   maximum transition latency: 0.97 ms.   hardware limits: 800 MHz - 3.40 GHz   available cpufreq governors: performance, powersave   current policy: frequency should be within 800 MHz and 3.40 GHz.                   The governor "powersave" may decide which speed to use                   within this range.   current CPU frequency is 605 MHz (asserted by call to hardware).   boost state support:     Supported: yes     Active: yes

   
   (Interestingly the tool says that minimum frequency is 800MHz, but it was scaled down to 600MHz. ... conky reports the same, by the way...)
   
3. There seems to be something else wrong with your config if you can not use INTEL_IDLE. Or maybe it's the cpu?
   Here is my config for reference:

   Code:

   /usr/src/linux # grep -P "^[^#].*(FREQ|IDLE|PSTATE)" .config CONFIG_NO_HZ_IDLE=y CONFIG_GENERIC_SMP_IDLE_THREAD=y CONFIG_CPU_FREQ=y CONFIG_CPU_FREQ_GOV_COMMON=y CONFIG_CPU_FREQ_STAT=m CONFIG_CPU_FREQ_STAT_DETAILS=y CONFIG_CPU_FREQ_DEFAULT_GOV_PERFORMANCE=y CONFIG_CPU_FREQ_GOV_PERFORMANCE=y CONFIG_CPU_FREQ_GOV_POWERSAVE=y CONFIG_CPU_FREQ_GOV_USERSPACE=y CONFIG_CPU_FREQ_GOV_ONDEMAND=y CONFIG_CPU_FREQ_GOV_CONSERVATIVE=y CONFIG_X86_INTEL_PSTATE=y CONFIG_X86_ACPI_CPUFREQ=m CONFIG_CPU_IDLE=y CONFIG_CPU_IDLE_GOV_LADDER=y CONFIG_CPU_IDLE_GOV_MENU=y CONFIG_INTEL_IDLE=y

   and this is what idle-info comes up with:

   Code:

   ~ # LC_ALL=C cpupower idle-info CPUidle driver: intel_idle CPUidle governor: menu Analyzing CPU 0: Number of idle states: 6 Available idle states: POLL C1-HSW C1E-HSW C3-HSW C6-HSW C7s-HSW POLL: Flags/Description: CPUIDLE CORE POLL IDLE Latency: 0 Usage: 20346 Duration: 20113894 C1-HSW: Flags/Description: MWAIT 0x00 Latency: 2 Usage: 7175620 Duration: 2884307784 C1E-HSW: Flags/Description: MWAIT 0x01 Latency: 10 Usage: 2076175 Duration: 1951980913 C3-HSW: Flags/Description: MWAIT 0x10 Latency: 33 Usage: 3480621 Duration: 2181767439 C6-HSW: Flags/Description: MWAIT 0x20 Latency: 133 Usage: 1282988 Duration: 980550922 C7s-HSW: Flags/Description: MWAIT 0x32 Latency: 166 Usage: 23154988 Duration: 73947612700

I hope it helps.
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[Bloot]

Thanks Yamakuzure, unfortunately when using you config my cpu never goes down 3.7GHz when idle hence the powersave doesn't work at all even if I adjust it manually.

[albright]

Here is my config

[Ant P.]

Intel cheats, basically. The newer chips use C-states alone for power saving - C2 and higher is effectively 0MHz, though you can't tell that from cpufreq numbers alone.

[Bloot]

It seems Intel P-States is broken for haswell refresh chips https://bugzilla.kernel.org/show_bug.cgi?id=93521

So must wait for next kernel sources and see if it has been adressed.

[Bloot]

4.0.5 kernel finally solved it.

Edit

False alarm... once ati-drivers got compiled against the new kernel, the problem is there again, so I guess it's ati-drivers who prevents the cpu being idle.

[Yamakuzure]

[s4e8]

There's NO freq at idle (C-state), all C3/C6/C7 states stop core-clock, C1 will running at low-speed if C1E enable, or high speed if C1E disable. The reported idle freq is useless.

[Bloot]

[s4e8]

new intel_idle, export both C1 and C1E states, let the cpuidle gorvenor choose which one to use. ACPI idle driver always combine C1 and C1E, and auto-promotion to C1E if BIOS enable it. Unless cpu wont enter deeper C3 or C6 states, there's NO problem if idle governor prefer to C1 instead C1E.

[Bloot]

[Yamakuzure]

@Bloot: I meant "sys-power/powertop", not "top".

But as you are on a desktop computer without battery, it wouldn't help that much anyway. I guess you are right, and your desktop hardware simply isn't able to do it like you want. I always assumed you were on a laptop.

However, my laptop came shipped with an ATI card, but both the open source and proprietary drivers gave me too much trouble. I had it replaced by an nvidia card and am happy now. So if you are right, and it is a driver issue with the proprietary ATI-Drivers, I can at least be sure that my decision was a good one.

For completenes' sake:

Output with AC connected on my laptop:

[yaclo]

same problem here and it's a desktop it's first generation haswell cpu i7 4770 / r9 290

with radeonsi cpu frequency scaling works fine
but with fglrx cpu freq goes to max no matter what

fglrx prevents the cpu being idle