Re: Leaving the Desktop Market

On 12 May 2014 10:35, Allan Jude <freebsd_at_allanjude.com> wrote:
> I have this system:
>
> hw.model: Intel(R) Xeon(R) CPU E3-1220 v3 _at_ 3.10GHz
> hw.ncpu: 4
>
> http://ark.intel.com/products/75052
>
> dev.cpu.0.%desc: ACPI CPU
> dev.cpu.0.%driver: cpu
> dev.cpu.0.%location: handle=\_PR_.CPU0
> dev.cpu.0.%pnpinfo: _HID=none _UID=0
> dev.cpu.0.%parent: acpi0
> dev.cpu.0.freq: 3100
> dev.cpu.0.freq_levels: 3101/80000 3100/80000 2900/72713 2800/69558
> 2600/62669 2400/56794 2300/53935 2100/47673 1900/42370 1800/39795
> 1600/34136 1500/31729 1300/26432 1137/23128 1100/21994 1000/19851
> 875/17369 800/15113 700/13223 600/11334 500/9445 400/7556 300/5667
> 200/3778 100/1889
> dev.cpu.0.cx_supported: C1/1/1 C2/2/148
> dev.cpu.0.cx_lowest: C8
> dev.cpu.0.cx_usage: 9.01% 90.98% last 807us
> dev.cpu.1.%desc: ACPI CPU
> dev.cpu.1.%driver: cpu
> dev.cpu.1.%location: handle=\_PR_.CPU1
> dev.cpu.1.%pnpinfo: _HID=none _UID=0
> dev.cpu.1.%parent: acpi0
> dev.cpu.1.cx_supported: C1/1/1 C2/2/148
> dev.cpu.1.cx_lowest: C8
> dev.cpu.1.cx_usage: 11.70% 88.29% last 21303us
> dev.cpu.2.%desc: ACPI CPU
> dev.cpu.2.%driver: cpu
> dev.cpu.2.%location: handle=\_PR_.CPU2
> dev.cpu.2.%pnpinfo: _HID=none _UID=0
> dev.cpu.2.%parent: acpi0
> dev.cpu.2.cx_supported: C1/1/1 C2/2/148
> dev.cpu.2.cx_lowest: C8
> dev.cpu.2.cx_usage: 15.17% 84.82% last 22987us
> dev.cpu.3.%desc: ACPI CPU
> dev.cpu.3.%driver: cpu
> dev.cpu.3.%location: handle=\_PR_.CPU3
> dev.cpu.3.%pnpinfo: _HID=none _UID=0
> dev.cpu.3.%parent: acpi0
> dev.cpu.3.cx_supported: C1/1/1 C2/2/148
> dev.cpu.3.cx_lowest: C8
> dev.cpu.3.cx_usage: 11.74% 88.25% last 6073us
>

So ACPI is exposing C1 and C2 only.

> According to the Intel specs (Page 11), this processor supports C1, C1E,
> C3, C6 and C7
>
> The above sysctl dump shows only C1 and C2. I wonder if the C2 is
> actually C3
>
> http://www.intel.com/content/dam/www/public/us/en/documents/datasheets/xeon-e3-1200v3-vol-1-datasheet.pdf

It'd say C2/3/xxx in that case.

Chances are you'll end up seeing it fall into deeper sleep states. Try
installing intel-pcm; kldload cpuctl; run pcm.x 1 . See if it's
entering lower CPU states.

> How is our support for the newer Cx States introduced in Haswell, which
> can apparently go as high as C10

I don't know if we get those exposed via ACPI. I know there's a bunch
of cute things we could be doing with MWAIT that we aren't, but we
certainly should be drifting into lower sleep states.

Just run intel-pcm and see.

Thanks,



-a