Ian Smith
2015-May-23 15:57 UTC
CPU frequency doesn't drop below 1200MHz (like it used to)
On Sat, 23 May 2015 17:40:26 +0300, Kimmo Paasiala wrote:
> On Sat, May 23, 2015 at 5:15 PM, Ian Smith <smithi at nimnet.asn.au>
wrote:
[..]
> > > It's an Intel Atom running amd64 version of FreeBSD
stable/10:
> > >
> > > FreeBSD firewall.rdnzl.info 10.1-STABLE FreeBSD 10.1-STABLE #1
> > > r283292: Sat May 23 01:08:03 EEST 2015
> > > root at firewall.rdnzl.info:/usr/obj/usr/src/sys/GENERIC amd64
> > >
> > > CPU: Intel(R) Atom(TM) CPU D510 @ 1.66GHz (1666.68-MHz
K8-class CPU)
> > > Origin="GenuineIntel" Id=0x106ca Family=0x6
Model=0x1c Stepping=10
> > >
Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE>
> > >
Features2=0x40e31d<SSE3,DTES64,MON,DS_CPL,TM2,SSSE3,CX16,xTPR,PDCM,MOVBE>
> > > AMD Features=0x20100800<SYSCALL,NX,LM>
> > > AMD Features2=0x1<LAHF>
> > > TSC: P-state invariant, performance statistics
> > >
> > > Powerd was working on 10.1-RELEASE but stopped working after
upgrade
> > > to 10-STABLE and nothing was changed in BIOS settings.
[..]
> > > However, reading the other replies to this thread I get the
impression
> > > that powerd(8) doesn't actually save energy on this
platform and I'm
> > > better off without it?
> >
> > No, I don't think that's correct; using deeper C-states is
most likely a
> > bigger win, but higher than needed CPU freq will still use extra
power,
> > so run hotter. `sysctl dev.cpu` will also reveal your C-state usage.
> >
> > Reason I'm pursuing this is that this change shouldn't hurt,
but it will
> > flush out those cases where people were only getting cpufreq due to
use
> > of a 'relative' cpufreq driver like p4tcc, unless EST's
enabled in BIOS;
> > I suspect yours may be one such case :) If not, there's a bug to
fix.
Seems _I've_ got a bug to fix; I need to stop assuming all modern Intel
CPUs are going to make SpeedStep and/or deeper C-states available :(
> Looking deeper into this it appears I don't have speedstep (EST)
> support in the CPU it being a crappy Atom D510:
>
> http://ark.intel.com/products/43098
Indeed. It is rated at only 13W TDP, so relatively low power anyway.
> This the full 'sysctl dev.cpu' output:
>
> % sysctl dev.cpu
> dev.cpu.3.cx_usage: 100.00% last 65712us
> dev.cpu.3.cx_lowest: C1
> dev.cpu.3.cx_supported: C1/1/0
[..]
> dev.cpu.0.cx_usage: 100.00% last 3132us
> dev.cpu.0.cx_lowest: C1
> dev.cpu.0.cx_supported: C1/1/0
> dev.cpu.0.%parent: acpi0
> dev.cpu.0.%pnpinfo: _HID=none _UID=0
> dev.cpu.0.%location: handle=\_PR_.P001
> dev.cpu.0.%driver: cpu
> dev.cpu.0.%desc: ACPI CPU
> dev.cpu.%parent:
It doesn't even provide dev.cpu.0.freq, and has no deeper C-states
('Idle States' on that page) available, so it looks like you may as well
not bother running powerd. Others maybe can offer better suggestions.
> So I should keep those two hints in loader.conf to use p4tcc I guess?
If this is a desktop I'd just let it run flat out, ie disable p4tcc and
acpi_throttle, have no cpufreq and forget powerd.
If it's a laptop and power consumption on battery matters to you, you
could see if p4tcc's lower frequencies actually save any power much, by
running 'powerd -v' in a terminal while testing with different loads, or
if your 'acpiconf -i0' shows discharging rates in mA or mW, or both.
Sorry again for my poor assumption, and thanks for the data point!
cheers, Ian
Kimmo Paasiala
2015-May-23 17:08 UTC
CPU frequency doesn't drop below 1200MHz (like it used to)
On Sat, May 23, 2015 at 6:57 PM, Ian Smith <smithi at nimnet.asn.au> wrote:> On Sat, 23 May 2015 17:40:26 +0300, Kimmo Paasiala wrote: > > On Sat, May 23, 2015 at 5:15 PM, Ian Smith <smithi at nimnet.asn.au> wrote: > [..] > > > > It's an Intel Atom running amd64 version of FreeBSD stable/10: > > > > > > > > FreeBSD firewall.rdnzl.info 10.1-STABLE FreeBSD 10.1-STABLE #1 > > > > r283292: Sat May 23 01:08:03 EEST 2015 > > > > root at firewall.rdnzl.info:/usr/obj/usr/src/sys/GENERIC amd64 > > > > > > > > CPU: Intel(R) Atom(TM) CPU D510 @ 1.66GHz (1666.68-MHz K8-class CPU) > > > > Origin="GenuineIntel" Id=0x106ca Family=0x6 Model=0x1c Stepping=10 > > > > Features=0xbfebfbff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,APIC,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,CLFLUSH,DTS,ACPI,MMX,FXSR,SSE,SSE2,SS,HTT,TM,PBE> > > > > Features2=0x40e31d<SSE3,DTES64,MON,DS_CPL,TM2,SSSE3,CX16,xTPR,PDCM,MOVBE> > > > > AMD Features=0x20100800<SYSCALL,NX,LM> > > > > AMD Features2=0x1<LAHF> > > > > TSC: P-state invariant, performance statistics > > > > > > > > Powerd was working on 10.1-RELEASE but stopped working after upgrade > > > > to 10-STABLE and nothing was changed in BIOS settings. > [..] > > > > However, reading the other replies to this thread I get the impression > > > > that powerd(8) doesn't actually save energy on this platform and I'm > > > > better off without it? > > > > > > No, I don't think that's correct; using deeper C-states is most likely a > > > bigger win, but higher than needed CPU freq will still use extra power, > > > so run hotter. `sysctl dev.cpu` will also reveal your C-state usage. > > > > > > Reason I'm pursuing this is that this change shouldn't hurt, but it will > > > flush out those cases where people were only getting cpufreq due to use > > > of a 'relative' cpufreq driver like p4tcc, unless EST's enabled in BIOS; > > > I suspect yours may be one such case :) If not, there's a bug to fix. > > Seems _I've_ got a bug to fix; I need to stop assuming all modern Intel > CPUs are going to make SpeedStep and/or deeper C-states available :( > > > Looking deeper into this it appears I don't have speedstep (EST) > > support in the CPU it being a crappy Atom D510: > > > > http://ark.intel.com/products/43098 > > Indeed. It is rated at only 13W TDP, so relatively low power anyway. > > > This the full 'sysctl dev.cpu' output: > > > > % sysctl dev.cpu > > > dev.cpu.3.cx_usage: 100.00% last 65712us > > dev.cpu.3.cx_lowest: C1 > > dev.cpu.3.cx_supported: C1/1/0 > [..] > > dev.cpu.0.cx_usage: 100.00% last 3132us > > dev.cpu.0.cx_lowest: C1 > > dev.cpu.0.cx_supported: C1/1/0 > > dev.cpu.0.%parent: acpi0 > > dev.cpu.0.%pnpinfo: _HID=none _UID=0 > > dev.cpu.0.%location: handle=\_PR_.P001 > > dev.cpu.0.%driver: cpu > > dev.cpu.0.%desc: ACPI CPU > > dev.cpu.%parent: > > It doesn't even provide dev.cpu.0.freq, and has no deeper C-states > ('Idle States' on that page) available, so it looks like you may as well > not bother running powerd. Others maybe can offer better suggestions. > > > So I should keep those two hints in loader.conf to use p4tcc I guess? > > If this is a desktop I'd just let it run flat out, ie disable p4tcc and > acpi_throttle, have no cpufreq and forget powerd. > > If it's a laptop and power consumption on battery matters to you, you > could see if p4tcc's lower frequencies actually save any power much, by > running 'powerd -v' in a terminal while testing with different loads, or > if your 'acpiconf -i0' shows discharging rates in mA or mW, or both. > > Sorry again for my poor assumption, and thanks for the data point! > > cheers, IanIt's a firewall/router with some minimal services like nginx running. I'll just leave it like it's now without any frequency control. Thanks, -Kimmo