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Date:      Wed, 25 Jul 2007 15:36:11 -0700 (PDT)
From:      youshi10@u.washington.edu
To:        "V.I.Victor" <idmc_vivr@intgdev.com>
Cc:        freebsd-questions@freebsd.org
Subject:   Re: ACPI slowing CPU... or something else
Message-ID:  <Pine.LNX.4.43.0707251536110.11229@hymn03.u.washington.edu>
In-Reply-To: <W948422073655691185395478@webmail28>

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On Wed, 25 Jul 2007, V.I.Victor wrote:

> On Wed, 25 Jul 2007, Garrett Cooper wrote:
>
>> V.I.Victor wrote:
>>>  I've two 5.4 desktop boxes.  Pretty much the same installation; both
>>>  from the same CD, same apps, no monitor/keyboard, 1-user logged-on via
>>>  ssh (command-line only w/no gui) and otherwise lightly loaded.
>>>
>>>  Box_A: CPU: AMD-K7(tm) Processor (598.84-MHz 686-class CPU)
>>>         avail memory = 121630720 (115 MB)
>>>         ACPI disabled by blacklist.
>>>
>>>  Box_B: CPU: Intel(R) Pentium(R) 4 CPU 1.80GHz (1794.19-MHz 686-class CPU)
>>>         avail memory = 252186624 (240 MB)
>>>         cpu0: <ACPI CPU> on acpi0
>>>         acpi_throttle0: <ACPI CPU Throttling> on cpu0
>>> ...
>
>> Yes. On my virtual machine with ACPI:
>>
>> dev.cpu.0.freq: 2653
>> dev.cpu.0.freq_levels: 2653/-1 2321/-1 1989/-1 1658/-1 1326/-1 994/-1 663/-1
>> 331/-1
>>
>> [root@optimus-vm-7 ~]# dmesg | grep 26
>> FreeBSD 7.0-CURRENT #5: Tue Jul 17 08:22:26 UTC 2007
>> CPU: Intel(R) Core(TM)2 CPU          6700  @ 2.66GHz (2666.79-MHz K8-class
>> CPU)
>> Timecounter "TSC" frequency 2666794890 Hz quality 800
>>
>> What are the following sysctls set to?
>>
>> kern.clockrate
>> hw.acpi.cpu.cx_lowest
>> dev.cpu.0.cx_lowest
>> dev.cpu.0.cx_usage
>
> Thanks for the reply!  I don't seem to have the last 2 you've asked about.
>
> 'sysctl -a | egrep "clockrate|cpu"' reported the following:
>
> kern.clockrate: { hz = 100, tick = 10000, profhz = 1024, stathz = 128 }
> kern.threads.virtual_cpu: 1
> kern.ccpu: 1948
> kern.smp.maxcpus: 1
> kern.smp.cpus: 1
> hw.ncpu: 1
> hw.clockrate: 1794
> hw.acpi.cpu.cx_supported: C1/0
> hw.acpi.cpu.cx_lowest: C1
> hw.acpi.cpu.cx_usage: 100.00%
> machdep.cpu_idle_hlt: 1
> 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: 1796
> dev.cpu.0.freq_levels: 1796/-1 1571/-1 1347/-1 1122/-1 898/-1 673/-1 449/-1 224/-1
> dev.acpi_throttle.0.%parent: cpu0
> dev.cpufreq.0.%driver: cpufreq
> dev.cpufreq.0.%parent: cpu0

Do you have SMP enabled? If so, please realize that you won't benefit from it at all because the chip you have (Willamette) doesn't support SMP (Hyperthreading or multi-core processing). In fact this may hinder your processing a bit, because I believe that adding SMP adds more complicated algorithms and additional job constraints to the kernel scheduler; I could be incorrect though.

You also might be able to tune the kernel clock rate to obtain better performance; I forget what the values were for sysctl, but if you search around the current@ archives a bit, there was a discussion involving VMware and clock tuning approximately 2-3 months ago which details this issue, and possible solutions.

-Garrett




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