5.2-CURRENT doesn't throttle processor any more

Kevin Oberman oberman at es.net
Thu Jan 8 16:29:06 PST 2004


> Date: Thu, 8 Jan 2004 15:02:42 -0800 (PST)
> From: Jeffrey Katcher <jmkatcher at yahoo.com>
> Sender: owner-freebsd-mobile at freebsd.org
> 
> I cvsup'd this morning and now it seems like the processor is stuck in high
> gear (hw.acpi.cpu.throttle_state=8) regardless of AC state.  Pulling the plug
> gets me:
>    acpi_cpu0: Performance states changed
> Previous it would print that it was switching to another mode
> 
> The system is an IBM T40.  

Yes, but it was lying to you. The system really was not throttling. The
bug has been located, but the default configuration is now to always run
at 100%. There is a new entry for /etc/rc.conf for this, but I'm not
sure that Nate has connected them, yet.

You can manually set this to 50% with 'sysctl hw.acpi.cpu.throttle_state=4'.
Return it to 100% with 'sysctl hw.acpi.cpu.throttle_state=8'.

You might try editing rc.conf to see if this does anything. Also, try
'sysctl hw.acpi.cpu' and see if cx_lowest is set to. It should be 0 for
AC and 2 for battery. This will also impact battery life at the expense
of poorer performance, but not by slowing the CPU. It just takes longer
to restart from when the system is idle.
-- 
R. Kevin Oberman, Network Engineer
Energy Sciences Network (ESnet)
Ernest O. Lawrence Berkeley National Laboratory (Berkeley Lab)
E-mail: oberman at es.net			Phone: +1 510 486-8634


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