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Date:      Fri, 27 Dec 2002 16:28:52 +0100
From:      Hubert Tournier <hubert.tournier@online.fr>
To:        David Malone <dwmalone@FreeBSD.org>
Cc:        freebsd-bugs@FreeBSD.org
Subject:   Re: i386/46222: CPU speed incorrectly reported
Message-ID:  <3E0C71B4.3000003@online.fr>
In-Reply-To: <200212231100.gBNB0X3R071069@freefall.freebsd.org>
References:  <200212231100.gBNB0X3R071069@freefall.freebsd.org>

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 >Synopsis: CPU speed incorrectly reported
 >State-Changed-From-To: open->feedback
 >State-Changed-By: dwmalone
 >State-Changed-When: Mon Dec 23 02:57:24 PST 2002
 >http://www.freebsd.org/cgi/query-pr.cgi?pr=46222

Hello David and thanks for your answer !

 >The speed of the CPU is actually measured by seeing how many
 >instructions are executed in an interval measured by the real time
 >timer. This suggests that either your CPU is running slow or the
 >timer is running fast.
 >The CPU could be running slow because of APM or ACPI settings
 >reducing power consumption by slowing the CPU. Can you look into
 >this possibility?

After modifying the hardware BIOS setup from
"Battery Save Mode = Low Power" to "Full Power"
instead of getting :

	Timecounter "TSC"  frequency 184530035 Hz
	CPU: Pentium II/Pentium II Xeon/Celeron (184.53-MHz 686-class CPU)

I get the correct answer:

	Timecounter "TSC"  frequency 366597251 Hz
	CPU: Pentium II/Pentium II Xeon/Celeron (366.60-MHz 686-class CPU)

The strange things are:

1) that I'm not running on battery but on AC power so (if I understand
    correctly) this setting should not be relevant
2) that with the same hardware settings (if my memory doesn't play tricks
    on me), the FreeBSD 4.7-RELEASE previously installed on this machine
    reported the correct speed

Perhaps the ACPI code doesn't detect that the laptop is running on AC
power ?

In either BIOS settings, after booting sysctl said and now says that the
machine is running at full speed :

	hw.acpi.cpu.max_speed: 8
	hw.acpi.cpu.current_speed: 8
	hw.acpi.cpu.performance_speed: 8
	hw.acpi.cpu.economy_speed: 4

But it the first case, perhaps it was at full half-speed :-)

PS: I'm not running the APM daemon and my kernel does not include
     "device apm".

Have a nice day !



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