linux-kernel - Re: CPU off-on-off: lost CPU management?

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Date:	Wed, 6 Jun 2007 13:50:20 +0200
From:	"Peter Oruba" <peter.oruba@....com>
To:	"Mircea Bardac" <dev.list@...cea.bardac.net>
cc:	stefan.prechtel@...glemail.com,
	"Linux List" <linux-kernel@...r.kernel.org>
Subject: Re: CPU off-on-off: lost CPU management?

I'm sorry, I am not able to reproduce this issue (using 2.6.21.3). Everything 
works fine on my Turion laptop. It looks like there is also CPU hotplug 
involved in that issue, since brining cpu1 back on doesn't update siblings 
and cpu_cores in /proc/cpuinfo as well. Can you specify more details about 
the system you are using? Have you tried enabling CONFIG_CPU_FREQ_DEBUG and 
booting with "cpufreq.debug=7"?

Peter Oruba


Am Dienstag, 5. Juni 2007 11:56:44 schrieb Mircea Bardac:
> On Tuesday 05 June 2007 12:52:59 Mircea Bardac wrote:
> > Hi Peter,
> >
> > This time with Kernel 2.6.21.3.
> >
> > [...]
> >
> > # echo 1 > /sys/devices/system/cpu/cpu1/online
> >
> > # cat /proc/cpuinfo
> > processor       : 0
> > vendor_id       : AuthenticAMD
> > cpu family      : 15
> > model           : 72
> > model name      : AMD Turion(tm) 64 X2 Mobile Technology TL-52
> > stepping        : 2
> > cpu MHz         : 800.000
> > cache size      : 512 KB
> > physical id     : 0
> > siblings        : 1
> > core id         : 0
> > cpu cores       : 1
> > fdiv_bug        : no
> > hlt_bug         : no
> > f00f_bug        : no
> > coma_bug        : no
> > fpu             : yes
> > fpu_exception   : yes
> > cpuid level     : 1
> > wp              : yes
> > flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
> > mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext
> > fxsr_opt rdtscp lm 3dnowext 3dnow pni cx16 lahf_lm cmp_legacy svm extapic
> > cr8legacy ts fid vid ttp tm stc
> > bogomips        : 1597.67
> > clflush size    : 64
> >
> > processor       : 1
> > vendor_id       : AuthenticAMD
> > cpu family      : 15
> > model           : 72
> > model name      : AMD Turion(tm) 64 X2 Mobile Technology TL-52
> > stepping        : 2
> > cpu MHz         : 798.015
> > fdiv_bug        : no
> > hlt_bug         : no
> > f00f_bug        : no
> > coma_bug        : no
> > fpu             : yes
> > fpu_exception   : yes
> > cpuid level     : 1
> > wp              : yes
> > flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge
> > mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext
> > fxsr_opt rdtscp lm 3dnowext 3dnow pni cx16 lahf_lm cmp_legacy svm extapic
> > cr8legacy ts fid vid ttp tm stc
> > bogomips        : 1596.26
> > clflush size    : 64
>
> As a follow-up:
>
> As Stefan noticed initially, the CPU frequency of the 2nd CPU is different
> after the CPU is brought back online.
>
> Mircea


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