Re: Process time accounting problem on two CPU machines. Resolved?

[Rich Payne <rdp talisman alphalinux org>]

Remove the Real Time Clock (RTC) support from the kernel, or get the RTC
Lite patches from your favorite kernel mirros and use that.

--rdp

On Wed, 28 Jun 2000, Lew Randerson wrote:

> 
> Around last October, Lars Hjorth reported a process time accounting problem to
> axp-list. Was that resolved?
> 
> We are running kernel 2.2.16 on several UP2000 Dual Alpha machines and
> are seeing the same problem. i.e. There is no reported cpu usage on the
> second cpu even though we know it is being used. For each process,
> /proc/<pid>/cpu always shows cpu1 with no time. /proc/cpuinfo does
> show 2 active cpus. The machines were deliverd with 2.2.14 and had
> the problem with that kernel also.
> 
> 
>     # /usr/bin/uptime
>     3:48pm up 31 min, 5 users, load average: 4.08, 3.30, 1.93
> 
>     # /bin/grep cpu /proc/stat /proc/{1209,1211}/cpu
>     /proc/stat:cpu 656276 0 97507 3080381
>     /proc/stat:cpu0 656276 0 97507 1163299
>     /proc/stat:cpu1 0 0 0 1917082
>     /proc/1209/cpu:cpu 112750 436
>     /proc/1209/cpu:cpu0 112750 436
>     /proc/1209/cpu:cpu1 0 0
>     /proc/1211/cpu:cpu 104966 410
>     /proc/1211/cpu:cpu0 104966 410
>     /proc/1211/cpu:cpu1 0 0
> 
> Note in /proc/stat the idle time for cpu1 is essentially the same as the
> system uptime. So cpu1 is reporting NO user time. My first pass at the
> Linux source showed nothing glaringly wrong in kernel/sched.c or
> alpha/kernel/smp.c..
> 
> 
> Note: All utilities show CPU1 is not used including xosview and procinfo.
> Reported CPU usage is accurate when the machine is booted with nosmp
> and therefore only one cpu is active.
> 
> Thanks for any info, --Lew
> 
> Lew Randerson
> Computational Plasma Physics Group
> Princeton Plasma Physics Lab, Princeton University
> P.O. Box 451
> Princeton, NJ 08543
> 
> lranderson@pppl.gov
> 1 609 243-3134 (voice)
> 1 609 254-3086 (fax)
> 
> 
> 
> 
> 
> 
> 

-- 
Rich Payne
rpayne@alphalinux.org			www.alphalinux.org