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RE: Processor Speed on Linux

From: Marquez, Chris <cmarquez_at_collegeboard.org>
Date: Wed, 17 Aug 2005 11:43:48 -0400
Message-ID: <B30C2483766F9342B6AEF108833CC84E05BD5F1C@ecogenemld50.Org.Collegeboard.local>


Paul & Nuno,

Good stuff thanks!

---Easy to see/remember.
[oracle_at_db02 oracle]$ dmesg | grep runq
mapping CPU#0's runqueue to CPU#2's runqueue. mapping CPU#1's runqueue to CPU#3's runqueue.

---Little harder to remember.
[oracle_at_db02 oracle]$ cat /proc/cpuinfo | grep flags

flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm
flags           : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm



-----Original Message-----
From: oracle-l-bounce_at_freelists.org on behalf of Paul Drake Sent: Wed 8/17/2005 9:40 AM
To: dbvision_at_iinet.net.au
Cc: oracle-l_at_freelists.org
Subject: Re: Processor Speed on Linux  

On 8/17/05, Nuno Souto <dbvision_at_iinet.net.au> wrote:
> Marquez, Chris apparently said,on my timestamp of 17/08/2005 2:30 AM:
> > Be careful...with Intel HYPER THREADING two physical CPU is reported and
> > seen as four physical CPU.
> >
>
>
> When you do cat /proc/cpuinfo, check out the flags field.
> If it has the string "ht" in it, it's a hyper thread chip.
>
> --
> Cheers
> Nuno Souto
> in sunny Sydney, Australia
> dbvision_at_iinet.net.au

Also-

check dmesg for mapping of the hyperthreaded cpu onto the runqueue of the physical processor. In top, one can see on a lightly loaded server, processes run on the 2 physical CPUs first (on a RHEL ES kernel - update 5).

Paul

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Received on Wed Aug 17 2005 - 10:47:59 CDT

Original text of this message

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