[ubuntu-uk] CFLAGS Manipulation in Ubuntu

[Alan Pope]

On 4 May 2010 14:05, Stuart Bird <stuart.bird1 at googlemail.com> wrote:
> Basically I need to ensure that Ubuntu is multiprocessor aware and that it
> is making use of all the processors and/or cores when a program designed to
> use them all is run.
>
> I think that makes sense :)
>

Easiest way to see if your system is mp aware is just run something
like "top" in a terminal. The CPU line shows all CPUs activity
aggregated like this:-

top - 14:09:19 up 83 days,  1:07,  4 users,  load average: 1.87, 1.89, 1.95
Tasks: 895 total,   4 running, 891 sleeping,   0 stopped,   0 zombie
Cpu(s):  0.6% us,  0.5% sy,  0.0% ni, 98.7% id,  0.0% wa,  0.0% hi,  0.0% si
Mem:  131900740k total, 113857192k used, 18043548k free,   133156k buffers
Swap: 33554424k total,        8k used, 33554416k free, 94430544k cached

Press "1" and it will split out each CPU... like this:-

top - 14:09:39 up 83 days,  1:08,  4 users,  load average: 1.77, 1.87, 1.94
Tasks: 895 total,   2 running, 893 sleeping,   0 stopped,   0 zombie
Cpu0  :  0.6% us,  0.3% sy,  0.0% ni, 99.1% id,  0.0% wa,  0.0% hi,  0.0% si
Cpu1  :  3.0% us,  0.6% sy,  0.0% ni, 96.2% id,  0.0% wa,  0.0% hi,  0.0% si
Cpu2  :  5.6% us,  0.3% sy,  0.0% ni, 93.9% id,  0.0% wa,  0.0% hi,  0.1% si
Cpu3  :  2.2% us,  1.6% sy,  0.0% ni, 95.9% id,  0.2% wa,  0.0% hi,  0.0% si
Cpu4  :  0.8% us,  0.3% sy,  0.0% ni, 98.8% id,  0.1% wa,  0.0% hi,  0.0% si
Cpu5  :  1.0% us,  0.3% sy,  0.0% ni, 98.6% id,  0.0% wa,  0.0% hi,  0.0% si
Cpu6  : 10.8% us,  1.6% sy,  0.0% ni, 86.9% id,  0.0% wa,  0.1% hi,  0.6% si
Cpu7  : 29.8% us,  2.0% sy,  0.0% ni, 67.4% id,  0.0% wa,  0.0% hi,  0.7% si
Cpu8  : 36.0% us,  1.5% sy,  0.0% ni, 61.7% id,  0.1% wa,  0.0% hi,  0.8% si
Cpu9  : 12.9% us,  0.6% sy,  0.0% ni, 86.1% id,  0.1% wa,  0.1% hi,  0.3% si
Cpu10 :  0.9% us,  0.3% sy,  0.0% ni, 98.3% id,  0.3% wa,  0.0% hi,  0.1% si
Cpu11 :  4.5% us,  0.5% sy,  0.0% ni, 94.2% id,  0.5% wa,  0.0% hi,  0.3% si
Mem:  131900740k total, 113859240k used, 18041500k free,   133172k buffers
Swap: 33554424k total,        8k used, 33554416k free, 94431560k cached

If you see multiple lines for CPU then chances are you're good to go.

Cheers,
Al.