Current state of multi-core awareness

[Seann Clark]

Patrick O'Callaghan wrote:
> On Fri, Dec 5, 2008 at 4:41 PM,  <dsavage at peaknet.net> wrote:
>
>   
>> Of the thousands of 64-bit F10 applications/tools/utilities, I wonder how
>> many are aware of and can scale across multiple cores. Has anyone done a
>> recent survey to see which packages are [not] multi-core aware?
>>     
>
> I may be way off-base here, but I would expect very few if any apps
> are "multi-core aware". Multiple cores get you better performance when
> more than one process needs the cpu, but a single I/O-limited process
> isn't going to go any faster. Likewise, single-threaded apps can't do
> anything with multiple cores even if they aren't I/O limited.
> Specialized parallel-programming apps are a different matter, but how
> many of those do we typically see on a desktop?
>
> poc
>
>   
As stated very well above, it depends on the people who developed the 
package as to how it uses a CPU, if it is single threaded (and there are 
a lot of those type out there) then yes, it will plug one core. If it is 
multithreaded, like say Apache, then, under load you will see it peg all 
your CPU's/Cores instead of just one. I see this type of behavior on my 
home server, which has quad core dual Xeon's, and when I stress test 
HTTP all eight cores start to peak as the load gets higher. As for 
anything disk I/o intensive, it can be purposeful to have it hog just 
one core (IE not to build in multi-CPU support) since it improves 
overall system performance on non I/o intensive programs. Anything 
package based will be higher on the I/o, and it would be a bad thing to 
have it hog the entire system processing stuff that has to wait to be 
written to disk. After all, how many irate users do you see, that are 
angry because updates are running and taking forever, and they can't use 
anything else because that package manager is taking forever?


If you want to view what is, and isn't multi-core aware, look at what 
does, and doesn't use SMP, since that has been around since more than 
one 'virtual' CPU has been in use (Hyperthreading) and used with 
multicores.


And on an honest note, I don't really see how package management would 
require more CPU power, when as a database type program, it would 
require faster disks to perform better, not more power from the CPU. 


~Seann
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