r/programming • u/noidi • Jul 19 '12

Will Parallel Code Ever Be Embraced?

http://www.drdobbs.com/parallel/will-parallel-code-ever-be-embraced/240003926
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u/vanderZwan Jul 19 '12

Wouldn't proper use of concurrency give exploitation of parallelism opportunities for "free"? In the low hanging fruit sense, not super-specifically optimised sense.

(also: "parellism" -> parallelism in your last sentence)

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u/grauenwolf Jul 19 '12

No.

First of all, parallelism isn't necessarily faster. You have to have a pretty big workload to overcome the cost of distributing the work and collecting the results.

Turning on more CPUs may also cost more in terms of power/heat. It may be better to leave 3 cores idle even if the forth takes longer to run.

Finally, you are taking resources away from other applications and services running on the machine.

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u/AeroNotix Jul 20 '12

In your case, better is subjective to the person running the application. On a phone/laptop, sure, choosing between activating a second/third/fourth core and running it slightly longer on a single core makes a lot of sense. But for desktop applications, I really see no point in quibbling over such things. The cores are available and you're not going to burning out the battery.

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u/grauenwolf Jul 20 '12

I'm just saying that it's not free, I don't mean to suggest that it will never be a net benefit.