Threads and memory management

[Simon Marlow]

On 27/04/2009 11:29, Bulat Ziganshin wrote:
> Hello Simon,
>
> Monday, April 27, 2009, 2:13:26 PM, you wrote:
>
>> This is a very strange result: the user time should not *decrease*, but
>> rather should stay the same or increase a bit when adding cores.  If
>
> ability to run two threads simultaneous may increase performance in
> some scenarios. one example is consumer+producer threads. with 2
> OS threads all produced data are consumed immediately, so we live
> inside L2 cache. with 1 OS thread produced data overflow the cache
> before threads are switched, making execution much slower

Yes, good point.  Though I'd be surprised if that was happening here.

Cheers,
	Simon