Dual processor action

[RedXVII]

Wow, you mean to say you have a real job? Damn that sounds like fun, youre lucky.

[daydreamer]

well if somebody owns a multicpu machine, why not make a few benchmarks on splitting execution and test run it on one thread vs two threads
and put together some different tests

There is no need to do this, it will just run faster. But not twice as fast. AFAIK even if it is two distinct processors then most of the time they still share the same memory bus - unless it is a very expensive server mobo. And with dual core, both cores share the same cache. But the object of multi-threading is not to *speed* the app up, it is to spread the load. And dual core/processor machines don't run twice as fast, they just have close to twice the horsepower, which is a big difference.

Just to make your mouths water - i am currently working on a large data warehousing and business intelligence project, it runs on a machine that has 8 cpu's - and while processing we max them all out  :eek :8)

drool, now where do I buy such machine with my new paycheck, forget about pay rent & food :)

I understand there is no point in making asm memorycopy faster, because limited to cache/memory anyway, but split execution of heavy calculation on two threads should be faster, but in what cases fastest?, if I have dualcore and start two threads simultanously and they perform math on same data, one thread at even adresses, the other at odd adresses wouldnt that be most efficient vs each thread working on different datablocks, with big difference between them in adress range?

[daydreamer]

well if somebody owns a multicpu machine, why not make a few benchmarks on splitting execution and test run it on one thread vs two threads
and put together some different tests

There is no need to do this, it will just run faster. But not twice as fast. AFAIK even if it is two distinct processors then most of the time they still share the same memory bus - unless it is a very expensive server mobo. And with dual core, both cores share the same cache. But the object of multi-threading is not to *speed* the app up, it is to spread the load. And dual core/processor machines don't run twice as fast, they just have close to twice the horsepower, which is a big difference.

Just to make your mouths water - i am currently working on a large data warehousing and business intelligence project, it runs on a machine that has 8 cpu's - and while processing we max them all out  :eek :8)

look at pentium D test on toms hardware,no faster on games and apps not threadoptimized, 55% faster on 3dmax render because it supports several threads and some programs also benefitted from it

[VlasRad]

good example of when threading give very good speedup: http://board.flatassembler.net/topic.php?t=5122