TBB 3. update 5.0 question

[michaelnikelsky1]

Hi,

I just read the changes of the update 5.0 and happily stumbled upon this:

-Added automatic propagation of master thread FPU settings to TBB worker threads.

What I wonder is: Does this also set the SSE control registers? At the moment I have to do something like

const unsigned int oldState = _mm_getcsr();
_mm_setcsr( oldState | 0x8040);

....do work

_mm_setcsr( oldState);

each time I enter the operator() function of my task since this isnt propagated. Will this be done automatically when I do it in the master thread with the 5.0 update?

Michael

[Andrey_Marochko]

Yes, MXCSR is propagated too.

The only caveat is that the snapshot of FPU settings is done at the moment of task scheduler initialization in a master thread (e.g. when task_scheduler_init object is created). Thus if you change them afterwards, the current values will remain unknown to worker threads.

On the other hand if you uninitialize TBB scheduler (destroy task_scheduler_init object), change FPU settings, and then initialize the scheduler again, the new setting will be visible to workers.

[michaelnikelsky1]

Great news, thanks :)