topic Kevin, in Software Archive

offload_signaled documentation

jimdempseyatthecove — Thu, 18 Feb 2016 13:30:36 GMT

In the C++ (v16.0 update 1) documentation:

Determining if Code has Completed Running on a Coprocessor

To determine if a section of offloaded code has completed running on a given coprocessor, you can use the API _Offload_signaled().

The syntax for this API is:

extern int _Offload_signaled(int target_number, void *signal);

Nowhere is it described what the return values are.

Same thing in the Fortran documentation

Determining if Code has Completed Running on a Coprocessor

To determine if a section of offloaded code has completed running on a given coprocessor, you can use the API OFFLOAD_SIGNALED().

The syntax for this API is:

OFFLOAD_SIGNALED(target_number,signal)

And you have to look inside mic_lib.f90 to find it returns an integer without specifying what the values can be.

In the mic_lib.f90 we find:

enum, bind(C)
    enumerator :: OFFLOAD_SUCCESS  = 0
    enumerator :: OFFLOAD_DISABLED          ! offload is disabled
    enumerator :: OFFLOAD_UNAVAILABLE       ! card is not available
    enumerator :: OFFLOAD_OUT_OF_MEMORY     ! not enough memory on device
    enumerator :: OFFLOAD_PROCESS_DIED      ! target process has died
    enumerator :: OFFLOAD_ERROR             ! unspecified error
end enum

But it is not stated (clear) as if these are, or are the only return values. If they are the return values, then missing is OFFLOAD_BUSY

Does someone know what the return values are for OFFLOAD_SIGNALED?

Jim Dempsey

I'll confirm, but I

Kevin_D_Intel — Thu, 18 Feb 2016 15:38:00 GMT

I'll confirm, but I understand offload_signaled() returns a 1 (true) or 0 (false) based on the signal having been set (1) or not (0). The values cited from mic_lib.f90 correspond to the STATUS() clause.

Kevin,

jimdempseyatthecove — Thu, 18 Feb 2016 16:59:17 GMT

Kevin,

The results of STATUS() clause are those listed above. My interest is in the return of OFFLOAD_SIGNALED, which has a different (additional) set of return values.

In particular, OFFLOAD_SIGNALED is intended for use with asynchronous offloads. The intended purpose is not only to determine STATUS(), but also if the signaled state is not signaled and the offload associated with the signal has not aborted (IOW running).

Note, status OFFLOAD_UNAVAILABLE is not suitable for SIGNAL_BUSY or SIGNAL_NOT_SIGNALED. Though I could envision a naïve implementation to assume OFFLOAD_UNAVAILABLE is interchangeable.

Jim Dempsey

Jim,

Ravi_N_Intel — Thu, 18 Feb 2016 21:38:50 GMT

Jim,
The return value is 1 (true) or 0 (false) if offload associated with the signal has completed or not.

Ravi