A member of a _Cilk_shared class can not access on MIC

[shuai_z_]

Hi,

Recently, I use _Cilk_shared and _Cilk_offload to offload my c++ code to MIC. The problem is I want to offload a class B, but a member of class B is an object of class A. When I offload class B, the object of class A can not access inside the offload function. So I want to know if there a way to solve this situation? The code is like this:

#include <iostream>
#pragma offload_attribute (push, _Cilk_shared)
#include <offload.h>
#pragma offload_attribute (pop)

class _Cilk_shared A{
    int* buffer;
    int size;
    public:
    A(int size_)
    {
        size = size_;
        buffer = new int[size];
    }
    _Cilk_shared void print()
    {
        int sum = 0;
        for(int i=0;i<size;i++)
           sum+=buffer;
        std::cout<<"size = "<<size<<"sum = "<<sum<<std::endl;
        #ifdef __MIC__
        std::cout<<"ON MIC"<<std::endl;
        #else
        std::cout<<"fail!"<<std::endl;
        #endif
    }
};

class _Cilk_shared B{
    public:
    A data;
    int size;
    const static int DefaultSize = 1<<10;

    B(int size_ = DefaultSize)
    : data(size_)
    , size(size_)
    {}
};

_Cilk_shared B * _Cilk_shared ii;

_Cilk_shared void offload()
{
    ii->data.print();
}

int main()
{
    ii = new (_Offload_shared_malloc(sizeof(B))) _Cilk_shared B();
    _Cilk_offload offload();
}

The result of This code is here:

CARD--ERROR:1 thread:3 myoiPageFaultHandler: 0x1274040 Out of Range!
CARD--ERROR:1 thread:3 _myoiPageFaultHandler: 0x1274040 switch to default signal handle.
CARD--ERROR:1 thread:3 Segment Fault - will exit!
HOST--ERROR: thread:1 myoiScifGetRecvId: Call recv() Header Failed ! for source: 1, errno = 104
HOST--ERROR: thread:2 myoiScifSend: Call send() Failed! errno = 104
HOST--ERROR: thread:2 myoiSend: Failed to send message!
HOST--ERROR: thread:2 _myoiWatchdogDaemon: could not send to target: 1
offload error: process on the device 0 unexpectedly exited with code 1

Thank you for your time!

[Kevin_D_Intel]

I tried a few things without success myself so let me inquire with our Developers about this and get back with your shortly.

[Kevin_D_Intel · Accepted solution]

I identified a change that leads to successful execution and our Developers confirmed it is the correct change noting that this change is needed because "you cannot allocate non-shared memory and assign to shared objects and access them."

The change needed is at line 13. Change it from this:

buffer = new int[size];

to this:

buffer = (_Cilk_shared int *)_Offload_shared_malloc(size);

[shuai_z_]

Thank you! I has modified my code and it works!

[Kevin_D_Intel]

You're welcome. Glad to hear that.