Using L1/L2 cache as a scratchpad memory

Dear all,

Explicitly cache control is a one of important feature in Xeonphi (MIC). How could I use the L1 or L2 as scratchpad memory and also sharing them data between the cores?

In addition,  is there any way to hack the MESI state of the cache line in the distributed tag directory (DTD)? 

Thanks in advance.


MPI programs dont run on MIC's across nodes or within the nodes

I am using the intel MIC to run sample MPI programs currently.

The program is a simple hello world program.

#include <stdio.h>
#include <mpi.h>

int main (argc, argv)
     int argc;
     char *argv[];
  int rank, size,len;

__MIC__ macro does not work

Hello everyone,

           To solve problems like this:   undefined reference to `_mm512_xxx_xxx(), I have added __MIC__ macro into my code.(

          But, these code between the

#ifdef __MIC__   




         never won't be executed.   


Phtrhead + offload

Hi I create a new thread and lanch offload code in this thread but I get this error code

offload error: cannot get function handles on the device 8117264 (error code 14)
The code likes as followings:

host code

  if (pthread_create(&d_thread, NULL, RunDevice, d_data))
       printf("\nCannot create device thread!\n");

thread code

void *RunDevice(void *ptr)

Xeon Phi Performance / Energy Tradeoff Issues


I have been doing experiments on Xeon Phi and ran an fibonacci(40) application with varied number of core allocations (i.e. number of cores). The energy consumption was measured through /sys/class/micras/power and performance (i.e. execution time) was measured using elapsed time.

I get the following trade-off:



I have OFED-MIC-3.5.2 with MPSS 3.4 and RHEL-7 running. When I do ibv_devices, ibv_deviceinfo I do see the scif interface as shown below. How do I run RDMA and IPoIB applications on this interface? The board shows a mic0:ib with an IP address but the performance on this link is just not there. I don't have any other infiniband interfaces on the host. At this time I am just trying to compile some existing RDMA based application to be the server on the host and the client to be on the Phi. Is this possible?

On Host:

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