Option "-z defs" is no longer needed to detect missing symbols in code targeting Intel MIC Architecture at link time

Prior to Intel® Compiler 15.0 in the offload compilation model, the binaries targeting the Intel MIC Architecture were generated as dynamic libraries (.so). Dynamic libraries do not need all referenced variables or routines to be resolved during linking as these can be resolved during load time. This behavior could mask some missing variable or routine in the application resulting in a failure during load time. In order to identify and resolve all missing symbols at link time, option "-z defs" must be provided to the linker.

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  • MPSS 2.1 not able to start

    I've reinstalled MPSS drivers on the server with Sandybridge processor and RHEL-6.1. The driver used was MPSS-2.1 Gold of RHEL6.2. While installing the drivers, I've rebuilt the rpm by using the source rpm src/intel-mic-kmod-2.1.6720-23.el6.src.rpm. After successful installation, micctrl --initdefaults worked well. But the "service mpss start" command shown "Failed". But "service mpss status" shows running, as below:


    Poor speed up in Phi

    I am trying to speed up a matrix multiplication code in in intel coprocessor. I am getting exact speed up in host but In coprocessor performance is very poor compare to host. I compiled code with -O3 flag to enable auto vectorization. And i am using following environment variables

    export XEONPHI_KMP_PLACE_THREADS=60C,4t/30C,2t......
    export XEONPHI_KMP_AFFINITY=compact,granularity=fine


    MATLAB Automatic Offload Elementwise Operations


      I got automatic offload running for MATLAB and was able to test matrix multiplication and some LAPACK functions running on the Phi. However, I was wondering if it was possible to run element-wise operations on the Phi, for example:




    Free memory after offload region - memleak?


    I am trying to offload some of my code, which works without any errors. The problem I'm facing is, that while the code below runs without any errors, the memory usage of the program increases over time (when NUM2 is big enough it rises up to 32GB+). Since I think I am freeing it properly (runs fine without increased memory usage when I run it on the host without offloading), I can not further explain what is causing this memory leak.


    How to compile/install/use third party library


    I am using compiler assisted offload in my application, explicitly specifying which computations should be transferred to the Xeon Phi. Things are working correctly, but now I got to the point where I need to use a third party library in the part of the application that is offloaded to the Phi. If it is of any use, the library under consideration is PRIMME (, code and documentation found at

    Best Practical practice for Server/Dev Environments

    At long last I am making my CentOS boot stick and copying BIOS versions to another stick.   Hopefully the magic smoke will not escape...

    1 Primary Physical Box -3-4 mics -  2-3 small Projects, 4-6 remote users not terribly concurrent.

    Some R, some Pynum, some C++ a bit of this a dash of that...

    XEN -> and then carve up a stack of administrative servers and development vms?

    Centos -> VMWare>

    Something else...

    Unable to compile the code for Xeonphi

    I wrote a MPI Program for running on Xeon phi in native mode.
    When I tried to compile the code, the following errors are coming.

    $mpicc test.c -o test -mmic

    /usr/bin/ld: skipping incompatible /opt/intel//impi/ when searching for -lmpifort
    /usr/bin/ld: skipping incompatible /opt/intel//impi/ when searching for -lmpifort
    /usr/bin/ld: cannot find -lmpifort
    collect2: ld returned 1 exit status

    Please help me out.

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