We recently heard from an NMath user:

Cephalexin 250mg capsules, I am seeing a memory accumulation in my application (which uses NMath Core 2.5). Amoxicillin 500 mg sinus infection, From my memory profiler it looks like it could be an allocation in DotNetBlas.Product(), within the MKL dgemm() function, keflex 500mg dosage. Keflex 750 mg dosage, I understand that MKL is designed such that memory is not released until the application closes. However, penicillin v 250 mg, Keflex 500 mg qid, as this application runs in new worker threads all the time, I wondering if each new thread is holding onto it's own memory for Product(), pen vk 250. Pen vk 250 mg, I've tried setting the system variable MKL_DISABLE_FAST_MM - but this seems to have made no difference - would I expect this to have an immediate effect (after re-starting the application). Is there any other way within NMath to force MKL to release memory?

It's true that for performance reasons, memory allocated by the Intel Math Kernel Library (MKL) is not released, cephalexin 250mg capsules. This is by design and is a one-time occurrence for MKL routines that require workspace memory buffers, keflex pulvules 500mg. Keflex 100 mg, However, this workspace appears to be allocated on a per-thread basis, keflex 500 mg dosage, Keflex capsules 500mg, which can be a problem for applications that spawn large numbers of threads. As the MKL documentation delicately puts it, cephalexin 500 mg for dogs, Keflex 500mg dosage, "the user should be aware that some tools might report this as a memory leak".

There are two solutions for multithreaded applications to avoid continuous memory accumulation:

1. Use a thread pool, amoxicillin 500 mg sinus infection, Pen vee k 250 mg, so the number of new threads is bounded by the size of the pool.


2. Use the MKL_FreeBuffers() function to free the memory allocated by the MKL memory manager.

The MKL_FreeBuffers() function is not currently exposed in NMath, but will be added in the next release, keflex 750 mg dosage. Penicillin v 250 mg, In the meantime, you can add this function to Kernel.cpp in NMath Core, keflex 500 mg dosage, Keflex capsules 500mg, and rebuild:

static void MklFreeBuffers() {

  BLAS_PREFIX(MKL_FreeBuffers());

}

Or, if you want some console output to confirm that memory is being released, keflex 100 mg, Pen vee k 250 mg, try this:

static void MklFreeBuffers() {

  MKL_INT64 AllocatedBytes;

  int N_AllocatedBuffers;
  AllocatedBytes = MKL_MemStat(&N_ AllocatedBuffers);

  System::Console::WriteLine("BEFORE: " + (long)AllocatedBytes + " bytes in " + N_AllocatedBuffers + " buffers");
  BLAS_PREFIX(MKL_FreeBuffers()) ;
  AllocatedBytes = MKL_MemStat(&N_AllocatedBuffers);

  System::Console::WriteLine("AFTER: " + (long)AllocatedBytes + " bytes in " + N_AllocatedBuffers + " buffers");

}

Once you've rebuilt NMath Core, you'd use the new method like so:

using CenterSpace.NMath.Kernel;

.., keflex 500 mg qid.  Pen vk 250 mg, DotNetBlas.MklFreeBuffers();

Note that some care should be taken when calling MklFreeBuffers(), since a drop in performance may occur for any subsequent MKL functions within the same thread, keflex 500mg dosage, Cephalexin 500 mg for dogs, due to reallocation of buffers. Furthermore, given the cost of freeing the buffers themselves, rather than calling MklFreeBuffers() at the end of each thread, it might be more performant to do so after every n threads, or perhaps even based on the total memory usage of your program.

Ken.

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