[ONCPUML-7] arm_compute support for ND parallelism

Currently 1D ranges of work are specified by the scheduler
via two integers, start and end.  This limit opportunities
for advance parallelism and scheduling

This patch expands the interfaces to allow for ND parallism.

`GemmCommon::get_window_size` now returns an `NDRange` specifying the work
in N-dimensions rather than with the single integer it used prior (1D)

Execute now takes an `NDCoordinate` which specifies an `NDRange` with a start
position for that work along with an `NDCoordinate` to specify the thread location

In addition to expanding the interface to enable this functionality,
we have added the capability to SGEMM when the number of threads is high
this has the effective of allowing a much greater degree of parallelism
where te problem dimension would previously have limited the number of threads.

Change-Id: I3e1a8b7276216627bec4ff6f24ac2147552ea9fb
Signed-off-by: Joseph Dobson <joseph.dobson@arm.com>
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/2962
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Gian Marco Iodice <gianmarco.iodice@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>

1 files changed, 30 insertions, 10 deletions

diff --git a/arm_compute/core/NEON/kernels/assembly/gemm_common.hpp b/arm_compute/core/NEON/kernels/assembly/gemm_common.hpp
index d17fd5fe97..ea9b524e15 100644
--- a/arm_compute/core/NEON/kernels/assembly/gemm_common.hpp
+++ b/arm_compute/core/NEON/kernels/assembly/gemm_common.hpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2019 Arm Limited.
+ * Copyright (c) 2017-2020 Arm Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -23,7 +23,10 @@
  */
 #pragma once
 
+#include "arm_compute/core/NEON/kernels/assembly/arm_gemm_compute_iface.hpp"
+
 #include <cstddef>
+#include <cassert>
 
 #define UNUSED(x)   (void)(x)
 
@@ -51,10 +54,10 @@ public:
                                           void *C, const int ldc, const int C_batch_stride, const int C_multi_stride,
                                     const void *bias, /* no row or batch stride needed */   const int bias_multi_stride) = 0;
 
-    /* For threading, we divide the work into some number of units and work
-     * out internally what unit corresponds to what work.  This returns the
-     * total number of units.  */
-    virtual unsigned int get_window_size() const = 0;
+    /** @returns an ndrange containing ranges of the compute space which can be
+     * broken up and parallelised over
+     */
+    virtual ndrange_t get_window_size() const = 0;
 
     /* The maximum thread count is specified when the GEMM is created.  Some
      * implementations need to know how many threads will actually run in
@@ -73,9 +76,12 @@ public:
     /* Whether this GEMM can be dynamically scheduled or not. */
     virtual bool supports_dynamic_scheduling() const { return false; }
 
-    /* Actually do the work.  Provide a threadid to index any per-thread
-     * buffers, and a start/end range to indicate which work to do.  */
-    virtual void execute(unsigned int, unsigned int, int) = 0;
+    /** Main execute member fucntion
+     * @param [in] work_range     specifies the range of work we want to be computed, total range defined by get_window_size()
+     * @param [in] thread_locator where are we inside of the thread space
+     * @naram [in] threadid       a unique threadid
+     */
+    virtual void execute(const ndcoord_t& work_range, const ndcoord_t& thread_locator, int threadid) = 0;
 
     /*** Working space interface (optional) ***/
     /* Total number of bytes of temporary working space needed.  If zero, it's not necessary to call set_working_space(). */
@@ -108,8 +114,7 @@ public:
     virtual ~IGemmCommon() { }
 };
 
-/*
- * "Real" GemmCommon class which is templated on the operand and return types.
+/* "Real" GemmCommon class which is templated on the operand and return types.
  *
  * In addition to correctly typed versions of the functions that operate on
  * operand and return data, this class provides a default implementation of
@@ -178,4 +183,19 @@ public:
     }
 };
 
+template<typename GemmKernel>
+inline
+int unsigned get_total_window_size(const GemmKernel& kernel)
+{
+    auto window=kernel.get_window_size();
+
+    unsigned int total = 1;
+    for(unsigned i = 0; i != arm_gemm::ndrange_max; ++i)
+    {
+        total *= window.get_size(i);
+    }
+
+    return total;
+}
+
 } // namespace arm_gemm