From 7a4f9637639ce83191bc2d6e8485f9a9dfd949af Mon Sep 17 00:00:00 2001
From: Cedric Nugteren <web@cedricnugteren.nl>
Date: Sat, 23 Jul 2016 14:52:32 +0200
Subject: Further improvements to the XgemvFastRot kernel, properly enables
 coalescing now

---
 src/database/kernels/xgemv.hpp       |  2 +-
 src/kernels/level2/xgemv_fast.opencl | 84 ++++++++++++++++++------------------
 src/tuning/kernels/xgemv.cpp         |  8 +++-
 3 files changed, 50 insertions(+), 44 deletions(-)

(limited to 'src')

diff --git a/src/database/kernels/xgemv.hpp b/src/database/kernels/xgemv.hpp
index 6fb68858..3aa1863f 100644
--- a/src/database/kernels/xgemv.hpp
+++ b/src/database/kernels/xgemv.hpp
@@ -36,7 +36,7 @@ const Database::DatabaseEntry Database::XgemvSingle = {
   "Xgemv", Precision::kSingle, {
     { // AMD GPUs
       kDeviceTypeGPU, "AMD", {
-        { "AMD Radeon R9 M370X Compute Engine",              { {"WGS1",128}, {"WPT1",1}, {"VW2",1}, {"WGS2",128}, {"WPT2",1}, {"VW3",4}, {"WGS3",32}, {"WPT3",32} } },
+        { "AMD Radeon R9 M370X Compute Engine",              { {"WGS1",128}, {"WPT1",1}, {"VW2",1}, {"WGS2",128}, {"WPT2",1}, {"VW3",8}, {"WGS3",16}, {"WPT3",16} } },
         { "Hawaii",                                          { {"WGS1",128}, {"WPT1",1}, {"VW2",1}, {"WGS2",64}, {"WPT2",1}, {"VW3",1}, {"WGS3",64}, {"WPT3",1} } },
         { "Oland",                                           { {"WGS1",128}, {"WPT1",1}, {"VW2",1}, {"WGS2",64}, {"WPT2",1}, {"VW3",4}, {"WGS3",256}, {"WPT3",4} } },
         { "Pitcairn",                                        { {"WGS1",256}, {"WPT1",1}, {"VW2",1}, {"WGS2",64}, {"WPT2",1}, {"VW3",1}, {"WGS3",64}, {"WPT3",1} } },
diff --git a/src/kernels/level2/xgemv_fast.opencl b/src/kernels/level2/xgemv_fast.opencl
index 1d34de96..359c3770 100644
--- a/src/kernels/level2/xgemv_fast.opencl
+++ b/src/kernels/level2/xgemv_fast.opencl
@@ -204,10 +204,10 @@ __kernel void XgemvFastRot(const int m, const int n,
   const real beta = GetRealArg(arg_beta);
 
   // Local memory to store a tile of the matrix (for coalescing)
-  __local real tile[WGS3 * WPT3];
+  __local real tile[WPT3][WGS3];
   const int lid = get_local_id(0);
-  const int lid_mod = lid % WPT3;
-  const int lid_div = lid / WPT3;
+  const int lid_mod = lid % (WPT3/VW3);
+  const int lid_div = lid / (WPT3/VW3);
 
   // Local memory for the vector X
   __local real xlm[WPT3];
@@ -225,45 +225,45 @@ __kernel void XgemvFastRot(const int m, const int n,
     // Loads the matrix A into local memory
     #pragma unroll
     for (int kl=0; kl<WPT3/VW3; ++kl) {
-      const int x = (kwg/VW3) + kl;
-      const int y = get_group_id(0) * WGS3 + lid;
+      const int x = (kwg/VW3) + lid_mod;
+      const int y = get_group_id(0) * WGS3 + lid_div * (WPT3/VW3) + kl;
       realVFR avec = agm[(a_ld/VW3) * y + x];
       #if VW3 == 1
-        tile[(kl*VW3 + 0) * WGS3 + lid] = avec;
+        tile[kl*VW3 + 0][lid] = avec;
       #elif VW3 == 2
-        tile[(kl*VW3 + 0) * WGS3 + lid] = avec.x;
-        tile[(kl*VW3 + 1) * WGS3 + lid] = avec.y;
+        tile[kl*VW3 + 0][lid] = avec.x;
+        tile[kl*VW3 + 1][lid] = avec.y;
       #elif VW3 == 4
-        tile[(kl*VW3 + 0) * WGS3 + lid] = avec.x;
-        tile[(kl*VW3 + 1) * WGS3 + lid] = avec.y;
-        tile[(kl*VW3 + 2) * WGS3 + lid] = avec.z;
-        tile[(kl*VW3 + 3) * WGS3 + lid] = avec.w;
+        tile[kl*VW3 + 0][lid] = avec.x;
+        tile[kl*VW3 + 1][lid] = avec.y;
+        tile[kl*VW3 + 2][lid] = avec.z;
+        tile[kl*VW3 + 3][lid] = avec.w;
       #elif VW3 == 8
-        tile[(kl*VW3 + 0) * WGS3 + lid] = avec.s0;
-        tile[(kl*VW3 + 1) * WGS3 + lid] = avec.s1;
-        tile[(kl*VW3 + 2) * WGS3 + lid] = avec.s2;
-        tile[(kl*VW3 + 3) * WGS3 + lid] = avec.s3;
-        tile[(kl*VW3 + 4) * WGS3 + lid] = avec.s4;
-        tile[(kl*VW3 + 5) * WGS3 + lid] = avec.s5;
-        tile[(kl*VW3 + 6) * WGS3 + lid] = avec.s6;
-        tile[(kl*VW3 + 7) * WGS3 + lid] = avec.s7;
+        tile[kl*VW3 + 0][lid] = avec.s0;
+        tile[kl*VW3 + 1][lid] = avec.s1;
+        tile[kl*VW3 + 2][lid] = avec.s2;
+        tile[kl*VW3 + 3][lid] = avec.s3;
+        tile[kl*VW3 + 4][lid] = avec.s4;
+        tile[kl*VW3 + 5][lid] = avec.s5;
+        tile[kl*VW3 + 6][lid] = avec.s6;
+        tile[kl*VW3 + 7][lid] = avec.s7;
       #elif VW3 == 16
-        tile[(kl*VW3 + 0) * WGS3 + lid] = avec.s0;
-        tile[(kl*VW3 + 1) * WGS3 + lid] = avec.s1;
-        tile[(kl*VW3 + 2) * WGS3 + lid] = avec.s2;
-        tile[(kl*VW3 + 3) * WGS3 + lid] = avec.s3;
-        tile[(kl*VW3 + 4) * WGS3 + lid] = avec.s4;
-        tile[(kl*VW3 + 5) * WGS3 + lid] = avec.s5;
-        tile[(kl*VW3 + 6) * WGS3 + lid] = avec.s6;
-        tile[(kl*VW3 + 7) * WGS3 + lid] = avec.s7;
-        tile[(kl*VW3 + 8) * WGS3 + lid] = avec.s8;
-        tile[(kl*VW3 + 9) * WGS3 + lid] = avec.s9;
-        tile[(kl*VW3 + 10) * WGS3 + lid] = avec.sA;
-        tile[(kl*VW3 + 11) * WGS3 + lid] = avec.sB;
-        tile[(kl*VW3 + 12) * WGS3 + lid] = avec.sC;
-        tile[(kl*VW3 + 13) * WGS3 + lid] = avec.sD;
-        tile[(kl*VW3 + 14) * WGS3 + lid] = avec.sE;
-        tile[(kl*VW3 + 15) * WGS3 + lid] = avec.sF;
+        tile[kl*VW3 + 0][lid] = avec.s0;
+        tile[kl*VW3 + 1][lid] = avec.s1;
+        tile[kl*VW3 + 2][lid] = avec.s2;
+        tile[kl*VW3 + 3][lid] = avec.s3;
+        tile[kl*VW3 + 4][lid] = avec.s4;
+        tile[kl*VW3 + 5][lid] = avec.s5;
+        tile[kl*VW3 + 6][lid] = avec.s6;
+        tile[kl*VW3 + 7][lid] = avec.s7;
+        tile[kl*VW3 + 8][lid] = avec.s8;
+        tile[kl*VW3 + 9][lid] = avec.s9;
+        tile[kl*VW3 + 10][lid] = avec.sA;
+        tile[kl*VW3 + 11][lid] = avec.sB;
+        tile[kl*VW3 + 12][lid] = avec.sC;
+        tile[kl*VW3 + 13][lid] = avec.sD;
+        tile[kl*VW3 + 14][lid] = avec.sE;
+        tile[kl*VW3 + 15][lid] = avec.sF;
       #endif
     }
 
@@ -272,11 +272,13 @@ __kernel void XgemvFastRot(const int m, const int n,
 
     // The multiply-add function (rotated)
     #pragma unroll
-    for (int kl=0; kl<WPT3; ++kl) {
-      const int k = kl * (WGS3/WPT3) + lid_div;
-      real aval = tile[k * WPT3 + lid_mod];
-      real xval = xlm[kl];
-      MultiplyAdd(acc, xval, aval);
+    for (int kl=0; kl<WPT3/VW3; ++kl) {
+      #pragma unroll
+      for (int v=0; v<VW3; ++v) {
+        real aval = tile[lid_mod*VW3 + v][lid_div * (WPT3/VW3) + kl];
+        real xval = xlm[kl*VW3 + v];
+        MultiplyAdd(acc, xval, aval);
+      }
     }
 
     // Synchronizes all threads in a workgroup
diff --git a/src/tuning/kernels/xgemv.cpp b/src/tuning/kernels/xgemv.cpp
index b69e4352..8446e4a9 100644
--- a/src/tuning/kernels/xgemv.cpp
+++ b/src/tuning/kernels/xgemv.cpp
@@ -61,7 +61,7 @@ class TuneXgemv {
 
   // Sets the tuning parameters and their possible values
   static void SetParameters(cltune::Tuner &tuner, const size_t id) {
-    tuner.AddParameter(id, "WGS"+std::to_string(V), {32, 64, 128, 256});
+    tuner.AddParameter(id, "WGS"+std::to_string(V), {16, 32, 64, 128});
     if (V==1 || V==2) { tuner.AddParameter(id, "WPT"+std::to_string(V), {1, 2, 4}); }
     else { tuner.AddParameter(id, "WPT"+std::to_string(V), {1, 2, 4, 8, 16, 32}); }
     if (V==2 || V==3) { tuner.AddParameter(id, "VW"+std::to_string(V), {1, 2, 4, 8}); }
@@ -69,10 +69,14 @@ class TuneXgemv {
 
   // Sets the constraints and local memory size
   static void SetConstraints(cltune::Tuner &tuner, const size_t id) {
-    auto MultipleOfX = [] (std::vector<size_t> v) { return IsMultiple(v[0], v[1]); };
     if (V==2 || V==3) {
+      auto MultipleOfX = [] (std::vector<size_t> v) { return IsMultiple(v[0], v[1]); };
       tuner.AddConstraint(id, MultipleOfX, {"WPT"+std::to_string(V), "VW"+std::to_string(V)});
     }
+    if (V==3) {
+      auto LargerOrEqual = [] (std::vector<size_t> v) { return v[0] >= v[1]; };
+      tuner.AddConstraint(id, LargerOrEqual, {"WGS"+std::to_string(V), "WPT"+std::to_string(V)});
+    }
   }
   static void SetLocalMemorySize(cltune::Tuner &tuner, const size_t id, const Arguments<T> &args) {
     if (V==1 || V==2) {
-- 
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