add support for split barriers

This may also be helpful to keep subgroups running approximately together, which could also improve cache utilization.
bashbaug · Jan 19, 2024 · d09b982 · d09b982
1 parent 0fb3d66
commit d09b982
Showing 1 changed file with 53 additions and 0 deletions.
diff --git a/samples/99_matrixexperiments/matrix_kernel_tiled.cl b/samples/99_matrixexperiments/matrix_kernel_tiled.cl
@@ -10,6 +10,17 @@
 #error "NN is undefined!  This should be defined as the number of matrix tiles in the N dimension."
 #endif
 
+#if !defined(cl_intel_split_work_group_barrier) || defined(NO_SPLIT_BARRIERS)
+#if !defined(cl_intel_split_work_group_barrier)
+#warning "Unexpected: cl_intel_split_work_group_barrier is not supported?"
+#endif
+#define split_barrier_arrive()
+#define split_barrier_wait()
+#else
+#define split_barrier_arrive()  intel_work_group_barrier_arrive(0)
+#define split_barrier_wait()    intel_work_group_barrier_wait(0)
+#endif
+
 #define MM_KERNEL_NAMEX(PREFIX, tM, tN, MM, NN) PREFIX ## _m ## tM ## _n ## tN ## _ ## MM ## x ## NN
 #define MM_KERNEL_NAME(PREFIX, tM, tN, MM, NN)  MM_KERNEL_NAMEX(PREFIX, tM, tN, MM, NN)
 
@@ -36,6 +47,8 @@ kernel void MM_KERNEL_NAME(bfloat16_dpas_rowmajor_tiled, 8, 8, MM, NN)(global fl
         }
     }
 
+    split_barrier_arrive();
+
     for (int k = 0; k < K; k += tK) {
         int8    aData[MM];
         for (int mm = 0; mm < MM; mm++) {
@@ -52,8 +65,13 @@ kernel void MM_KERNEL_NAME(bfloat16_dpas_rowmajor_tiled, 8, 8, MM, NN)(global fl
                 sum[mm][nn] = mat_mul_sg8(aData[mm], bData[nn], sum[mm][nn]);
             }
         }
+
+        split_barrier_wait();
+        split_barrier_arrive();
     }
 
+    split_barrier_wait();
+
     for (int nn = 0; nn < NN; nn++) {
         for (int mm = 0; mm < MM; mm++) {
             store_c_rowmajor_fp32_m8_nx(C, sum[mm][nn], m + mm * tM, n + nn * tN, N);
@@ -77,6 +95,8 @@ kernel void MM_KERNEL_NAME(bfloat16_dpas_vnni_tiled, 8, 8, MM, NN)(global float*
         }
     }
 
+    split_barrier_arrive();
+
     for (int k = 0; k < K; k += tK) {
         int8    aData[MM];
         for (int mm = 0; mm < MM; mm++) {
@@ -93,8 +113,13 @@ kernel void MM_KERNEL_NAME(bfloat16_dpas_vnni_tiled, 8, 8, MM, NN)(global float*
                 sum[mm][nn] = mat_mul_sg8(aData[mm], bData[nn], sum[mm][nn]);
             }
         }
+
+        split_barrier_wait();
+        split_barrier_arrive();
     }
 
+    split_barrier_wait();
+
     for (int mm = 0; mm < MM; mm++) {
         for (int nn = 0; nn < NN; nn++) {
             store_c_rowmajor_fp32_m8_nx(C, sum[mm][nn], m + mm * tM, n + nn * tN, N);
@@ -120,6 +145,8 @@ kernel void MM_KERNEL_NAME(bfloat16_dpas_rowmajor_tiled, 8, 16, MM, NN)(global f
         }
     }
 
+    split_barrier_arrive();
+
     for (int k = 0; k < K; k += tK) {
         short8  aData[MM];
         for (int mm = 0; mm < MM; mm++) {
@@ -136,8 +163,13 @@ kernel void MM_KERNEL_NAME(bfloat16_dpas_rowmajor_tiled, 8, 16, MM, NN)(global f
                 sum[mm][nn] = mat_mul_sg16(aData[mm], bData[nn], sum[mm][nn]);
             }
         }
+
+        split_barrier_wait();
+        split_barrier_arrive();
     }
 
+    split_barrier_wait();
+
     for (int mm = 0; mm < MM; mm++) {
         for (int nn = 0; nn < NN; nn++) {
             store_c_rowmajor_fp32_m8_nx(C, sum[mm][nn], m + mm * tM, n + nn * tN, N);
@@ -161,6 +193,8 @@ kernel void MM_KERNEL_NAME(bfloat16_dpas_vnni_tiled, 8, 16, MM, NN)(global float
         }
     }
 
+    split_barrier_arrive();
+
     for (int k = 0; k < K; k += tK) {
         short8  aData[MM];
         for (int mm = 0; mm < MM; mm++) {
@@ -177,8 +211,13 @@ kernel void MM_KERNEL_NAME(bfloat16_dpas_vnni_tiled, 8, 16, MM, NN)(global float
                 sum[mm][nn] = mat_mul_sg16(aData[mm], bData[nn], sum[mm][nn]);
             }
         }
+
+        split_barrier_wait();
+        split_barrier_arrive();
     }
 
+    split_barrier_wait();
+
     for (int mm = 0; mm < MM; mm++) {
         for (int nn = 0; nn < NN; nn++) {
             store_c_rowmajor_fp32_m8_nx(C, sum[mm][nn], m + mm * tM, n + nn * tN, N);
@@ -205,6 +244,8 @@ kernel void MM_KERNEL_NAME(bfloat16_dpas_blockread_rowmajor_tiled, 8, 16, MM, NN
         }
     }
 
+    split_barrier_arrive();
+
     for (int k = 0; k < K; k += tK) {
         short8  aData[MM];
         //if (MM % 2 == 0) {
@@ -229,8 +270,13 @@ kernel void MM_KERNEL_NAME(bfloat16_dpas_blockread_rowmajor_tiled, 8, 16, MM, NN
                 sum[mm][nn] = mat_mul_sg16(aData[mm], bData[nn], sum[mm][nn]);
             }
         }
+
+        split_barrier_wait();
+        split_barrier_arrive();
     }
 
+    split_barrier_wait();
+
     for (int mm = 0; mm < MM; mm++) {
         for (int nn = 0; nn < NN; nn++) {
             intel_subgroup_block_write_u32_m8k16(C, N * sizeof(float), M, N * sizeof(float), (int2)(n + nn * tN, m + mm * tM), as_uint8(sum[mm][nn]));
@@ -255,6 +301,8 @@ kernel void MM_KERNEL_NAME(bfloat16_dpas_blockread_vnni_tiled, 8, 16, MM, NN)(gl
         }
     }
 
+    split_barrier_arrive();
+
     for (int k = 0; k < K; k += tK) {
         short8  aData[MM];
         //if (MM % 2 == 0) {
@@ -279,8 +327,13 @@ kernel void MM_KERNEL_NAME(bfloat16_dpas_blockread_vnni_tiled, 8, 16, MM, NN)(gl
                 sum[mm][nn] = mat_mul_sg16(aData[mm], bData[nn], sum[mm][nn]);
             }
         }
+
+        split_barrier_wait();
+        split_barrier_arrive();
     }
 
+    split_barrier_wait();
+
     for (int mm = 0; mm < MM; mm++) {
         for (int nn = 0; nn < NN; nn++) {
             intel_subgroup_block_write_u32_m8k16(C, N * sizeof(float), M, N * sizeof(float), (int2)(n + nn * tN, m + mm * tM), as_uint8(sum[mm][nn]));