SWDEV-526855 - Modify the SIMDPerCU calculation for gfx1250/1. (#275)

Author: kjayapra-amd

hipamd/src/hip_platform.cpp

@@ -404,8 +404,14 @@ hipError_t ihipOccupancyMaxActiveBlocksPerMultiprocessor(
     const size_t SgprWaves = maxSGPRs / amd::alignUp(wrkGrpInfo->usedSGPRs_, 16);
     GprWaves = std::min(VgprWaves, SgprWaves);
   }
-  uint32_t simdPerCU = (device.isa().versionMajor() <= 9) ? device.info().simdPerCU_
-                                                          : (wrkGrpInfo->isWGPMode_ ? 4 : 2);
+
+  // The table contains SIMD per CU, not per WGP, so when WGP mode is set on kernel metadata,
+  // multiply the number of SIMDs by 2, to account for 2CUs in 1 WGP.
+  uint32_t simdPerCU = device.isa().simdPerCU();
+  if (wrkGrpInfo->isWGPMode_) {
+    simdPerCU  *= 2;
+  }
+
   const size_t alu_occupancy = simdPerCU * std::min(MaxWavesPerSimd, GprWaves);
   const int alu_limited_threads = alu_occupancy * wrkGrpInfo->wavefrontSize_;