Abort when Scratch Space size exceeds HW limit on last retry attempt only

When Scratch Space size exceeds HW limit, we also need to check if the current compilation is the final retry attempt.
On retry, we may end up reducing spills and consequently SS usage such that the HW limit is not hit. Only abort compilation if the final try still has SS exceeding the HW limit.

Author: dlei6g

IGC/Compiler/CISACodeGen/CISABuilder.cpp

@@ -6205,8 +6205,7 @@ namespace IGC
             context->SetSIMDInfo(SIMD_SKIP_SPILL, m_program->m_dispatchSize, m_program->m_ShaderDispatchMode);
             // Set spill size despite VISA terminates with VISA_SPILL error code.
             // This member is checked later for OOB scratch.
-            m_program->ProgramOutput()->m_scratchSpaceUsedBySpills =
-                jitInfo->stats.spillMemUsed;
+            m_program->ProgramOutput()->m_scratchSpaceUsedBySpills = jitInfo->stats.spillMemUsed;
             return;
         }
 

IGC/Compiler/CISACodeGen/OpenCLKernelCodeGen.cpp

@@ -3456,7 +3456,7 @@ namespace IGC
 
     static bool exceedMaxScratchUse(CShader* shader, OpenCLProgramContext* ctx)
     {
-        return getScratchUse(shader, ctx) >
+        return shader && getScratchUse(shader, ctx) >
             shader->ProgramOutput()->m_scratchSpaceSizeLimit;
     }
 
@@ -3638,33 +3638,29 @@ namespace IGC
         }
     }
 
-    static void verifyOOBScratch(OpenCLProgramContext *ctx,
+    static bool verifyHasOOBScratch(OpenCLProgramContext *ctx,
                                  COpenCLKernel *simd8Shader,
                                  COpenCLKernel *simd16Shader,
                                  COpenCLKernel *simd32Shader) {
         auto verify = [ctx](CShader *shader) {
             if (exceedMaxScratchUse(shader, ctx)) {
-              std::string errorMsg =
-                  "total scratch space exceeds HW "
-                  "supported limit for kernel " +
-                  shader->entry->getName().str() + ": " +
-                  std::to_string(getScratchUse(shader, ctx)) + " bytes (max permitted PTSS " +
-                  std::to_string(shader->ProgramOutput()->m_scratchSpaceSizeLimit) +
-                  " bytes)";
-
-              ctx->EmitError(errorMsg.c_str(), nullptr);
+                return true;
             }
+            return false;
         };
 
         // Need to check if simd* shader is not nullptr and its vISA compile status,
         // since it may be created without going through full vISA compilation and
         // the spill size record may be invalid
+        bool result = false;
         if (simd8Shader && !COpenCLKernel::IsVisaCompileStatusFailureForShader(simd8Shader))
-          verify(simd8Shader);
+          result |= verify(simd8Shader);
         else if (simd16Shader && !COpenCLKernel::IsVisaCompileStatusFailureForShader(simd16Shader))
-          verify(simd16Shader);
+          result |= verify(simd16Shader);
         else if (simd32Shader && !COpenCLKernel::IsVisaCompileStatusFailureForShader(simd32Shader))
-          verify(simd32Shader);
+          result |= verify(simd32Shader);
+
+        return result;
     }
 
     static void CodeGen(OpenCLProgramContext* ctx, CShaderProgram::KernelShaderMap& shaders)
@@ -3881,9 +3877,36 @@ namespace IGC
                     GatherDataForDriver(ctx, simd16Shader, std::move(pKernel), pFunc, pMdUtils, SIMDMode::SIMD16);
                 else if (COpenCLKernel::IsValidShader(simd8Shader))
                     GatherDataForDriver(ctx, simd8Shader, std::move(pKernel), pFunc, pMdUtils, SIMDMode::SIMD8);
-                else
-                  // Verify if compilation failed due to OOB scratch
-                  verifyOOBScratch(ctx, simd8Shader, simd16Shader, simd32Shader);
+                else if (verifyHasOOBScratch(ctx, simd8Shader, simd16Shader, simd32Shader))
+                {
+                    // Get the simd* shader with the OOB access.
+                    COpenCLKernel* shader =
+                        exceedMaxScratchUse(simd32Shader, ctx) ? simd32Shader :
+                        exceedMaxScratchUse(simd16Shader, ctx) ? simd16Shader :
+                        exceedMaxScratchUse(simd8Shader, ctx) ? simd8Shader :
+                        nullptr;
+
+                    IGC_ASSERT(shader);
+
+                    if (!ctx->m_retryManager.IsLastTry())
+                    {
+                        // If this is not the last try, force retry on this kernel to potentially avoid
+                        // OOB access on the next try by reducing spill size and thus SS usage.
+                        ctx->m_retryManager.kernelSet.insert(shader->entry->getName().str());
+                    }
+                    else
+                    {
+                        std::string errorMsg =
+                            "total scratch space exceeds HW "
+                            "supported limit for kernel " +
+                            shader->entry->getName().str() + ": " +
+                            std::to_string(getScratchUse(shader, ctx)) + " bytes (max permitted PTSS " +
+                            std::to_string(shader->ProgramOutput()->m_scratchSpaceSizeLimit) +
+                            " bytes)";
+
+                        ctx->EmitError(errorMsg.c_str(), nullptr);
+                    }
+                }
             }
         }
 

visa/RegAlloc.cpp

@@ -3101,7 +3101,6 @@ int regAlloc(IR_Builder &builder, PhyRegPool &regPool, G4_Kernel &kernel) {
       builder.criticalMsgStream()
           << "Total scratch size used by shader exceeds platform capability: "
           << totalScratchUsed << "\n";
-      vISA_ASSERT(false, "spill size exceeds platform capability");
       return VISA_SPILL;
     }
   }