1 //===--------------------- DispatchStatistics.h -----------------*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 /// \file 9 /// 10 /// This file implements a view that prints a few statistics related to the 11 /// dispatch logic. It collects and analyzes instruction dispatch events as 12 /// well as static/dynamic dispatch stall events. 13 /// 14 /// Example: 15 /// ======== 16 /// 17 /// Dynamic Dispatch Stall Cycles: 18 /// RAT - Register unavailable: 0 19 /// RCU - Retire tokens unavailable: 0 20 /// SCHEDQ - Scheduler full: 42 21 /// LQ - Load queue full: 0 22 /// SQ - Store queue full: 0 23 /// GROUP - Static restrictions on the dispatch group: 0 24 /// 25 /// 26 /// Dispatch Logic - number of cycles where we saw N micro opcodes dispatched: 27 /// [# dispatched], [# cycles] 28 /// 0, 15 (11.5%) 29 /// 2, 4 (3.1%) 30 /// 31 //===----------------------------------------------------------------------===// 32 33 #ifndef LLVM_TOOLS_LLVM_MCA_DISPATCHVIEW_H 34 #define LLVM_TOOLS_LLVM_MCA_DISPATCHVIEW_H 35 36 #include "llvm/ADT/SmallVector.h" 37 #include "llvm/MC/MCSubtargetInfo.h" 38 #include "llvm/MCA/View.h" 39 #include <map> 40 41 namespace llvm { 42 namespace mca { 43 44 class DispatchStatistics : public View { 45 unsigned NumDispatched; 46 unsigned NumCycles; 47 48 // Counts dispatch stall events caused by unavailability of resources. There 49 // is one counter for every generic stall kind (see class HWStallEvent). 50 llvm::SmallVector<unsigned, 8> HWStalls; 51 52 using Histogram = std::map<unsigned, unsigned>; 53 Histogram DispatchGroupSizePerCycle; 54 55 void updateHistograms() { 56 DispatchGroupSizePerCycle[NumDispatched]++; 57 NumDispatched = 0; 58 } 59 60 void printDispatchHistogram(llvm::raw_ostream &OS) const; 61 62 void printDispatchStalls(llvm::raw_ostream &OS) const; 63 64 public: 65 DispatchStatistics() 66 : NumDispatched(0), NumCycles(0), 67 HWStalls(HWStallEvent::LastGenericEvent) {} 68 69 void onEvent(const HWStallEvent &Event) override; 70 71 void onEvent(const HWInstructionEvent &Event) override; 72 73 void onCycleBegin() override { NumCycles++; } 74 75 void onCycleEnd() override { updateHistograms(); } 76 77 void printView(llvm::raw_ostream &OS) const override { 78 printDispatchStalls(OS); 79 printDispatchHistogram(OS); 80 } 81 StringRef getNameAsString() const override { return "DispatchStatistics"; } 82 json::Value toJSON() const override; 83 }; 84 } // namespace mca 85 } // namespace llvm 86 87 #endif 88