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