1 //===--------------------- SchedulerStatistics.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 defines class SchedulerStatistics. Class SchedulerStatistics is a
11 /// View that listens to instruction issue events in order to print general
12 /// statistics related to the hardware schedulers.
13 ///
14 /// Example:
15 /// ========
16 ///
17 /// Schedulers - number of cycles where we saw N instructions issued:
18 /// [# issued], [# cycles]
19 ///  0,          6  (2.9%)
20 ///  1,          106  (50.7%)
21 ///  2,          97  (46.4%)
22 ///
23 /// Scheduler's queue usage:
24 /// [1] Resource name.
25 /// [2] Average number of used buffer entries.
26 /// [3] Maximum number of used buffer entries.
27 /// [4] Total number of buffer entries.
28 ///
29 ///  [1]            [2]        [3]        [4]
30 /// JALU01           0          0          20
31 /// JFPU01           15         18         18
32 /// JLSAGU           0          0          12
33 //
34 //===----------------------------------------------------------------------===//
35 
36 #ifndef LLVM_TOOLS_LLVM_MCA_SCHEDULERSTATISTICS_H
37 #define LLVM_TOOLS_LLVM_MCA_SCHEDULERSTATISTICS_H
38 
39 #include "llvm/ADT/SmallVector.h"
40 #include "llvm/MC/MCSubtargetInfo.h"
41 #include "llvm/MCA/View.h"
42 #include <map>
43 
44 namespace llvm {
45 namespace mca {
46 
47 class SchedulerStatistics final : public View {
48   const llvm::MCSchedModel &SM;
49   unsigned LQResourceID;
50   unsigned SQResourceID;
51 
52   unsigned NumIssued;
53   unsigned NumCycles;
54 
55   unsigned MostRecentLoadDispatched;
56   unsigned MostRecentStoreDispatched;
57 
58   // Tracks the usage of a scheduler's queue.
59   struct BufferUsage {
60     unsigned SlotsInUse;
61     unsigned MaxUsedSlots;
62     uint64_t CumulativeNumUsedSlots;
63   };
64 
65   using Histogram = std::map<unsigned, unsigned>;
66   Histogram IssueWidthPerCycle;
67 
68   std::vector<BufferUsage> Usage;
69 
70   void updateHistograms();
71   void printSchedulerStats(llvm::raw_ostream &OS) const;
72   void printSchedulerUsage(llvm::raw_ostream &OS) const;
73 
74 public:
75   SchedulerStatistics(const llvm::MCSubtargetInfo &STI);
76   void onEvent(const HWInstructionEvent &Event) override;
77   void onCycleBegin() override { NumCycles++; }
78   void onCycleEnd() override { updateHistograms(); }
79 
80   // Increases the number of used scheduler queue slots of every buffered
81   // resource in the Buffers set.
82   void onReservedBuffers(const InstRef &IR,
83                          llvm::ArrayRef<unsigned> Buffers) override;
84 
85   // Decreases by one the number of used scheduler queue slots of every
86   // buffered resource in the Buffers set.
87   void onReleasedBuffers(const InstRef &IR,
88                          llvm::ArrayRef<unsigned> Buffers) override;
89 
90   void printView(llvm::raw_ostream &OS) const override;
91   StringRef getNameAsString() const override { return "SchedulerStatistics"; }
92   bool isSerializable() const override { return false; }
93 };
94 } // namespace mca
95 } // namespace llvm
96 
97 #endif
98