tools/llvm-mca/Views/ResourcePressureView.h

   1 //===--------------------- ResourcePressureView.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 define class ResourcePressureView.
  11 /// Class ResourcePressureView observes hardware events generated by
  12 /// the Pipeline object and collects statistics related to resource usage at
  13 /// instruction granularity.
  14 /// Resource pressure information is then printed out to a stream in the
  15 /// form of a table like the one from the example below:
  16 ///
  17 /// Resources:
  18 /// [0] - JALU0
  19 /// [1] - JALU1
  20 /// [2] - JDiv
  21 /// [3] - JFPM
  22 /// [4] - JFPU0
  23 /// [5] - JFPU1
  24 /// [6] - JLAGU
  25 /// [7] - JSAGU
  26 /// [8] - JSTC
  27 /// [9] - JVIMUL
  28 ///
  29 /// Resource pressure per iteration:
  30 /// [0]    [1]    [2]    [3]    [4]    [5]    [6]    [7]    [8]    [9]
  31 /// 0.00   0.00   0.00   0.00   2.00   2.00   0.00   0.00   0.00   0.00
  32 ///
  33 /// Resource pressure by instruction:
  34 /// [0]  [1]  [2]  [3]  [4]  [5]  [6]  [7]  [8]  [9]  Instructions:
  35 ///  -    -    -    -    -   1.00  -    -    -    -   vpermilpd  $1,    %xmm0,
  36 ///  %xmm1
  37 ///  -    -    -    -   1.00  -    -    -    -    -   vaddps     %xmm0, %xmm1,
  38 ///  %xmm2
  39 ///  -    -    -    -    -   1.00  -    -    -    -   vmovshdup  %xmm2, %xmm3
  40 ///  -    -    -    -   1.00  -    -    -    -    -   vaddss     %xmm2, %xmm3,
  41 ///  %xmm4
  42 ///
  43 /// In this example, we have AVX code executed on AMD Jaguar (btver2).
  44 /// Both shuffles and vector floating point add operations on XMM registers have
  45 /// a reciprocal throughput of 1cy.
  46 /// Each add is issued to pipeline JFPU0, while each shuffle is issued to
  47 /// pipeline JFPU1. The overall pressure per iteration is reported by two
  48 /// tables: the first smaller table is the resource pressure per iteration;
  49 /// the second table reports resource pressure per instruction. Values are the
  50 /// average resource cycles consumed by an instruction.
  51 /// Every vector add from the example uses resource JFPU0 for an average of 1cy
  52 /// per iteration. Consequently, the resource pressure on JFPU0 is of 2cy per
  53 /// iteration.
  54 ///
  55 //===----------------------------------------------------------------------===//
  56
  57 #ifndef LLVM_TOOLS_LLVM_MCA_RESOURCEPRESSUREVIEW_H
  58 #define LLVM_TOOLS_LLVM_MCA_RESOURCEPRESSUREVIEW_H
  59
  60 #include "Views/View.h"
  61 #include "llvm/ADT/ArrayRef.h"
  62 #include "llvm/ADT/DenseMap.h"
  63 #include "llvm/MC/MCInst.h"
  64 #include "llvm/MC/MCInstPrinter.h"
  65 #include "llvm/MC/MCSubtargetInfo.h"
  66
  67 namespace llvm {
  68 namespace mca {
  69
  70 /// This class collects resource pressure statistics and it is able to print
  71 /// out all the collected information as a table to an output stream.
  72 class ResourcePressureView : public View {
  73   const llvm::MCSubtargetInfo &STI;
  74   llvm::MCInstPrinter &MCIP;
  75   llvm::ArrayRef<llvm::MCInst> Source;
  76   unsigned LastInstructionIdx;
  77
  78   // Map to quickly obtain the ResourceUsage column index from a processor
  79   // resource ID.
  80   llvm::DenseMap<unsigned, unsigned> Resource2VecIndex;
  81
  82   // Table of resources used by instructions.
  83   std::vector<ResourceCycles> ResourceUsage;
  84   unsigned NumResourceUnits;
  85
  86   void printResourcePressurePerIter(llvm::raw_ostream &OS) const;
  87   void printResourcePressurePerInst(llvm::raw_ostream &OS) const;
  88
  89 public:
  90   ResourcePressureView(const llvm::MCSubtargetInfo &sti,
  91                        llvm::MCInstPrinter &Printer,
  92                        llvm::ArrayRef<llvm::MCInst> S);
  93
  94   void onEvent(const HWInstructionEvent &Event) override;
  95   void printView(llvm::raw_ostream &OS) const override {
  96     printResourcePressurePerIter(OS);
  97     printResourcePressurePerInst(OS);
  98   }
  99 };
 100 } // namespace mca
 101 } // namespace llvm
 102
 103 #endif