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//===--------------------- BackendStatistics.h ------------------*- C++ -*-===//
//
// The LLVM Compiler Infrastructure
//
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
/// \file
///
/// This file implements a printer class for printing generic Backend
/// statistics related to the dispatch logic, scheduler and retire unit.
///
/// Example:
/// ========
///
/// Dynamic Dispatch Stall Cycles:
/// RAT - Register unavailable: 0
/// RCU - Retire tokens unavailable: 0
/// SCHEDQ - Scheduler full: 42
/// LQ - Load queue full: 0
/// SQ - Store queue full: 0
/// GROUP - Static restrictions on the dispatch group: 0
///
///
/// Register Alias Table:
/// Total number of mappings created: 210
/// Max number of mappings used: 35
///
///
/// Dispatch Logic - number of cycles where we saw N instructions dispatched:
/// [# dispatched], [# cycles]
/// 0, 15 (11.5%)
/// 5, 4 (3.1%)
///
/// Schedulers - number of cycles where we saw N instructions issued:
/// [# issued], [# cycles]
/// 0, 7 (5.4%)
/// 1, 4 (3.1%)
/// 2, 8 (6.2%)
///
/// Retire Control Unit - number of cycles where we saw N instructions retired:
/// [# retired], [# cycles]
/// 0, 9 (6.9%)
/// 1, 6 (4.6%)
/// 2, 1 (0.8%)
/// 4, 3 (2.3%)
///
///
/// Scheduler's queue usage:
/// JALU01, 0/20
/// JFPU01, 18/18
/// JLSAGU, 0/12
///
//===----------------------------------------------------------------------===//
#ifndef LLVM_TOOLS_LLVM_MCA_BACKENDSTATISTICS_H
#define LLVM_TOOLS_LLVM_MCA_BACKENDSTATISTICS_H
#include "Backend.h"
#include "View.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/Support/raw_ostream.h"
#include <map>
namespace mca {
class BackendStatistics : public View {
// TODO: remove the dependency from Backend.
const Backend &B;
const llvm::MCSubtargetInfo &STI;
using Histogram = std::map<unsigned, unsigned>;
Histogram DispatchGroupSizePerCycle;
Histogram RetiredPerCycle;
Histogram IssuedPerCycle;
unsigned NumDispatched;
unsigned NumIssued;
unsigned NumRetired;
unsigned NumCycles;
// Counts dispatch stall events caused by unavailability of resources. There
// is one counter for every generic stall kind (see class HWStallEvent).
llvm::SmallVector<unsigned, 8> HWStalls;
// Tracks the usage of a scheduler's queue.
struct BufferUsage {
unsigned SlotsInUse;
unsigned MaxUsedSlots;
};
// There is a map entry for each buffered resource in the scheduling model.
// Every time a buffer is consumed/freed, this view updates the corresponding
// entry.
llvm::DenseMap<unsigned, BufferUsage> BufferedResources;
void updateHistograms() {
DispatchGroupSizePerCycle[NumDispatched]++;
IssuedPerCycle[NumIssued]++;
RetiredPerCycle[NumRetired]++;
NumDispatched = 0;
NumIssued = 0;
NumRetired = 0;
}
void printRetireUnitStatistics(llvm::raw_ostream &OS) const;
void printDispatchUnitStatistics(llvm::raw_ostream &OS) const;
void printSchedulerStatistics(llvm::raw_ostream &OS) const;
void printDispatchStalls(llvm::raw_ostream &OS) const;
void printRATStatistics(llvm::raw_ostream &OS, unsigned Mappings,
unsigned MaxUsedMappings) const;
void printRCUStatistics(llvm::raw_ostream &OS, const Histogram &Histogram,
unsigned Cycles) const;
void printDispatchUnitUsage(llvm::raw_ostream &OS, const Histogram &Stats,
unsigned Cycles) const;
void printIssuePerCycle(const Histogram &IssuePerCycle,
unsigned TotalCycles) const;
void printSchedulerUsage(llvm::raw_ostream &OS,
const llvm::MCSchedModel &SM) const;
public:
BackendStatistics(const Backend &backend, const llvm::MCSubtargetInfo &sti)
: B(backend), STI(sti), NumDispatched(0), NumIssued(0), NumRetired(0),
NumCycles(0), HWStalls(HWStallEvent::LastGenericEvent) {}
void onInstructionEvent(const HWInstructionEvent &Event) override;
void onCycleBegin(unsigned Cycle) override { NumCycles++; }
void onCycleEnd(unsigned Cycle) override { updateHistograms(); }
void onStallEvent(const HWStallEvent &Event) override {
if (Event.Type < HWStallEvent::LastGenericEvent)
HWStalls[Event.Type]++;
}
// Increases the number of used scheduler queue slots of every buffered
// resource in the Buffers set.
void onReservedBuffers(llvm::ArrayRef<unsigned> Buffers) override;
// Decreases by one the number of used scheduler queue slots of every
// buffered resource in the Buffers set.
void onReleasedBuffers(llvm::ArrayRef<unsigned> Buffers) override;
void printView(llvm::raw_ostream &OS) const override {
printDispatchStalls(OS);
printRATStatistics(OS, B.getTotalRegisterMappingsCreated(),
B.getMaxUsedRegisterMappings());
printDispatchUnitStatistics(OS);
printSchedulerStatistics(OS);
printRetireUnitStatistics(OS);
printSchedulerUsage(OS, STI.getSchedModel());
}
};
} // namespace mca
#endif
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