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//===--------------------- DispatchStatistics.h -----------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
/// \file
///
/// This file implements a view that prints a few statistics related to the
/// dispatch logic. It collects and analyzes instruction dispatch events as
/// well as static/dynamic dispatch stall events.
///
/// 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
///
///
/// Dispatch Logic - number of cycles where we saw N micro opcodes dispatched:
/// [# dispatched], [# cycles]
/// 0, 15 (11.5%)
/// 2, 4 (3.1%)
///
//===----------------------------------------------------------------------===//
#ifndef LLVM_TOOLS_LLVM_MCA_DISPATCHVIEW_H
#define LLVM_TOOLS_LLVM_MCA_DISPATCHVIEW_H
#include "llvm/ADT/SmallVector.h"
#include "llvm/MC/MCSubtargetInfo.h"
#include "llvm/MCA/View.h"
#include <map>
namespace llvm {
namespace mca {
class DispatchStatistics : public View {
unsigned NumDispatched;
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;
using Histogram = std::map<unsigned, unsigned>;
Histogram DispatchGroupSizePerCycle;
void updateHistograms() {
DispatchGroupSizePerCycle[NumDispatched]++;
NumDispatched = 0;
}
void printDispatchHistogram(llvm::raw_ostream &OS) const;
void printDispatchStalls(llvm::raw_ostream &OS) const;
public:
DispatchStatistics()
: NumDispatched(0), NumCycles(0),
HWStalls(HWStallEvent::LastGenericEvent) {}
void onEvent(const HWStallEvent &Event) override;
void onEvent(const HWInstructionEvent &Event) override;
void onCycleBegin() override { NumCycles++; }
void onCycleEnd() override { updateHistograms(); }
void printView(llvm::raw_ostream &OS) const override {
printDispatchStalls(OS);
printDispatchHistogram(OS);
}
StringRef getNameAsString() const override { return "DispatchStatistics"; }
json::Value toJSON() const override;
};
} // namespace mca
} // namespace llvm
#endif
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