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//===--------------------- SchedulerStatistics.cpp --------------*- 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 the SchedulerStatistics interface.
///
//===----------------------------------------------------------------------===//
#include "Views/SchedulerStatistics.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/FormattedStream.h"
namespace llvm {
namespace mca {
SchedulerStatistics::SchedulerStatistics(const llvm::MCSubtargetInfo &STI)
: SM(STI.getSchedModel()), LQResourceID(0), SQResourceID(0), NumIssued(0),
NumCycles(0), MostRecentLoadDispatched(~0U),
MostRecentStoreDispatched(~0U),
Usage(STI.getSchedModel().NumProcResourceKinds, {0, 0, 0}) {
if (SM.hasExtraProcessorInfo()) {
const MCExtraProcessorInfo &EPI = SM.getExtraProcessorInfo();
LQResourceID = EPI.LoadQueueID;
SQResourceID = EPI.StoreQueueID;
}
}
// FIXME: This implementation works under the assumption that load/store queue
// entries are reserved at 'instruction dispatched' stage, and released at
// 'instruction executed' stage. This currently matches the behavior of LSUnit.
//
// The current design minimizes the number of events generated by the
// Dispatch/Execute stages, at the cost of doing extra bookkeeping in method
// `onEvent`. However, it introduces a subtle dependency between this view and
// how the LSUnit works.
//
// In future we should add a new "memory queue" event type, so that we stop
// making assumptions on how LSUnit internally works (See PR39828).
void SchedulerStatistics::onEvent(const HWInstructionEvent &Event) {
if (Event.Type == HWInstructionEvent::Issued) {
const Instruction &Inst = *Event.IR.getInstruction();
NumIssued += Inst.getDesc().NumMicroOps;
} else if (Event.Type == HWInstructionEvent::Dispatched) {
const Instruction &Inst = *Event.IR.getInstruction();
const unsigned Index = Event.IR.getSourceIndex();
if (LQResourceID && Inst.getMayLoad() &&
MostRecentLoadDispatched != Index) {
Usage[LQResourceID].SlotsInUse++;
MostRecentLoadDispatched = Index;
}
if (SQResourceID && Inst.getMayStore() &&
MostRecentStoreDispatched != Index) {
Usage[SQResourceID].SlotsInUse++;
MostRecentStoreDispatched = Index;
}
} else if (Event.Type == HWInstructionEvent::Executed) {
const Instruction &Inst = *Event.IR.getInstruction();
if (LQResourceID && Inst.getMayLoad()) {
assert(Usage[LQResourceID].SlotsInUse);
Usage[LQResourceID].SlotsInUse--;
}
if (SQResourceID && Inst.getMayStore()) {
assert(Usage[SQResourceID].SlotsInUse);
Usage[SQResourceID].SlotsInUse--;
}
}
}
void SchedulerStatistics::onReservedBuffers(const InstRef & /* unused */,
ArrayRef<unsigned> Buffers) {
for (const unsigned Buffer : Buffers) {
if (Buffer == LQResourceID || Buffer == SQResourceID)
continue;
Usage[Buffer].SlotsInUse++;
}
}
void SchedulerStatistics::onReleasedBuffers(const InstRef & /* unused */,
ArrayRef<unsigned> Buffers) {
for (const unsigned Buffer : Buffers) {
if (Buffer == LQResourceID || Buffer == SQResourceID)
continue;
Usage[Buffer].SlotsInUse--;
}
}
void SchedulerStatistics::updateHistograms() {
for (BufferUsage &BU : Usage) {
BU.CumulativeNumUsedSlots += BU.SlotsInUse;
BU.MaxUsedSlots = std::max(BU.MaxUsedSlots, BU.SlotsInUse);
}
IssueWidthPerCycle[NumIssued]++;
NumIssued = 0;
}
void SchedulerStatistics::printSchedulerStats(raw_ostream &OS) const {
OS << "\n\nSchedulers - "
<< "number of cycles where we saw N micro opcodes issued:\n";
OS << "[# issued], [# cycles]\n";
bool HasColors = OS.has_colors();
const auto It =
std::max_element(IssueWidthPerCycle.begin(), IssueWidthPerCycle.end());
for (const std::pair<const unsigned, unsigned> &Entry : IssueWidthPerCycle) {
unsigned NumIssued = Entry.first;
if (NumIssued == It->first && HasColors)
OS.changeColor(raw_ostream::SAVEDCOLOR, true, false);
unsigned IPC = Entry.second;
OS << " " << NumIssued << ", " << IPC << " ("
<< format("%.1f", ((double)IPC / NumCycles) * 100) << "%)\n";
if (HasColors)
OS.resetColor();
}
}
void SchedulerStatistics::printSchedulerUsage(raw_ostream &OS) const {
assert(NumCycles && "Unexpected number of cycles!");
OS << "\nScheduler's queue usage:\n";
if (all_of(Usage, [](const BufferUsage &BU) { return !BU.MaxUsedSlots; })) {
OS << "No scheduler resources used.\n";
return;
}
OS << "[1] Resource name.\n"
<< "[2] Average number of used buffer entries.\n"
<< "[3] Maximum number of used buffer entries.\n"
<< "[4] Total number of buffer entries.\n\n"
<< " [1] [2] [3] [4]\n";
formatted_raw_ostream FOS(OS);
bool HasColors = FOS.has_colors();
for (unsigned I = 0, E = SM.getNumProcResourceKinds(); I < E; ++I) {
const MCProcResourceDesc &ProcResource = *SM.getProcResource(I);
if (ProcResource.BufferSize <= 0)
continue;
const BufferUsage &BU = Usage[I];
double AvgUsage = (double)BU.CumulativeNumUsedSlots / NumCycles;
double AlmostFullThreshold = (double)(ProcResource.BufferSize * 4) / 5;
unsigned NormalizedAvg = floor((AvgUsage * 10) + 0.5) / 10;
unsigned NormalizedThreshold = floor((AlmostFullThreshold * 10) + 0.5) / 10;
FOS << ProcResource.Name;
FOS.PadToColumn(17);
if (HasColors && NormalizedAvg >= NormalizedThreshold)
FOS.changeColor(raw_ostream::YELLOW, true, false);
FOS << NormalizedAvg;
if (HasColors)
FOS.resetColor();
FOS.PadToColumn(28);
if (HasColors &&
BU.MaxUsedSlots == static_cast<unsigned>(ProcResource.BufferSize))
FOS.changeColor(raw_ostream::RED, true, false);
FOS << BU.MaxUsedSlots;
if (HasColors)
FOS.resetColor();
FOS.PadToColumn(39);
FOS << ProcResource.BufferSize << '\n';
}
FOS.flush();
}
void SchedulerStatistics::printView(raw_ostream &OS) const {
printSchedulerStats(OS);
printSchedulerUsage(OS);
}
} // namespace mca
} // namespace llvm
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