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[llvm-mca][View] Improved Retire Control Unit Statistics.
RetireControlUnitStatistics now reports extra information about the ROB and the avg/maximum number of entries consumed over the entire simulation. Example: Retire Control Unit - number of cycles where we saw N instructions retired: [# retired], [# cycles] 0, 109 (17.9%) 1, 102 (16.7%) 2, 399 (65.4%) Total ROB Entries: 64 Max Used ROB Entries: 35 ( 54.7% ) Average Used ROB Entries per cy: 32 ( 50.0% ) Documentation in llvm/docs/CommandGuide/llvmn-mca.rst has been updated to reflect this change. llvm-svn: 347493
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‎llvm/docs/CommandGuide/llvm-mca.rst

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@@ -516,6 +516,10 @@ sections.
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1, 102 (16.7%)
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2, 399 (65.4%)
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Total ROB Entries: 64
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Max Used ROB Entries: 35 ( 54.7% )
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Average Used ROB Entries per cy: 32 ( 50.0% )
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Register File statistics:
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Total number of mappings created: 900

‎llvm/test/tools/llvm-mca/X86/BdVer2/rcu-statistics.s

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@@ -60,3 +60,7 @@
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# CHECK-NEXT: 1, 9 (40.9%)
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# CHECK-NEXT: 3, 1 (4.5%)
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# CHECK-NEXT: 4, 1 (4.5%)
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# CHECK: Total ROB Entries: 128
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# CHECK-NEXT: Max Used ROB Entries: 16 ( 12.5% )
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# CHECK-NEXT: Average Used ROB Entries per cy: 9 ( 7.0% )

‎llvm/test/tools/llvm-mca/X86/BtVer2/rcu-statistics.s

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@@ -58,3 +58,7 @@
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# CHECK-NEXT: [# retired], [# cycles]
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# CHECK-NEXT: 0, 23 (74.2%)
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# CHECK-NEXT: 2, 8 (25.8%)
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# CHECK: Total ROB Entries: 64
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# CHECK-NEXT: Max Used ROB Entries: 16 ( 25.0% )
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# CHECK-NEXT: Average Used ROB Entries per cy: 11 ( 17.2% )

‎llvm/test/tools/llvm-mca/X86/option-all-stats-1.s

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@@ -62,6 +62,10 @@ add %eax, %eax
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# FULLREPORT-NEXT: 0, 3 (2.9%)
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# FULLREPORT-NEXT: 1, 100 (97.1%)
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# FULLREPORT: Total ROB Entries: 64
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# FULLREPORT-NEXT: Max Used ROB Entries: 22 ( 34.4% )
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# FULLREPORT-NEXT: Average Used ROB Entries per cy: 17 ( 26.6% )
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# FULLREPORT: Register File statistics:
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# FULLREPORT-NEXT: Total number of mappings created: 200
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# FULLREPORT-NEXT: Max number of mappings used: 44

‎llvm/test/tools/llvm-mca/X86/option-all-stats-2.s

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@@ -63,6 +63,10 @@ add %eax, %eax
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# ALL-NEXT: 0, 3 (2.9%)
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# ALL-NEXT: 1, 100 (97.1%)
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# ALL: Total ROB Entries: 64
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# ALL-NEXT: Max Used ROB Entries: 22 ( 34.4% )
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# ALL-NEXT: Average Used ROB Entries per cy: 17 ( 26.6% )
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# ALL: Register File statistics:
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# ALL-NEXT: Total number of mappings created: 200
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# ALL-NEXT: Max number of mappings used: 44

‎llvm/test/tools/llvm-mca/X86/option-all-views-1.s

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@@ -64,6 +64,10 @@ add %eax, %eax
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# FULLREPORT-NEXT: 0, 3 (2.9%)
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# FULLREPORT-NEXT: 1, 100 (97.1%)
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# FULLREPORT: Total ROB Entries: 64
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# FULLREPORT-NEXT: Max Used ROB Entries: 22 ( 34.4% )
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# FULLREPORT-NEXT: Average Used ROB Entries per cy: 17 ( 26.6% )
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# FULLREPORT: Register File statistics:
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# FULLREPORT-NEXT: Total number of mappings created: 200
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# FULLREPORT-NEXT: Max number of mappings used: 44

‎llvm/test/tools/llvm-mca/X86/option-all-views-2.s

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@@ -63,6 +63,10 @@ add %eax, %eax
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# ALL-NEXT: 0, 3 (2.9%)
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# ALL-NEXT: 1, 100 (97.1%)
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# ALL: Total ROB Entries: 64
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# ALL-NEXT: Max Used ROB Entries: 22 ( 34.4% )
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# ALL-NEXT: Average Used ROB Entries per cy: 17 ( 26.6% )
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# ALL: Register File statistics:
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# ALL-NEXT: Total number of mappings created: 200
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# ALL-NEXT: Max number of mappings used: 44

‎llvm/tools/llvm-mca/Views/RetireControlUnitStatistics.cpp

Lines changed: 43 additions & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -18,9 +18,39 @@
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namespace llvm {
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namespace mca {
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RetireControlUnitStatistics::RetireControlUnitStatistics(const MCSchedModel &SM)
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: NumRetired(0), NumCycles(0), EntriesInUse(0), MaxUsedEntries(0),
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SumOfUsedEntries(0) {
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TotalROBEntries = SM.MicroOpBufferSize;
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if (SM.hasExtraProcessorInfo()) {
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const MCExtraProcessorInfo &EPI = SM.getExtraProcessorInfo();
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if (EPI.ReorderBufferSize)
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TotalROBEntries = EPI.ReorderBufferSize;
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}
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}
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void RetireControlUnitStatistics::onEvent(const HWInstructionEvent &Event) {
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if (Event.Type == HWInstructionEvent::Retired)
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if (Event.Type == HWInstructionEvent::Dispatched) {
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unsigned NumEntries =
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static_cast<const HWInstructionDispatchedEvent &>(Event).MicroOpcodes;
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EntriesInUse += NumEntries;
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}
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if (Event.Type == HWInstructionEvent::Retired) {
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unsigned ReleasedEntries = Event.IR.getInstruction()->getDesc().NumMicroOps;
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assert(EntriesInUse >= ReleasedEntries && "Invalid internal state!");
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EntriesInUse -= ReleasedEntries;
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++NumRetired;
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}
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}
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void RetireControlUnitStatistics::onCycleEnd() {
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// Update histogram
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RetiredPerCycle[NumRetired]++;
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NumRetired = 0;
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++NumCycles;
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MaxUsedEntries = std::max(MaxUsedEntries, EntriesInUse);
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SumOfUsedEntries += EntriesInUse;
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}
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void RetireControlUnitStatistics::printView(raw_ostream &OS) const {
@@ -41,6 +71,18 @@ void RetireControlUnitStatistics::printView(raw_ostream &OS) const {
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<< "%)\n";
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}
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unsigned AvgUsage = (double)SumOfUsedEntries / NumCycles;
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double MaxUsagePercentage = ((double)MaxUsedEntries / TotalROBEntries) * 100.0;
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double NormalizedMaxPercentage = floor((MaxUsagePercentage * 10) + 0.5) / 10;
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double AvgUsagePercentage = ((double)AvgUsage / TotalROBEntries) * 100.0;
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double NormalizedAvgPercentage = floor((AvgUsagePercentage * 10) + 0.5) / 10;
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TempStream << "\nTotal ROB Entries: " << TotalROBEntries
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<< "\nMax Used ROB Entries: " << MaxUsedEntries
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<< format(" ( %.1f%% )", NormalizedMaxPercentage)
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<< "\nAverage Used ROB Entries per cy: " << AvgUsage
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<< format(" ( %.1f%% )\n", NormalizedAvgPercentage);
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TempStream.flush();
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OS << Buffer;
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}

‎llvm/tools/llvm-mca/Views/RetireControlUnitStatistics.h

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@@ -16,18 +16,21 @@
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///
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/// Retire Control Unit - number of cycles where we saw N instructions retired:
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/// [# retired], [# cycles]
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/// 0, 9 (6.9%)
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/// 1, 6 (4.6%)
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/// 2, 1 (0.8%)
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/// 4, 3 (2.3%)
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/// 0, 109 (17.9%)
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/// 1, 102 (16.7%)
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/// 2, 399 (65.4%)
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///
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/// Total ROB Entries: 64
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/// Max Used ROB Entries: 35 ( 54.7% )
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/// Average Used ROB Entries per cy: 32 ( 50.0% )
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///
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_TOOLS_LLVM_MCA_RETIRECONTROLUNITSTATISTICS_H
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#define LLVM_TOOLS_LLVM_MCA_RETIRECONTROLUNITSTATISTICS_H
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#include "Views/View.h"
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#include "llvm/MC/MCSubtargetInfo.h"
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#include "llvm/MC/MCSchedule.h"
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#include <map>
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namespace llvm {
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unsigned NumRetired;
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unsigned NumCycles;
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void updateHistograms() {
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RetiredPerCycle[NumRetired]++;
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NumRetired = 0;
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}
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unsigned TotalROBEntries;
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unsigned EntriesInUse;
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unsigned MaxUsedEntries;
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unsigned SumOfUsedEntries;
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public:
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RetireControlUnitStatistics() : NumRetired(0), NumCycles(0) {}
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RetireControlUnitStatistics(const MCSchedModel &SM);
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void onEvent(const HWInstructionEvent &Event) override;
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void onCycleBegin() override { NumCycles++; }
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void onCycleEnd() override { updateHistograms(); }
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void onCycleEnd() override;
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void printView(llvm::raw_ostream &OS) const override;
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};
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} // namespace mca
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} // namespace llvm
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‎llvm/tools/llvm-mca/llvm-mca.cpp

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@@ -472,7 +472,7 @@ int main(int argc, char **argv) {
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Printer.addView(llvm::make_unique<mca::SchedulerStatistics>(*STI));
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if (PrintRetireStats)
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Printer.addView(llvm::make_unique<mca::RetireControlUnitStatistics>());
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Printer.addView(llvm::make_unique<mca::RetireControlUnitStatistics>(SM));
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if (PrintRegisterFileStats)
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Printer.addView(llvm::make_unique<mca::RegisterFileStatistics>(*STI));

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