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llvm-mirror/tools/llvm-cov/CoverageReport.cpp
Alexandre Ganea ae05eb086d [Support] On Windows, ensure hardware_concurrency() extends to all CPU sockets and all NUMA groups
The goal of this patch is to maximize CPU utilization on multi-socket or high core count systems, so that parallel computations such as LLD/ThinLTO can use all hardware threads in the system. Before this patch, on Windows, a maximum of 64 hardware threads could be used at most, in some cases dispatched only on one CPU socket.

== Background ==
Windows doesn't have a flat cpu_set_t like Linux. Instead, it projects hardware CPUs (or NUMA nodes) to applications through a concept of "processor groups". A "processor" is the smallest unit of execution on a CPU, that is, an hyper-thread if SMT is active; a core otherwise. There's a limit of 32-bit processors on older 32-bit versions of Windows, which later was raised to 64-processors with 64-bit versions of Windows. This limit comes from the affinity mask, which historically is represented by the sizeof(void*). Consequently, the concept of "processor groups" was introduced for dealing with systems with more than 64 hyper-threads.

By default, the Windows OS assigns only one "processor group" to each starting application, in a round-robin manner. If the application wants to use more processors, it needs to programmatically enable it, by assigning threads to other "processor groups". This also means that affinity cannot cross "processor group" boundaries; one can only specify a "preferred" group on start-up, but the application is free to allocate more groups if it wants to.

This creates a peculiar situation, where newer CPUs like the AMD EPYC 7702P (64-cores, 128-hyperthreads) are projected by the OS as two (2) "processor groups". This means that by default, an application can only use half of the cores. This situation could only get worse in the years to come, as dies with more cores will appear on the market.

== The problem ==
The heavyweight_hardware_concurrency() API was introduced so that only *one hardware thread per core* was used. Once that API returns, that original intention is lost, only the number of threads is retained. Consider a situation, on Windows, where the system has 2 CPU sockets, 18 cores each, each core having 2 hyper-threads, for a total of 72 hyper-threads. Both heavyweight_hardware_concurrency() and hardware_concurrency() currently return 36, because on Windows they are simply wrappers over std:🧵:hardware_concurrency() -- which can only return processors from the current "processor group".

== The changes in this patch ==
To solve this situation, we capture (and retain) the initial intention until the point of usage, through a new ThreadPoolStrategy class. The number of threads to use is deferred as late as possible, until the moment where the std::threads are created (ThreadPool in the case of ThinLTO).

When using hardware_concurrency(), setting ThreadCount to 0 now means to use all the possible hardware CPU (SMT) threads. Providing a ThreadCount above to the maximum number of threads will have no effect, the maximum will be used instead.
The heavyweight_hardware_concurrency() is similar to hardware_concurrency(), except that only one thread per hardware *core* will be used.

When LLVM_ENABLE_THREADS is OFF, the threading APIs will always return 1, to ensure any caller loops will be exercised at least once.

Differential Revision: https://reviews.llvm.org/D71775
2020-02-14 10:24:22 -05:00

447 lines
16 KiB
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//===- CoverageReport.cpp - Code coverage report -------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
//
// This class implements rendering of a code coverage report.
//
//===----------------------------------------------------------------------===//
#include "CoverageReport.h"
#include "RenderingSupport.h"
#include "llvm/ADT/DenseMap.h"
#include "llvm/Support/Format.h"
#include "llvm/Support/Path.h"
#include "llvm/Support/ThreadPool.h"
#include "llvm/Support/Threading.h"
#include <numeric>
using namespace llvm;
namespace {
/// Helper struct which prints trimmed and aligned columns.
struct Column {
enum TrimKind { NoTrim, WidthTrim, RightTrim };
enum AlignmentKind { LeftAlignment, RightAlignment };
StringRef Str;
unsigned Width;
TrimKind Trim;
AlignmentKind Alignment;
Column(StringRef Str, unsigned Width)
: Str(Str), Width(Width), Trim(WidthTrim), Alignment(LeftAlignment) {}
Column &set(TrimKind Value) {
Trim = Value;
return *this;
}
Column &set(AlignmentKind Value) {
Alignment = Value;
return *this;
}
void render(raw_ostream &OS) const {
if (Str.size() <= Width) {
if (Alignment == RightAlignment) {
OS.indent(Width - Str.size());
OS << Str;
return;
}
OS << Str;
OS.indent(Width - Str.size());
return;
}
switch (Trim) {
case NoTrim:
OS << Str;
break;
case WidthTrim:
OS << Str.substr(0, Width);
break;
case RightTrim:
OS << Str.substr(0, Width - 3) << "...";
break;
}
}
};
raw_ostream &operator<<(raw_ostream &OS, const Column &Value) {
Value.render(OS);
return OS;
}
Column column(StringRef Str, unsigned Width) { return Column(Str, Width); }
template <typename T>
Column column(StringRef Str, unsigned Width, const T &Value) {
return Column(Str, Width).set(Value);
}
// Specify the default column widths.
size_t FileReportColumns[] = {25, 12, 18, 10, 12, 18, 10,
16, 16, 10, 12, 18, 10};
size_t FunctionReportColumns[] = {25, 10, 8, 8, 10, 8, 8};
/// Adjust column widths to fit long file paths and function names.
void adjustColumnWidths(ArrayRef<StringRef> Files,
ArrayRef<StringRef> Functions) {
for (StringRef Filename : Files)
FileReportColumns[0] = std::max(FileReportColumns[0], Filename.size());
for (StringRef Funcname : Functions)
FunctionReportColumns[0] =
std::max(FunctionReportColumns[0], Funcname.size());
}
/// Prints a horizontal divider long enough to cover the given column
/// widths.
void renderDivider(ArrayRef<size_t> ColumnWidths, raw_ostream &OS) {
size_t Length = std::accumulate(ColumnWidths.begin(), ColumnWidths.end(), 0);
for (size_t I = 0; I < Length; ++I)
OS << '-';
}
/// Return the color which correponds to the coverage percentage of a
/// certain metric.
template <typename T>
raw_ostream::Colors determineCoveragePercentageColor(const T &Info) {
if (Info.isFullyCovered())
return raw_ostream::GREEN;
return Info.getPercentCovered() >= 80.0 ? raw_ostream::YELLOW
: raw_ostream::RED;
}
/// Get the number of redundant path components in each path in \p Paths.
unsigned getNumRedundantPathComponents(ArrayRef<std::string> Paths) {
// To start, set the number of redundant path components to the maximum
// possible value.
SmallVector<StringRef, 8> FirstPathComponents{sys::path::begin(Paths[0]),
sys::path::end(Paths[0])};
unsigned NumRedundant = FirstPathComponents.size();
for (unsigned I = 1, E = Paths.size(); NumRedundant > 0 && I < E; ++I) {
StringRef Path = Paths[I];
for (const auto &Component :
enumerate(make_range(sys::path::begin(Path), sys::path::end(Path)))) {
// Do not increase the number of redundant components: that would remove
// useful parts of already-visited paths.
if (Component.index() >= NumRedundant)
break;
// Lower the number of redundant components when there's a mismatch
// between the first path, and the path under consideration.
if (FirstPathComponents[Component.index()] != Component.value()) {
NumRedundant = Component.index();
break;
}
}
}
return NumRedundant;
}
/// Determine the length of the longest redundant prefix of the paths in
/// \p Paths.
unsigned getRedundantPrefixLen(ArrayRef<std::string> Paths) {
// If there's at most one path, no path components are redundant.
if (Paths.size() <= 1)
return 0;
unsigned PrefixLen = 0;
unsigned NumRedundant = getNumRedundantPathComponents(Paths);
auto Component = sys::path::begin(Paths[0]);
for (unsigned I = 0; I < NumRedundant; ++I) {
auto LastComponent = Component;
++Component;
PrefixLen += Component - LastComponent;
}
return PrefixLen;
}
} // end anonymous namespace
namespace llvm {
void CoverageReport::render(const FileCoverageSummary &File,
raw_ostream &OS) const {
auto FileCoverageColor =
determineCoveragePercentageColor(File.RegionCoverage);
auto FuncCoverageColor =
determineCoveragePercentageColor(File.FunctionCoverage);
auto InstantiationCoverageColor =
determineCoveragePercentageColor(File.InstantiationCoverage);
auto LineCoverageColor = determineCoveragePercentageColor(File.LineCoverage);
SmallString<256> FileName = File.Name;
sys::path::remove_dots(FileName, /*remove_dot_dots=*/true);
sys::path::native(FileName);
OS << column(FileName, FileReportColumns[0], Column::NoTrim);
if (Options.ShowRegionSummary) {
OS << format("%*u", FileReportColumns[1],
(unsigned)File.RegionCoverage.getNumRegions());
Options.colored_ostream(OS, FileCoverageColor)
<< format("%*u", FileReportColumns[2],
(unsigned)(File.RegionCoverage.getNumRegions() -
File.RegionCoverage.getCovered()));
if (File.RegionCoverage.getNumRegions())
Options.colored_ostream(OS, FileCoverageColor)
<< format("%*.2f", FileReportColumns[3] - 1,
File.RegionCoverage.getPercentCovered())
<< '%';
else
OS << column("-", FileReportColumns[3], Column::RightAlignment);
}
OS << format("%*u", FileReportColumns[4],
(unsigned)File.FunctionCoverage.getNumFunctions());
OS << format("%*u", FileReportColumns[5],
(unsigned)(File.FunctionCoverage.getNumFunctions() -
File.FunctionCoverage.getExecuted()));
if (File.FunctionCoverage.getNumFunctions())
Options.colored_ostream(OS, FuncCoverageColor)
<< format("%*.2f", FileReportColumns[6] - 1,
File.FunctionCoverage.getPercentCovered())
<< '%';
else
OS << column("-", FileReportColumns[6], Column::RightAlignment);
if (Options.ShowInstantiationSummary) {
OS << format("%*u", FileReportColumns[7],
(unsigned)File.InstantiationCoverage.getNumFunctions());
OS << format("%*u", FileReportColumns[8],
(unsigned)(File.InstantiationCoverage.getNumFunctions() -
File.InstantiationCoverage.getExecuted()));
if (File.InstantiationCoverage.getNumFunctions())
Options.colored_ostream(OS, InstantiationCoverageColor)
<< format("%*.2f", FileReportColumns[9] - 1,
File.InstantiationCoverage.getPercentCovered())
<< '%';
else
OS << column("-", FileReportColumns[9], Column::RightAlignment);
}
OS << format("%*u", FileReportColumns[10],
(unsigned)File.LineCoverage.getNumLines());
Options.colored_ostream(OS, LineCoverageColor) << format(
"%*u", FileReportColumns[11], (unsigned)(File.LineCoverage.getNumLines() -
File.LineCoverage.getCovered()));
if (File.LineCoverage.getNumLines())
Options.colored_ostream(OS, LineCoverageColor)
<< format("%*.2f", FileReportColumns[12] - 1,
File.LineCoverage.getPercentCovered())
<< '%';
else
OS << column("-", FileReportColumns[12], Column::RightAlignment);
OS << "\n";
}
void CoverageReport::render(const FunctionCoverageSummary &Function,
const DemangleCache &DC,
raw_ostream &OS) const {
auto FuncCoverageColor =
determineCoveragePercentageColor(Function.RegionCoverage);
auto LineCoverageColor =
determineCoveragePercentageColor(Function.LineCoverage);
OS << column(DC.demangle(Function.Name), FunctionReportColumns[0],
Column::RightTrim)
<< format("%*u", FunctionReportColumns[1],
(unsigned)Function.RegionCoverage.getNumRegions());
Options.colored_ostream(OS, FuncCoverageColor)
<< format("%*u", FunctionReportColumns[2],
(unsigned)(Function.RegionCoverage.getNumRegions() -
Function.RegionCoverage.getCovered()));
Options.colored_ostream(
OS, determineCoveragePercentageColor(Function.RegionCoverage))
<< format("%*.2f", FunctionReportColumns[3] - 1,
Function.RegionCoverage.getPercentCovered())
<< '%';
OS << format("%*u", FunctionReportColumns[4],
(unsigned)Function.LineCoverage.getNumLines());
Options.colored_ostream(OS, LineCoverageColor)
<< format("%*u", FunctionReportColumns[5],
(unsigned)(Function.LineCoverage.getNumLines() -
Function.LineCoverage.getCovered()));
Options.colored_ostream(
OS, determineCoveragePercentageColor(Function.LineCoverage))
<< format("%*.2f", FunctionReportColumns[6] - 1,
Function.LineCoverage.getPercentCovered())
<< '%';
OS << "\n";
}
void CoverageReport::renderFunctionReports(ArrayRef<std::string> Files,
const DemangleCache &DC,
raw_ostream &OS) {
bool isFirst = true;
for (StringRef Filename : Files) {
auto Functions = Coverage.getCoveredFunctions(Filename);
if (isFirst)
isFirst = false;
else
OS << "\n";
std::vector<StringRef> Funcnames;
for (const auto &F : Functions)
Funcnames.emplace_back(DC.demangle(F.Name));
adjustColumnWidths({}, Funcnames);
OS << "File '" << Filename << "':\n";
OS << column("Name", FunctionReportColumns[0])
<< column("Regions", FunctionReportColumns[1], Column::RightAlignment)
<< column("Miss", FunctionReportColumns[2], Column::RightAlignment)
<< column("Cover", FunctionReportColumns[3], Column::RightAlignment)
<< column("Lines", FunctionReportColumns[4], Column::RightAlignment)
<< column("Miss", FunctionReportColumns[5], Column::RightAlignment)
<< column("Cover", FunctionReportColumns[6], Column::RightAlignment);
OS << "\n";
renderDivider(FunctionReportColumns, OS);
OS << "\n";
FunctionCoverageSummary Totals("TOTAL");
for (const auto &F : Functions) {
auto Function = FunctionCoverageSummary::get(Coverage, F);
++Totals.ExecutionCount;
Totals.RegionCoverage += Function.RegionCoverage;
Totals.LineCoverage += Function.LineCoverage;
render(Function, DC, OS);
}
if (Totals.ExecutionCount) {
renderDivider(FunctionReportColumns, OS);
OS << "\n";
render(Totals, DC, OS);
}
}
}
void CoverageReport::prepareSingleFileReport(const StringRef Filename,
const coverage::CoverageMapping *Coverage,
const CoverageViewOptions &Options, const unsigned LCP,
FileCoverageSummary *FileReport, const CoverageFilter *Filters) {
for (const auto &Group : Coverage->getInstantiationGroups(Filename)) {
std::vector<FunctionCoverageSummary> InstantiationSummaries;
for (const coverage::FunctionRecord *F : Group.getInstantiations()) {
if (!Filters->matches(*Coverage, *F))
continue;
auto InstantiationSummary = FunctionCoverageSummary::get(*Coverage, *F);
FileReport->addInstantiation(InstantiationSummary);
InstantiationSummaries.push_back(InstantiationSummary);
}
if (InstantiationSummaries.empty())
continue;
auto GroupSummary =
FunctionCoverageSummary::get(Group, InstantiationSummaries);
if (Options.Debug)
outs() << "InstantiationGroup: " << GroupSummary.Name << " with "
<< "size = " << Group.size() << "\n";
FileReport->addFunction(GroupSummary);
}
}
std::vector<FileCoverageSummary> CoverageReport::prepareFileReports(
const coverage::CoverageMapping &Coverage, FileCoverageSummary &Totals,
ArrayRef<std::string> Files, const CoverageViewOptions &Options,
const CoverageFilter &Filters) {
unsigned LCP = getRedundantPrefixLen(Files);
auto NumThreads = Options.NumThreads;
// If NumThreads is not specified, auto-detect a good default.
if (NumThreads == 0)
NumThreads = Files.size();
ThreadPool Pool(heavyweight_hardware_concurrency(NumThreads));
std::vector<FileCoverageSummary> FileReports;
FileReports.reserve(Files.size());
for (StringRef Filename : Files) {
FileReports.emplace_back(Filename.drop_front(LCP));
Pool.async(&CoverageReport::prepareSingleFileReport, Filename,
&Coverage, Options, LCP, &FileReports.back(), &Filters);
}
Pool.wait();
for (const auto &FileReport : FileReports)
Totals += FileReport;
return FileReports;
}
void CoverageReport::renderFileReports(
raw_ostream &OS, const CoverageFilters &IgnoreFilenameFilters) const {
std::vector<std::string> UniqueSourceFiles;
for (StringRef SF : Coverage.getUniqueSourceFiles()) {
// Apply ignore source files filters.
if (!IgnoreFilenameFilters.matchesFilename(SF))
UniqueSourceFiles.emplace_back(SF.str());
}
renderFileReports(OS, UniqueSourceFiles);
}
void CoverageReport::renderFileReports(
raw_ostream &OS, ArrayRef<std::string> Files) const {
renderFileReports(OS, Files, CoverageFiltersMatchAll());
}
void CoverageReport::renderFileReports(
raw_ostream &OS, ArrayRef<std::string> Files,
const CoverageFiltersMatchAll &Filters) const {
FileCoverageSummary Totals("TOTAL");
auto FileReports =
prepareFileReports(Coverage, Totals, Files, Options, Filters);
std::vector<StringRef> Filenames;
for (const FileCoverageSummary &FCS : FileReports)
Filenames.emplace_back(FCS.Name);
adjustColumnWidths(Filenames, {});
OS << column("Filename", FileReportColumns[0]);
if (Options.ShowRegionSummary)
OS << column("Regions", FileReportColumns[1], Column::RightAlignment)
<< column("Missed Regions", FileReportColumns[2], Column::RightAlignment)
<< column("Cover", FileReportColumns[3], Column::RightAlignment);
OS << column("Functions", FileReportColumns[4], Column::RightAlignment)
<< column("Missed Functions", FileReportColumns[5], Column::RightAlignment)
<< column("Executed", FileReportColumns[6], Column::RightAlignment);
if (Options.ShowInstantiationSummary)
OS << column("Instantiations", FileReportColumns[7], Column::RightAlignment)
<< column("Missed Insts.", FileReportColumns[8], Column::RightAlignment)
<< column("Executed", FileReportColumns[9], Column::RightAlignment);
OS << column("Lines", FileReportColumns[10], Column::RightAlignment)
<< column("Missed Lines", FileReportColumns[11], Column::RightAlignment)
<< column("Cover", FileReportColumns[12], Column::RightAlignment) << "\n";
renderDivider(FileReportColumns, OS);
OS << "\n";
bool EmptyFiles = false;
for (const FileCoverageSummary &FCS : FileReports) {
if (FCS.FunctionCoverage.getNumFunctions())
render(FCS, OS);
else
EmptyFiles = true;
}
if (EmptyFiles && Filters.empty()) {
OS << "\n"
<< "Files which contain no functions:\n";
for (const FileCoverageSummary &FCS : FileReports)
if (!FCS.FunctionCoverage.getNumFunctions())
render(FCS, OS);
}
renderDivider(FileReportColumns, OS);
OS << "\n";
render(Totals, OS);
}
} // end namespace llvm