Ingredients

Application:
C++ STL/Boost* based sample.
Boost is a set of libraries for C++ that supports tasks and structures such as linear algebra, pseudorandom number generation, multithreading, and more.
In this example, Boost 1.77.0 for Windows* is used (download sources or binaries).
Performance analysis tool:
Intel® VTune™ Profiler 2021.9—Hotspots analysis
Operating system:
Microsoft Windows Server* 2016
IDE:
Microsoft Visual Studio* 2017
CPU:
Intel® Xeon® E5-2695 v3 (formerly codenamed Haswell)

Configure Project and Build Sample

#include <iostream>
#include <vector>
#include <chrono>
#include <thread>
#include <string_view>

#include <boost/algorithm/string.hpp>

using namespace std::chrono;

void generateRandomText(std::string& text, const size_t words, const size_t symbolsInWord)
{
	for (size_t i = 0; i < words; i++)
	{
		for (size_t j = 0; j < symbolsInWord; j++)
		{
			text += 'a' + i % 26;
		}
		text += ' ';
	}
}

void splitByWordsBoost(const std::string& text, std::vector<std::string>& splitWords)
{
	boost::split(splitWords, text, boost::is_any_of(" "));
}

void splitByWordsStdString(const std::string& text, std::vector<std::string>& splitWords)
{
	const char delimiter = ' ';
	size_t start, end = 0;
	while ((start = text.find_first_not_of(delimiter, end)) != std::string::npos) {
		end = text.find(delimiter, start);
		splitWords.push_back(text.substr(start, end - start));
	}
}

void splitByWordsStdStringView(const std::string& text, std::vector<std::string_view>& splitWords)
{
	const char delimiter = ' ';
	size_t start, end = 0;
	std::string_view textView(text);
	while ((start = textView.find_first_not_of(delimiter, end)) != std::string::npos) {
		end = textView.find(delimiter, start);
		splitWords.emplace_back(textView.substr(start, end - start));
	}
}

int main(int argc, char** argv)
{
	int splitMode = 0;
	const char* msg = "splitByWordsBoost";
	if (argc > 1)
	{
		switch (*argv[1])
		{
		case '2': splitMode = 1; msg = "splitByWordsStdString"; break;
		case '3': splitMode = 2; msg = "splitByWordsStdStringView"; break;
		case '4': splitMode = 3; msg = "splitByWordsStdStringView(pre-allocated vector)"; break;
		}
	}

	const size_t numOfWords = 100000000, symbolsInWord = 10;
	std::string text;
	text.reserve(numOfWords * (symbolsInWord+1));

	std::cout << "Generating random text: ";
	auto start = high_resolution_clock::now();
	generateRandomText(text, numOfWords, symbolsInWord);
	auto stop = high_resolution_clock::now();
	std::cout << duration_cast<duration<float>>(stop - start).count() << " seconds" << std::endl;

	std::vector<std::string> splitWords;
	std::vector<std::string_view> splitWordsView;
	if (splitMode == 3) splitWordsView.reserve(numOfWords);

	std::cout << msg << " function: ";
	std::thread thread;
	start = high_resolution_clock::now();
	switch (splitMode)
	{
	case 0: thread = std::thread(splitByWordsBoost, std::ref(text), std::ref(splitWords)); break;
	case 1: thread = std::thread(splitByWordsStdString, std::ref(text), std::ref(splitWords)); break;
	case 2:
	case 3: thread = std::thread(splitByWordsStdStringView, std::ref(text), std::ref(splitWordsView)); break;
	}
	thread.join();
	stop = high_resolution_clock::now();

	std::cout << duration_cast<duration<float>>(stop - start).count() << " seconds" << std::endl;
	auto splitWordsSize = splitMode >= 2 ? splitWordsView.size() : splitWords.size();
	std::cout << "Split words: " << splitWordsSize << std::endl;
}

Right-click on the project node in the
Solution Explorer
and select
Properties
.
In the
Project Property Pages
window, make sure the
Configuration
drop-down is set to
Release
and
Platform
is set to
x64
.
In the
VC++ Directories
page, add the root Boost directory to
Include Directories
.
In the
VC++ Directories
page, add the Boost libraries directory to
Library Directories
.
The default directory is:
<boost-root-directory>\libs
In the
C/C++ > Language
page, make sure the
C++ Language Standard
option is set to
ISO C++17 Standard (/std:c++17)
.
The configuration is now ready.

g++ -Wall -O2 -g -pthread -std=c++17 -l <path-to-boost-dir> ConsoleApplication1.cpp -o ConsoleApplication1

Establish Performance Baseline

Click the
New Project
button on the toolbar and specify a name for the new project, such as split_string.
Click
Create Project
.
The
Configure Analysis
window opens.
On the
WHERE
pane, select the
Local Host
target system.
On the
WHAT
pane, select the
Launch Application
mode.
In the
Application
textbox, provide the path to the built application binary.
On the
HOW
pane, select the
Hotspots
analysis.
Click
Start
to run the analysis.

Analyze Hotspots Result with Summary and Bottom-up Windows

Identify Hot Code Paths on the Flame Graph

Analyze Second Implementation

Analyze Third Implementation

Analyze Fourth Implementation

Summary