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c++performancegraph-theory

How to create/initialize custom objects in C++ the fastest way possible?


I have a function that creates a vector of Nodes and Edges from a vector of Profiles. Its working as intended, but this function is by far the slowest part of my full script. It takes around 150 milliseconds to run.

Machine(s): Linux PC:

intel i7-12700k, 128 GB DDR4 3200 MHz RAM, Ubuntu LTS 20.04

Windows (WSL2) Laptop:

Ryzen 9 6900HX, 16 DB DDR5 RAM, Ubuntu 22.04 LTS (8 GB DDR5 RAM)

Both using gcc compiler and CMake and std=C++17

My source file that is the base of my entire program:

#ifndef DEFINITIONS_H
#define DEFINITIONS_H

#include <string>
#include <vector>
#include <string_view>

#include <string>
#include <iostream>
#include <unordered_map>
#include <algorithm>
#include <utility>
#include <immintrin.h>
#include <chrono>

typedef std::string s;
typedef std::string_view stv;


struct Experience 
    {
        s from_date;
        s to_date;
        s position_title;
        float duration;
        s location;
        s institution_name;
        float salary;

        Experience(s from_date, s to_date, s position_title, float duration, s location, s institution_name, float salary)
            {
                this->from_date = from_date;
                this->to_date = to_date;
                this->position_title = position_title;
                this->duration = duration;
                this->location = location;
                this->institution_name = institution_name;
                this->salary = salary;
            }
        
        Experience()
            {
                this->from_date = "";
                this->to_date = "";
                this->position_title = "";
                this->duration = 0;
                this->location = "";
                this->institution_name = "";
                this->salary = 0;
            }
        
        friend std::ostream& operator<<(std::ostream& os, const Experience& e)
            {
                os << "from_date: " << e.from_date << std::endl;
                os << "to_date: " << e.to_date << std::endl;
                os << "position_title: " << e.position_title << std::endl;
                os << "duration: " << e.duration << std::endl;
                os << "location: " << e.location << std::endl;
                os << "institution_name: " << e.institution_name << std::endl;
                os << "salary: " << e.salary << std::endl;
                return os;
            }

    };
typedef std::vector<Experience> Experiences;

struct Profile
    {
        s linkedin_url;
        s name;
        Experiences experiences;
        std::vector<s> skills;

        Profile(s linkedin_url, s name, std::vector<s> skills, Experiences experiences)
            {
                this->linkedin_url = linkedin_url;
                this->name = name;
                this->skills = skills;
                this->experiences = experiences;
            }
        
        Profile()
            {
                this->linkedin_url = "";
                this->name = "";
                this->skills = {};
                this->experiences = {};
            }
        
        friend std::ostream& operator<<(std::ostream& os, const Profile& p)
            {
                os << "linkedin_url: " << p.linkedin_url << std::endl;
                os << "name: " << p.name << std::endl;
                os << "experiences: " << std::endl;
                for (auto e : p.experiences)
                    {
                        os << '\t' << e << std::endl;
                    }
                return os;
            }
    };

typedef std::vector<Profile> Profiles;

struct Node
    {
        s name;
        s position_title;
        s institution_name;
        s location;
        s industry;
        s linkedin_url;
        float duration;
        int company_size;
        float median_tenure;
        float salary;
        float headcount_growth;
        float current_experience_duration;

        Node(s t_name,s t_position_title, s t_institution_name, s t_location, s t_industry,s linkedin_url, float t_duration, float t_current_experience_duration, int t_company_size, float t_median_tenure, float t_salary, float t_headcount_growth )
            {
                this->name = t_name;
                this->position_title = t_position_title;
                this->institution_name = t_institution_name;
                this->location = t_location;
                this->industry = t_industry;
                this->linkedin_url = linkedin_url;
                this->duration = t_duration;
                this->current_experience_duration = t_current_experience_duration;
                this->company_size = t_company_size;
                this->median_tenure = t_median_tenure;
                this->salary = t_salary;
                this->headcount_growth = t_headcount_growth;
            }
        
        Node()
            {
                this->name = "";
                this->position_title = "";
                this->institution_name = "";
                this->location = "";
                this->industry = "";
                this->linkedin_url = "";
                this->duration = 0;
                this->current_experience_duration = 0;
                this->company_size = 0;
                this->median_tenure = 0;
                this->salary = 0;
                this->headcount_growth = 0;
            }

        bool operator==(const Node& other) const
            {
                if (this->name == other.name && this->position_title == other.position_title && this->institution_name == other.institution_name && this->location == other.location)
                    return true;
                else
                    return false;
            }
        
        friend std::ostream& operator<<(std::ostream& os, const Node& node)
            {
                os << "Name: " << node.name << std::endl;
                os << "Position Title: " << node.position_title << std::endl;
                os << "Institution Name: " << node.institution_name << std::endl;
                os << "Location: " << node.location << std::endl;
                os << "Industry: " << node.industry << std::endl;
                os << "Linkedin URL: " << node.linkedin_url << std::endl;
                os << "Duration: " << node.duration << std::endl;
                os << "Current Experience Duration "<< node.current_experience_duration << std::endl;
                os << "Company Size: " << node.company_size << std::endl;
                os << "Median Tenure: " << node.median_tenure << std::endl;
                os << "Salary: " << node.salary << std::endl;
                os << "Headcount Growth: " << node.headcount_growth << std::endl;
                return os;
            }
        
    };

typedef std::vector<Node> Nodes;


struct Edge
    {
        Node source;
        Node target;
        s linkedin_url;
        float duration;
        int company_size;
        float median_tenure;
        float salary;
        float headcount_growth;

        Edge(Node t_source, Node t_target)
            {
                
                this->source = t_source;
                this->target = t_target;
                this->linkedin_url = this->target.linkedin_url;
                this->duration = this->target.duration;
                this->company_size = this->target.company_size;
                this->median_tenure = this->target.median_tenure;
                this->salary = this->target.salary;
                this->headcount_growth = this->target.headcount_growth;
            }
        
        Edge()
            {
                this->source = Node();
                this->target = Node();
                this->linkedin_url = "";
                this->duration = 0;
                this->company_size = 0;
                this->median_tenure = 0;
                this->salary = 0;
                this->headcount_growth = 0;
            }
        
        bool operator==(const Edge& other) const
            {
                if (this->source == other.source && this->target == other.target)
                    return true;
                else
                    return false;
            }
        
        friend std::ostream& operator<<(std::ostream& os, const Edge& edge)
            {
                os << "Source: " << edge.source << std::endl;
                os << "Target: " << edge.target << std::endl;
                os << "Linkedin URL: " << edge.linkedin_url << std::endl;
                os << "Duration: " << edge.duration << std::endl;
                os << "Company Size: " << edge.company_size << std::endl;
                os << "Median Tenure: " << edge.median_tenure << std::endl;
                os << "Salary: " << edge.salary << std::endl;
                os << "Headcount Growth: " << edge.headcount_growth << std::endl;
                return os;
            }
    };


typedef std::vector<Edge> Edges;


struct Company
    {
        s name;
        s industry;
        float headcount_growth;
        float median_tenure;
        int company_size;

        Company(s name, s industry, float headcount_growth, float median_tenure, int company_size)
            {
                this->name = name;
                this->industry = industry;
                this->headcount_growth = headcount_growth;
                this->median_tenure = median_tenure;
                this->company_size = company_size;
            }
        
        Company()
            {
                this->name = "";
                this->industry = "";
                this->headcount_growth = 0;
                this->median_tenure = 0;
                this->company_size = 0;
            }
        
        bool operator==(const Company& other) const
            {
                if (this->name == other.name)
                    {
                        return true;
                    }
                else
                    {
                        return false;
                    }
            }
        
        friend std::ostream& operator<<(std::ostream& os, const Company& company)
            {
                os << "Name: " << company.name << std::endl;
                os << "Industry: " << company.industry << std::endl;
                os << "Headcount Growth: " << company.headcount_growth << std::endl;
                os << "Median Tenure: " << company.median_tenure << std::endl;
                os << "Company Size: " << company.company_size << std::endl;
                return os;
            }

    };

typedef std::vector<Company> Companies;

#endif // DEFINITIONS_H    

The profiles.h source file (have not included irrelevant code):

#ifndef PROFILES_H
#define PROFILES_H

#include "definitions.h"

std::pair<Nodes,Edges> create_edges_and_nodes_from_profiles(Profiles & profiles, Companies & companies );

#endif // PROFILES_H

The profiles.cpp file:

std::pair<Nodes,Edges> create_edges_and_nodes_from_profiles(Profiles & profiles, Companies & companies)
    {
        using namespace std::literals;

        Nodes nodes;
        Edges edges;
        nodes.reserve(40'000);
        edges.reserve(40'000);

        bool use_profile;


        std::unordered_map<s,float> company_name_median_tenure_map;
        std::unordered_map<s,float> company_name_headcount_growth_map;
        std::unordered_map<s,int> company_name_company_size_map;
        std::unordered_map<s,s> company_name_industry_map;

        float current_duration;
        float t_company_size, t_median_tenure, t_headcount_growth, t_duration, t_salary;
        s t_name, t_position_title, t_location, t_institution_name, t_industry;

        

        #ifdef MONITOR
            auto before_map_createion = std::chrono::high_resolution_clock::now();
        #endif  

        for (Company & company : companies)
            {
                
                company_name_median_tenure_map[company.name] = company.median_tenure;
                company_name_headcount_growth_map[company.name] = company.headcount_growth;
                company_name_company_size_map[company.name] = company.company_size;
                company_name_industry_map[company.name] = company.industry;

            }
        
        #ifdef MONITOR
            auto after_map_creation = std::chrono::high_resolution_clock::now();

            auto temp = std::chrono::duration_cast<std::chrono::milliseconds>(after_map_creation-before_map_createion).count();

            std::cout<<temp<<std::endl;
        #endif

        for (Profile & profile : profiles)
            {
                Nodes nodes_temp;
                nodes_temp.reserve(profile.experiences.size());
                current_duration = 0.0;
                use_profile = false;


                for (Experience & experience : profile.experiences)
                    {
                        
                        stv location = stv(experience.location);
                        
                        if (location.compare(""sv)!=0)
                            {
                                
                                //if (location.find("United Kingdom"sv)!=stv::npos)
                                    
                                t_name = profile.name;
                                t_position_title = experience.position_title;
                                t_location = experience.location;

                                
                                t_duration = experience.duration;
                                
                                
                                t_institution_name = experience.institution_name;
                                
                                t_company_size = company_name_company_size_map[t_institution_name];
                                t_median_tenure = company_name_median_tenure_map[t_institution_name];
                                t_headcount_growth = company_name_headcount_growth_map[t_institution_name];

                                
                                t_salary = experience.salary;


                                t_industry = company_name_industry_map[t_institution_name];
                                
                                Node node_obj = Node(std::move(t_name),
                                    std::move(t_position_title),
                                        std::move(t_institution_name),
                                            std::move(t_location),
                                                std::move(t_industry),
                                                    profile.linkedin_url,
                                                        t_duration,
                                                            current_duration,
                                                                t_company_size,
                                                                    t_median_tenure,
                                                                        t_salary,
                                                                            t_headcount_growth);
                                                        
                                
                                nodes_temp.push_back(std::move(node_obj));
                                
                                current_duration += t_duration;
                                    
                            }
                        
                    }
                
                for (Node & node : nodes_temp)
                    {
                        if (node.location.compare(""sv)!=0)
                        {
                            use_profile = true;
                            break;
                        }
                            
                    }
                
                if (!use_profile)
                    continue;
                
                current_duration = 0.0;

                for (Nodes::reverse_iterator rit=nodes_temp.rbegin();rit!=nodes_temp.rend();++rit)
                    {
                        rit->current_experience_duration = current_duration;
                        current_duration += rit->duration;
                    }
                
                if (nodes_temp.size()>1)
                    {
                        for (int i=0;i<nodes_temp.size()-1;i++)
                            {
                                //Edge edge = Edge(&nodes_temp[i+1],&nodes_temp[i]);
                                edges.emplace_back(std::move(nodes_temp[i+1]),std::move(nodes_temp[i]));

                            }
                    }
                
                for (auto & node : nodes_temp)
                    {
                        nodes.push_back(std::move(node));
                    }
            }

        return std::make_pair(std::move(nodes),std::move(edges));
    }

Now in my main driver:

#include "definitions.h"
#include "profiles.h"


int main()
  {
     // not shown (but assume this works and created the profile objects as shown in definitions.h)
     Profiles profiles = get_profiles(coll_profiles);
    // Make the same assumption as before 
     Companies companies = get_companies(coll_companies);

      #ifdef MONITOR
            
          auto before_creating_edges_and_nodes =  std::chrono::high_resolution_clock::now();
            
      #endif

        
        
      // Create nodes and edges from profiles and companies
      auto[nodes, edges] =  create_edges_and_nodes_from_profiles(profiles,companies);

      #ifdef MONITOR
          auto after_creating_edges_and_nodes =  std::chrono::high_resolution_clock::now();
          auto time_creating_edges_and_nodes = std::chrono::duration_cast<std::chrono::milliseconds>(after_creating_edges_and_nodes - before_creating_edges_and_nodes).count();

            
      #endif
      // lots of functions using Nodes and Edges 
      //...
      //...
      return 0;
  }

Note that I am not an expert in C++. The code shown above works but it takes a significant amount of time (~150 milliseconds). The rest of the script combined (around 15 functions) takes less than 100 milliseconds.

My question is basically, how do I restructure the data and/or the initialization of the objects so that it is as fast as possible.

The reason I am asking is because, I found it impossible to find how to do this on Google. It could be because I don't know the right terminology.


Solution

  • Replace

        std::unordered_map<s,float> company_name_median_tenure_map;
        std::unordered_map<s,float> company_name_headcount_growth_map;
        std::unordered_map<s,int> company_name_company_size_map;
        std::unordered_map<s,s> company_name_industry_map;
    

    with

    struct company_data
    {
    float tenure;
    float growth;
    int size
    std:string industry;      // this should be an index into a table of industry names
    };
    
    std::unordered_map<std::string,company_data>  company_map;