[brlcad-devel] comparing performance of bu_hash vs C++ map

[Daniel Roßberg]

I've looked into this task for some time and found it difficult to compare
them.   Attached is a version with integers as keys.  I haven't done real
tests with it yet.

Regards
    Daniel

//
//  main.cpp
//  test.cpp
//
//  Created by Lucas Prieels on 12/12/17.
//  Copyright © 2017 Lucas Prieels. All rights reserved.
//

#define ll long long

#include "bu.h"
#include "bu/hash.h"
#include <iostream>
#include <string>
#include <unordered_map>

using namespace std;


void addValueBu(bu_hash_tbl* tab, int nbr){
    int key = 0;

    for (int i=0; i<nbr; i++){
        bu_hash_set(tab, (const uint8_t *) &key, 4, NULL);
        key++;
    }
}

void addAndPopValueBu(bu_hash_tbl* tab, int nbr){
    int key = 0;

    for (int i=0; i<nbr; i++){
        bu_hash_set(tab, (const uint8_t *) &key, 4, NULL);
        bu_hash_rm(tab, (const uint8_t *) &key, 4);
        key++;
    }
}

void addAndRetrieveValueBu(bu_hash_tbl* tab, int nbr){
    int key = 0;

    for (int i=0; i<nbr; i++){
        bu_hash_set(tab, (const uint8_t *) &key, 4, NULL);
        char* t=(char *)bu_hash_get(tab, (const uint8_t *) &key, 4);
        key++;
    }
}

void bu_hash(int nb){
    bu_hash_tbl* tab=bu_hash_create(nb);
    cout << -1;
    ll int start = bu_gettime();
    addValueBu(tab, nb);
    ll int time2=bu_gettime();
    addAndPopValueBu(tab, nb);
    ll int time3=bu_gettime();
    addAndRetrieveValueBu(tab, nb);
    cout << "Time of execution for bu_hash: " << endl << "Adding " << nb << " values : " << time2-start << endl << "Adding and popping " << nb << " values : " << time3-time2 << endl << "Adding and retrieving " << nb << " values : " << bu_gettime()-time3 << endl << endl;
}

void addValueSTL(unordered_map<int, void*> &m, int nb){
    int key = 0;

    for (int i=0; i<nb; i++){
        m[key]=NULL;
        key++;
    }
}

void addAndPopValueSTL(unordered_map<int, void*> &m, int nb){
    int key = 0;

    for (int i=0; i<nb; i++){
        m[key]=NULL;
        m.erase(key);
        key++;
    }
}

void addAndRetrieveValueSTL(unordered_map<int, void*> &m, int nb){
    int key = 0;

    for (int i=0; i<nb; i++){
        m[key]=NULL;
        void* a=m[key];
        key++;
    }
}

void stl_map(int nb){
    unordered_map<int, void*> m;
    ll int start = bu_gettime();
    addValueSTL(m, nb);
    ll int time2=bu_gettime();
    addAndPopValueSTL(m, nb);
    ll int time3=bu_gettime();
    addAndRetrieveValueSTL(m, nb);
    cout << "Time of execution for STL map: " << endl << "Adding " << nb << " values : " << time2-start << endl << "Adding and popping " << nb << " values : " << time3-time2 << endl << "Adding and retrieving " << nb << " values : " << bu_gettime()-time3 << endl << endl;
}

int main(int ac, char *av[]) {
    int nb;
    cout << "How many values would you like to test? " << endl;
    cin >> nb;
    cout << -1;
    bu_hash(nb);
    stl_map(nb);
    return 0;
}

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