benchmark.cpp

#include <sys/time.h>
#include <iostream>
#include <fstream>
#include <cstdlib>
#include <stdint.h>
#include <string>
#include <cstring>
#include <vector>
#ifndef XXH3
#include "wyhash.h"
#else
#include "../xxHash/xxh3.h"
#endif

using namespace std;

struct ha
{
    size_t operator()(const string &s, uint64_t seed)const
    {
        #ifndef XXH3
        return wyhash(s.c_str(),s.size(),seed,_wyp);
        #else
        return XXH3_64bits_withSeed(s.c_str(),s.size(),seed);
        #endif
    }
};

vector <string> v;
template <class Hasher>
uint64_t bench_hash(const char *name)
{
    Hasher h;
    string s;
    timeval beg, end;
    uint64_t dummy=0;
    const uint64_t N=v.size(), R=0x1000;

    cerr.precision(2);
    cerr.setf(ios::fixed);
    cerr<<'|'<<name<<(strlen(name)<8?"\t\t|":"\t|");

    gettimeofday(&beg,NULL);
    for(size_t r=0; r<R; r++)
        for(size_t i=0; i<N; i++)
            dummy+=h(v[i],r);
    gettimeofday(&end,NULL);
    cerr<<1e-6*R*N/(end.tv_sec-beg.tv_sec+1e-6*(end.tv_usec-beg.tv_usec))<<"\t\t|";

    s.resize(1<<8);
    gettimeofday(&beg,NULL);
    for(size_t r=0; r<(R<<14); r++)
        dummy+=h(s,r);
    gettimeofday(&end,NULL);
    cerr<<1e-9*(R<<14)*s.size()/(end.tv_sec-beg.tv_sec+1e-6*(end.tv_usec-beg.tv_usec))<<"\t\t|";

    s.resize(1<<16);
    gettimeofday(&beg,NULL);
    for(size_t r=0; r<(R<<6); r++)
        dummy+=h(s,r);
    gettimeofday(&end,NULL);
    cerr<<1e-9*(R<<6)*s.size()/(end.tv_sec-beg.tv_sec+1e-6*(end.tv_usec-beg.tv_usec))<<"\t\t|\n";
    return dummy;
}

int main(int argc, char **argv)
{
    string file_name="/usr/share/dict/words", help_s="-h", s;
    if(argc>1)
    {
        if(help_s.compare(argv[1])==0)
        {
            cout<<"usage:\n"<<argv[0]<<" <file>\n";
            cout<<"if no arguments given \'"<<file_name<<"\' is used\n";
            return 0;
        }
        file_name=argv[1];
    }
    ifstream fi(file_name.c_str());
    if(fi.fail())
    {
        cout<<"File \'"<<file_name<<"\' not found.\n";
        cout<<"Try `-h\' for help.\n";
        return 1;
    }
    for(fi>>s; !fi.eof(); fi>>s)
        if(s.size())
            v.push_back(s);
    fi.close();
    //shuffle the array to benchmark random access
    for(size_t i=v.size()-1; i; i--)
        swap(v[i],v[rand()%(i+1)]);

    uint64_t r=0;
    cerr<<file_name<<'\n';
    cerr<<"|hash function\t|short hash/us\t|bulk_256B GB/s\t|bulk_64KB GB/s\t|\n";
    cerr<<"|----\t\t|----\t\t|----\t\t|----\t\t|\n";

    #ifndef XXH3
    r+=bench_hash<ha>("wyhash");
    #else
    r+=bench_hash<ha>("xxh3");
    #endif

    return r;
}