Profiling.h

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   /*************************************************************************************
 
    Grid physics library, www.github.com/paboyle/Grid 
 
    Source file: ./lib/util/Profiling.h
 
    Copyright (C) 2018
 
    Author: Guido Cossu <guido.cossu@ed.ac.uk>
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.
 
    This program is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.
 
    You should have received a copy of the GNU General Public License along
    with this program; if not, write to the Free Software Foundation, Inc.,
    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 
    See the full license in the file "LICENSE" in the top level distribution directory
    *************************************************************************************/
    /*  END LEGAL */
 
#ifndef GRID_PERF_PROFILING_H
#define GRID_PERF_PROFILING_H
 
#include <sstream>
#include <iostream>
#include <functional>
#include <fcntl.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <sys/types.h>
#include <unistd.h>
#include <signal.h>
 
struct System
{
    static void profile(const std::string& name,std::function<void()> body) {
        std::string filename = name.find(".data") == std::string::npos ? (name + ".data") : name;
 
        // Launch profiler
        pid_t pid;
        std::stringstream s;
        s << getpid();
        pid = fork();
        if (pid == 0) {
            auto fd=open("/dev/null",O_RDWR);
            dup2(fd,1);
            dup2(fd,2);
            exit(execl("/usr/bin/perf","perf","record","-o",filename.c_str(),"-p",s.str().c_str(),nullptr));
        }
 
        // Run body
        body();
 
        // Kill profiler  
        kill(pid,SIGINT);
        waitpid(pid,nullptr,0);
    }
 
    static void profile(std::function<void()> body) {
        profile("perf.data",body);
    }
};
 
#endif // GRID_PERF_PROFILING_H