/*************************************************************************************

    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