如何使用C++在运行时获取内存？

我需要在我的程序运行时获取mem使用VIRT和RES并显示它们.

到目前为止我尝试了什么:

getrusage(http://linux.die.net/man/2/getrusage)

int who = RUSAGE_SELF; 
struct rusage usage; 
int ret; 

ret=getrusage(who,&usage);

cout<

但我总是0.


1> Don Wakefiel..：
在Linux上,我从未找到过ioctl()解决方案.对于我们的应用程序,我们基于读取/ proc/pid中的文件编写了一个通用实用程序例程.有许多这些文件会产生不同的结果.这是我们解决的问题(问题是标记为C++,我们使用C++构造处理I/O,但如果需要,它应该很容易适应C i/o例程):

#include 
#include 
#include 
#include 
#include 

//////////////////////////////////////////////////////////////////////////////
//
// process_mem_usage(double &, double &) - takes two doubles by reference,
// attempts to read the system-dependent data for a process' virtual memory
// size and resident set size, and return the results in KB.
//
// On failure, returns 0.0, 0.0

void process_mem_usage(double& vm_usage, double& resident_set)
{
   using std::ios_base;
   using std::ifstream;
   using std::string;

   vm_usage     = 0.0;
   resident_set = 0.0;

   // 'file' stat seems to give the most reliable results
   //
   ifstream stat_stream("/proc/self/stat",ios_base::in);

   // dummy vars for leading entries in stat that we don't care about
   //
   string pid, comm, state, ppid, pgrp, session, tty_nr;
   string tpgid, flags, minflt, cminflt, majflt, cmajflt;
   string utime, stime, cutime, cstime, priority, nice;
   string O, itrealvalue, starttime;

   // the two fields we want
   //
   unsigned long vsize;
   long rss;

   stat_stream >> pid >> comm >> state >> ppid >> pgrp >> session >> tty_nr
               >> tpgid >> flags >> minflt >> cminflt >> majflt >> cmajflt
               >> utime >> stime >> cutime >> cstime >> priority >> nice
               >> O >> itrealvalue >> starttime >> vsize >> rss; // don't care about the rest

   stat_stream.close();

   long page_size_kb = sysconf(_SC_PAGE_SIZE) / 1024; // in case x86-64 is configured to use 2MB pages
   vm_usage     = vsize / 1024.0;
   resident_set = rss * page_size_kb;
}

int main()
{
   using std::cout;
   using std::endl;

   double vm, rss;
   process_mem_usage(vm, rss);
   cout << "VM: " << vm << "; RSS: " << rss << endl;
}

        

2> pepper_chico..：
David Robert Nadeau在他的网站上提供了一个很好的自包含多平台C函数来获取进程驻留集大小(物理内存使用):

/*
 * Author:  David Robert Nadeau
 * Site:    http://NadeauSoftware.com/
 * License: Creative Commons Attribution 3.0 Unported License
 *          http://creativecommons.org/licenses/by/3.0/deed.en_US
 */

#if defined(_WIN32)
#include 
#include 

#elif defined(__unix__) || defined(__unix) || defined(unix) || (defined(__APPLE__) && defined(__MACH__))
#include 
#include 

#if defined(__APPLE__) && defined(__MACH__)
#include 

#elif (defined(_AIX) || defined(__TOS__AIX__)) || (defined(__sun__) || defined(__sun) || defined(sun) && (defined(__SVR4) || defined(__svr4__)))
#include 
#include 

#elif defined(__linux__) || defined(__linux) || defined(linux) || defined(__gnu_linux__)
#include 

#endif

#else
#error "Cannot define getPeakRSS( ) or getCurrentRSS( ) for an unknown OS."
#endif





/**
 * Returns the peak (maximum so far) resident set size (physical
 * memory use) measured in bytes, or zero if the value cannot be
 * determined on this OS.
 */
size_t getPeakRSS( )
{
#if defined(_WIN32)
    /* Windows -------------------------------------------------- */
    PROCESS_MEMORY_COUNTERS info;
    GetProcessMemoryInfo( GetCurrentProcess( ), &info, sizeof(info) );
    return (size_t)info.PeakWorkingSetSize;

#elif (defined(_AIX) || defined(__TOS__AIX__)) || (defined(__sun__) || defined(__sun) || defined(sun) && (defined(__SVR4) || defined(__svr4__)))
    /* AIX and Solaris ------------------------------------------ */
    struct psinfo psinfo;
    int fd = -1;
    if ( (fd = open( "/proc/self/psinfo", O_RDONLY )) == -1 )
        return (size_t)0L;      /* Can't open? */
    if ( read( fd, &psinfo, sizeof(psinfo) ) != sizeof(psinfo) )
    {
        close( fd );
        return (size_t)0L;      /* Can't read? */
    }
    close( fd );
    return (size_t)(psinfo.pr_rssize * 1024L);

#elif defined(__unix__) || defined(__unix) || defined(unix) || (defined(__APPLE__) && defined(__MACH__))
    /* BSD, Linux, and OSX -------------------------------------- */
    struct rusage rusage;
    getrusage( RUSAGE_SELF, &rusage );
#if defined(__APPLE__) && defined(__MACH__)
    return (size_t)rusage.ru_maxrss;
#else
    return (size_t)(rusage.ru_maxrss * 1024L);
#endif

#else
    /* Unknown OS ----------------------------------------------- */
    return (size_t)0L;          /* Unsupported. */
#endif
}





/**
 * Returns the current resident set size (physical memory use) measured
 * in bytes, or zero if the value cannot be determined on this OS.
 */
size_t getCurrentRSS( )
{
#if defined(_WIN32)
    /* Windows -------------------------------------------------- */
    PROCESS_MEMORY_COUNTERS info;
    GetProcessMemoryInfo( GetCurrentProcess( ), &info, sizeof(info) );
    return (size_t)info.WorkingSetSize;

#elif defined(__APPLE__) && defined(__MACH__)
    /* OSX ------------------------------------------------------ */
    struct mach_task_basic_info info;
    mach_msg_type_number_t infoCount = MACH_TASK_BASIC_INFO_COUNT;
    if ( task_info( mach_task_self( ), MACH_TASK_BASIC_INFO,
        (task_info_t)&info, &infoCount ) != KERN_SUCCESS )
        return (size_t)0L;      /* Can't access? */
    return (size_t)info.resident_size;

#elif defined(__linux__) || defined(__linux) || defined(linux) || defined(__gnu_linux__)
    /* Linux ---------------------------------------------------- */
    long rss = 0L;
    FILE* fp = NULL;
    if ( (fp = fopen( "/proc/self/statm", "r" )) == NULL )
        return (size_t)0L;      /* Can't open? */
    if ( fscanf( fp, "%*s%ld", &rss ) != 1 )
    {
        fclose( fp );
        return (size_t)0L;      /* Can't read? */
    }
    fclose( fp );
    return (size_t)rss * (size_t)sysconf( _SC_PAGESIZE);

#else
    /* AIX, BSD, Solaris, and Unknown OS ------------------------ */
    return (size_t)0L;          /* Unsupported. */
#endif
}


用法

size_t currentSize = getCurrentRSS( );
size_t peakSize    = getPeakRSS( );


有关更多讨论,请查看网站,它还提供了获取系统物理内存大小的功能.

        
最好将`#pragma comment(lib,"psapi.lib")`添加到`#if defined(_WIN32)`范围. 

3> Paul de Vrie..：
旧:


  
maxrss说明进程的最大可用内存.0表示对该过程没有限制.您可能想要的是非共享数据使用情况ru_idrss.


新:看起来上面实际上并不起作用,因为内核没有填充大部分值.什么工作是从proc获取信息.而不是自己解析它,使用libproc(procps的一部分)更容易,如下所示:

// getrusage.c
#include 
#include 

int main() {
  struct proc_t usage;
  look_up_our_self(&usage);
  printf("usage: %lu\n", usage.vsize);
}


用" gcc -o getrusage getrusage.c -lproc" 编译

        
这是不正确的.maxrss是进程的峰值内存使用量,而不是可用的最大值 - 即getrlimit(RLIMIT_DATA,&rl). 

4> David Courna..：
在linux上,如果你能负担运行时间成本(用于调试),你可以使用valgrind和massif工具:

http://valgrind.org/docs/manual/ms-manual.html

它很重,但非常有用.

        

5> jmanning2k..：
现有答案更适合如何获得正确的价值,但我至少可以解释为什么getrusage不适合你.

man 2 getrusage:


  
上述结构[rusage]取自BSD 4.3 Reno.并非所有字段在Linux下都有意义.现在(Linux 2.4,2.6)只维护字段ru_utime,ru_stime,ru_minflt,ru_majflt和ru_nswap.

        

6> Qsiris..：
Don Wakefield方法的一种更优雅的方法：

#include 
#include 

using namespace std;

int main(){

    int tSize = 0, resident = 0, share = 0;
    ifstream buffer("/proc/self/statm");
    buffer >> tSize >> resident >> share;
    buffer.close();

    long page_size_kb = sysconf(_SC_PAGE_SIZE) / 1024; // in case x86-64 is configured to use 2MB pages
    double rss = resident * page_size_kb;
    cout << "RSS - " << rss << " kB\n";

    double shared_mem = share * page_size_kb;
    cout << "Shared Memory - " << shared_mem << " kB\n";

    cout << "Private Memory - " << rss - shared_mem << "kB\n";
    return 0;
}