c++ - 我怎样才能知道我的 C++ 应用程序在 Mac 上使用了多少内存

Question

我的应用程序中的某些操作使用的内存比我认为的要多，我想记录当前的内存使用情况以帮助识别它们。

是否有系统调用返回当前使用的内存量？

Answer 1

下面的C函数返回进程pid的CPU时间和常驻内存。获取其他进程的资源，需要root权限。您也可以尝试 getrusage()，但我从来没有让它在内存使用方面正常工作。使用 getrusage() 获取 CPU 时间对我来说总是有效。

该函数改编自 ps 和 top 命令的源代码。它是我程序的一部分，用于监视其他进程的内存。

#ifdef __APPLE__

#include <sys/types.h>
#include <sys/sysctl.h>
#include <sys/vmmeter.h>
#include <mach/mach_init.h>
#include <mach/mach_host.h>
#include <mach/mach_port.h>
#include <mach/mach_traps.h>
#include <mach/task_info.h>
#include <mach/thread_info.h>
#include <mach/thread_act.h>
#include <mach/vm_region.h>
#include <mach/vm_map.h>
#include <mach/task.h>
#include <mach/shared_memory_server.h>

typedef struct vmtotal vmtotal_t;

typedef struct { /* dynamic process information */
    size_t rss, vsize;
    double utime, stime;
} RunProcDyn;

/* On Mac OS X, the only way to get enough information is to become root. Pretty frustrating!*/
int run_get_dynamic_proc_info(pid_t pid, RunProcDyn *rpd)
{
    task_t task;
    kern_return_t error;
    mach_msg_type_number_t count;
    thread_array_t thread_table;
    thread_basic_info_t thi;
    thread_basic_info_data_t thi_data;
    unsigned table_size;
    struct task_basic_info ti;

    error = task_for_pid(mach_task_self(), pid, &task);
    if (error != KERN_SUCCESS) {
        /* fprintf(stderr, "++ Probably you have to set suid or become root.\n"); */
        rpd->rss = rpd->vsize = 0;
        rpd->utime = rpd->stime = 0;
        return 0;
    }
    count = TASK_BASIC_INFO_COUNT;
    error = task_info(task, TASK_BASIC_INFO, (task_info_t)&ti, &count);
    assert(error == KERN_SUCCESS);
    { /* adapted from ps/tasks.c */
        vm_region_basic_info_data_64_t b_info;
        vm_address_t address = GLOBAL_SHARED_TEXT_SEGMENT;
        vm_size_t size;
        mach_port_t object_name;
        count = VM_REGION_BASIC_INFO_COUNT_64;
        error = vm_region_64(task, &address, &size, VM_REGION_BASIC_INFO,
                             (vm_region_info_t)&b_info, &count, &object_name);
        if (error == KERN_SUCCESS) {
            if (b_info.reserved && size == (SHARED_TEXT_REGION_SIZE) &&
                ti.virtual_size > (SHARED_TEXT_REGION_SIZE + SHARED_DATA_REGION_SIZE))
            {
                ti.virtual_size -= (SHARED_TEXT_REGION_SIZE + SHARED_DATA_REGION_SIZE);
            }
        }
        rpd->rss = ti.resident_size;
        rpd->vsize = ti.virtual_size;
    }
    { /* calculate CPU times, adapted from top/libtop.c */
        unsigned i;
        rpd->utime = ti.user_time.seconds + ti.user_time.microseconds * 1e-6;
        rpd->stime = ti.system_time.seconds + ti.system_time.microseconds * 1e-6;
        error = task_threads(task, &thread_table, &table_size);
        assert(error == KERN_SUCCESS);
        thi = &thi_data;
        for (i = 0; i != table_size; ++i) {
            count = THREAD_BASIC_INFO_COUNT;
            error = thread_info(thread_table[i], THREAD_BASIC_INFO, (thread_info_t)thi, &count);
            assert(error == KERN_SUCCESS);
            if ((thi->flags & TH_FLAGS_IDLE) == 0) {
                rpd->utime += thi->user_time.seconds + thi->user_time.microseconds * 1e-6;
                rpd->stime += thi->system_time.seconds + thi->system_time.microseconds * 1e-6;
            }
            if (task != mach_task_self()) {
                error = mach_port_deallocate(mach_task_self(), thread_table[i]);
                assert(error == KERN_SUCCESS);
            }
        }
        error = vm_deallocate(mach_task_self(), (vm_offset_t)thread_table, table_size * sizeof(thread_array_t));
        assert(error == KERN_SUCCESS);
    }
    mach_port_deallocate(mach_task_self(), task);
    return 0;
}

#endif /* __APPLE__ */