我曾经有一个任务，从一个运行中的应用程序内部确定以下性能参数:
可用虚拟内存总数 当前使用的虚拟内存 进程当前使用的虚拟内存 可用总RAM 目前使用的RAM 内存目前被我的进程使用 当前CPU使用百分比 %进程当前使用的CPU
这些代码必须在Windows和Linux上运行。尽管这似乎是一个标准的任务，但在手册(WIN32 API, GNU文档)和互联网上找到必要的信息花了我好几天，因为在那里有太多关于这个主题的不完整/不正确/过时的信息。
为了避免别人经历同样的麻烦，我想把所有分散的信息加上我在这里反复试验发现的信息收集在一个地方会是一个好主意。
当前回答
QNX
因为这就像一个“代码维基”，我想从QNX知识库中添加一些代码(注意:这不是我的工作，但我检查了它，它在我的系统上工作得很好):
如何在%:http://www.qnx.com/support/knowledgebase.html?id=50130000000P9b5中获取CPU使用情况
#include <atomic.h>
#include <libc.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/iofunc.h>
#include <sys/neutrino.h>
#include <sys/resmgr.h>
#include <sys/syspage.h>
#include <unistd.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/debug.h>
#include <sys/procfs.h>
#include <sys/syspage.h>
#include <sys/neutrino.h>
#include <sys/time.h>
#include <time.h>
#include <fcntl.h>
#include <devctl.h>
#include <errno.h>
#define MAX_CPUS 32
static float Loads[MAX_CPUS];
static _uint64 LastSutime[MAX_CPUS];
static _uint64 LastNsec[MAX_CPUS];
static int ProcFd = -1;
static int NumCpus = 0;
int find_ncpus(void) {
return NumCpus;
}
int get_cpu(int cpu) {
int ret;
ret = (int)Loads[ cpu % MAX_CPUS ];
ret = max(0,ret);
ret = min(100,ret);
return( ret );
}
static _uint64 nanoseconds( void ) {
_uint64 sec, usec;
struct timeval tval;
gettimeofday( &tval, NULL );
sec = tval.tv_sec;
usec = tval.tv_usec;
return( ( ( sec * 1000000 ) + usec ) * 1000 );
}
int sample_cpus( void ) {
int i;
debug_thread_t debug_data;
_uint64 current_nsec, sutime_delta, time_delta;
memset( &debug_data, 0, sizeof( debug_data ) );
for( i=0; i<NumCpus; i++ ) {
/* Get the sutime of the idle thread #i+1 */
debug_data.tid = i + 1;
devctl( ProcFd, DCMD_PROC_TIDSTATUS,
&debug_data, sizeof( debug_data ), NULL );
/* Get the current time */
current_nsec = nanoseconds();
/* Get the deltas between now and the last samples */
sutime_delta = debug_data.sutime - LastSutime[i];
time_delta = current_nsec - LastNsec[i];
/* Figure out the load */
Loads[i] = 100.0 - ( (float)( sutime_delta * 100 ) / (float)time_delta );
/* Flat out strange rounding issues. */
if( Loads[i] < 0 ) {
Loads[i] = 0;
}
/* Keep these for reference in the next cycle */
LastNsec[i] = current_nsec;
LastSutime[i] = debug_data.sutime;
}
return EOK;
}
int init_cpu( void ) {
int i;
debug_thread_t debug_data;
memset( &debug_data, 0, sizeof( debug_data ) );
/* Open a connection to proc to talk over.*/
ProcFd = open( "/proc/1/as", O_RDONLY );
if( ProcFd == -1 ) {
fprintf( stderr, "pload: Unable to access procnto: %s\n",strerror( errno ) );
fflush( stderr );
return -1;
}
i = fcntl(ProcFd,F_GETFD);
if(i != -1){
i |= FD_CLOEXEC;
if(fcntl(ProcFd,F_SETFD,i) != -1){
/* Grab this value */
NumCpus = _syspage_ptr->num_cpu;
/* Get a starting point for the comparisons */
for( i=0; i<NumCpus; i++ ) {
/*
* the sutime of idle thread is how much
* time that thread has been using, we can compare this
* against how much time has passed to get an idea of the
* load on the system.
*/
debug_data.tid = i + 1;
devctl( ProcFd, DCMD_PROC_TIDSTATUS, &debug_data, sizeof( debug_data ), NULL );
LastSutime[i] = debug_data.sutime;
LastNsec[i] = nanoseconds();
}
return(EOK);
}
}
close(ProcFd);
return(-1);
}
void close_cpu(void){
if(ProcFd != -1){
close(ProcFd);
ProcFd = -1;
}
}
int main(int argc, char* argv[]){
int i,j;
init_cpu();
printf("System has: %d CPUs\n", NumCpus);
for(i=0; i<20; i++) {
sample_cpus();
for(j=0; j<NumCpus;j++)
printf("CPU #%d: %f\n", j, Loads[j]);
sleep(1);
}
close_cpu();
}
如何获得免费(!)内存:http://www.qnx.com/support/knowledgebase.html?id=50130000000mlbx
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <err.h>
#include <sys/stat.h>
#include <sys/types.h>
int main( int argc, char *argv[] ){
struct stat statbuf;
paddr_t freemem;
stat( "/proc", &statbuf );
freemem = (paddr_t)statbuf.st_size;
printf( "Free memory: %d bytes\n", freemem );
printf( "Free memory: %d KB\n", freemem / 1024 );
printf( "Free memory: %d MB\n", freemem / ( 1024 * 1024 ) );
return 0;
}
其他回答
Linux
读取内存和加载数的一种可移植方法是sysinfo调用
使用
#include <sys/sysinfo.h>
int sysinfo(struct sysinfo *info);
描述
Until Linux 2.3.16, sysinfo() used to return information in the
following structure:
struct sysinfo {
long uptime; /* Seconds since boot */
unsigned long loads[3]; /* 1, 5, and 15 minute load averages */
unsigned long totalram; /* Total usable main memory size */
unsigned long freeram; /* Available memory size */
unsigned long sharedram; /* Amount of shared memory */
unsigned long bufferram; /* Memory used by buffers */
unsigned long totalswap; /* Total swap space size */
unsigned long freeswap; /* swap space still available */
unsigned short procs; /* Number of current processes */
char _f[22]; /* Pads structure to 64 bytes */
};
and the sizes were given in bytes.
Since Linux 2.3.23 (i386), 2.3.48 (all architectures) the structure
is:
struct sysinfo {
long uptime; /* Seconds since boot */
unsigned long loads[3]; /* 1, 5, and 15 minute load averages */
unsigned long totalram; /* Total usable main memory size */
unsigned long freeram; /* Available memory size */
unsigned long sharedram; /* Amount of shared memory */
unsigned long bufferram; /* Memory used by buffers */
unsigned long totalswap; /* Total swap space size */
unsigned long freeswap; /* swap space still available */
unsigned short procs; /* Number of current processes */
unsigned long totalhigh; /* Total high memory size */
unsigned long freehigh; /* Available high memory size */
unsigned int mem_unit; /* Memory unit size in bytes */
char _f[20-2*sizeof(long)-sizeof(int)]; /* Padding to 64 bytes */
};
and the sizes are given as multiples of mem_unit bytes.
QNX
因为这就像一个“代码维基”，我想从QNX知识库中添加一些代码(注意:这不是我的工作，但我检查了它，它在我的系统上工作得很好):
如何在%:http://www.qnx.com/support/knowledgebase.html?id=50130000000P9b5中获取CPU使用情况
#include <atomic.h>
#include <libc.h>
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/iofunc.h>
#include <sys/neutrino.h>
#include <sys/resmgr.h>
#include <sys/syspage.h>
#include <unistd.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/debug.h>
#include <sys/procfs.h>
#include <sys/syspage.h>
#include <sys/neutrino.h>
#include <sys/time.h>
#include <time.h>
#include <fcntl.h>
#include <devctl.h>
#include <errno.h>
#define MAX_CPUS 32
static float Loads[MAX_CPUS];
static _uint64 LastSutime[MAX_CPUS];
static _uint64 LastNsec[MAX_CPUS];
static int ProcFd = -1;
static int NumCpus = 0;
int find_ncpus(void) {
return NumCpus;
}
int get_cpu(int cpu) {
int ret;
ret = (int)Loads[ cpu % MAX_CPUS ];
ret = max(0,ret);
ret = min(100,ret);
return( ret );
}
static _uint64 nanoseconds( void ) {
_uint64 sec, usec;
struct timeval tval;
gettimeofday( &tval, NULL );
sec = tval.tv_sec;
usec = tval.tv_usec;
return( ( ( sec * 1000000 ) + usec ) * 1000 );
}
int sample_cpus( void ) {
int i;
debug_thread_t debug_data;
_uint64 current_nsec, sutime_delta, time_delta;
memset( &debug_data, 0, sizeof( debug_data ) );
for( i=0; i<NumCpus; i++ ) {
/* Get the sutime of the idle thread #i+1 */
debug_data.tid = i + 1;
devctl( ProcFd, DCMD_PROC_TIDSTATUS,
&debug_data, sizeof( debug_data ), NULL );
/* Get the current time */
current_nsec = nanoseconds();
/* Get the deltas between now and the last samples */
sutime_delta = debug_data.sutime - LastSutime[i];
time_delta = current_nsec - LastNsec[i];
/* Figure out the load */
Loads[i] = 100.0 - ( (float)( sutime_delta * 100 ) / (float)time_delta );
/* Flat out strange rounding issues. */
if( Loads[i] < 0 ) {
Loads[i] = 0;
}
/* Keep these for reference in the next cycle */
LastNsec[i] = current_nsec;
LastSutime[i] = debug_data.sutime;
}
return EOK;
}
int init_cpu( void ) {
int i;
debug_thread_t debug_data;
memset( &debug_data, 0, sizeof( debug_data ) );
/* Open a connection to proc to talk over.*/
ProcFd = open( "/proc/1/as", O_RDONLY );
if( ProcFd == -1 ) {
fprintf( stderr, "pload: Unable to access procnto: %s\n",strerror( errno ) );
fflush( stderr );
return -1;
}
i = fcntl(ProcFd,F_GETFD);
if(i != -1){
i |= FD_CLOEXEC;
if(fcntl(ProcFd,F_SETFD,i) != -1){
/* Grab this value */
NumCpus = _syspage_ptr->num_cpu;
/* Get a starting point for the comparisons */
for( i=0; i<NumCpus; i++ ) {
/*
* the sutime of idle thread is how much
* time that thread has been using, we can compare this
* against how much time has passed to get an idea of the
* load on the system.
*/
debug_data.tid = i + 1;
devctl( ProcFd, DCMD_PROC_TIDSTATUS, &debug_data, sizeof( debug_data ), NULL );
LastSutime[i] = debug_data.sutime;
LastNsec[i] = nanoseconds();
}
return(EOK);
}
}
close(ProcFd);
return(-1);
}
void close_cpu(void){
if(ProcFd != -1){
close(ProcFd);
ProcFd = -1;
}
}
int main(int argc, char* argv[]){
int i,j;
init_cpu();
printf("System has: %d CPUs\n", NumCpus);
for(i=0; i<20; i++) {
sample_cpus();
for(j=0; j<NumCpus;j++)
printf("CPU #%d: %f\n", j, Loads[j]);
sleep(1);
}
close_cpu();
}
如何获得免费(!)内存:http://www.qnx.com/support/knowledgebase.html?id=50130000000mlbx
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <err.h>
#include <sys/stat.h>
#include <sys/types.h>
int main( int argc, char *argv[] ){
struct stat statbuf;
paddr_t freemem;
stat( "/proc", &statbuf );
freemem = (paddr_t)statbuf.st_size;
printf( "Free memory: %d bytes\n", freemem );
printf( "Free memory: %d KB\n", freemem / 1024 );
printf( "Free memory: %d MB\n", freemem / ( 1024 * 1024 ) );
return 0;
}
在Linux上，你不能/不应该通过SysInfo的freeram或在totalram上做一些算术来获得“总的可用物理内存”。
推荐的方法是读取proc/meminfo，引用kernel/git/torvalds/linux。Git， /proc/meminfo提供估计可用内存:
许多负载平衡和工作负载放置程序检查/proc/meminfo到 估计有多少可用的空闲内存。他们通常这样做 把"免费"和"缓存"加起来，十年前还好，但现在 今天肯定是错的。
在/proc/meminfo中提供这样的估计更方便。如果将来事情发生改变，我们只需要在一个地方改变它。
一种方法是亚当·罗森菲尔德(Adam Rosenfield)对“如何确定c++中Linux系统RAM的数量?”建议:读取文件，并使用fscanf抓取行(但不是去MemTotal，去MemAvailable)
同样，如果你想要得到使用的物理内存总量，这取决于你对“使用”的定义，你可能不想从totalram中减去freeram，而是从memtotal中减去memavailable来得到top或htop告诉你的东西。
在Windows中，你可以通过下面的代码获取CPU使用情况:
#include <windows.h>
#include <stdio.h>
//------------------------------------------------------------------------------------------------------------------
// Prototype(s)...
//------------------------------------------------------------------------------------------------------------------
CHAR cpuusage(void);
//-----------------------------------------------------
typedef BOOL ( __stdcall * pfnGetSystemTimes)( LPFILETIME lpIdleTime, LPFILETIME lpKernelTime, LPFILETIME lpUserTime );
static pfnGetSystemTimes s_pfnGetSystemTimes = NULL;
static HMODULE s_hKernel = NULL;
//-----------------------------------------------------
void GetSystemTimesAddress()
{
if(s_hKernel == NULL)
{
s_hKernel = LoadLibrary(L"Kernel32.dll");
if(s_hKernel != NULL)
{
s_pfnGetSystemTimes = (pfnGetSystemTimes)GetProcAddress(s_hKernel, "GetSystemTimes");
if(s_pfnGetSystemTimes == NULL)
{
FreeLibrary(s_hKernel);
s_hKernel = NULL;
}
}
}
}
//----------------------------------------------------------------------------------------------------------------
//----------------------------------------------------------------------------------------------------------------
// cpuusage(void)
// ==============
// Return a CHAR value in the range 0 - 100 representing actual CPU usage in percent.
//----------------------------------------------------------------------------------------------------------------
CHAR cpuusage()
{
FILETIME ft_sys_idle;
FILETIME ft_sys_kernel;
FILETIME ft_sys_user;
ULARGE_INTEGER ul_sys_idle;
ULARGE_INTEGER ul_sys_kernel;
ULARGE_INTEGER ul_sys_user;
static ULARGE_INTEGER ul_sys_idle_old;
static ULARGE_INTEGER ul_sys_kernel_old;
static ULARGE_INTEGER ul_sys_user_old;
CHAR usage = 0;
// We cannot directly use GetSystemTimes in the C language
/* Add this line :: pfnGetSystemTimes */
s_pfnGetSystemTimes(&ft_sys_idle, /* System idle time */
&ft_sys_kernel, /* system kernel time */
&ft_sys_user); /* System user time */
CopyMemory(&ul_sys_idle , &ft_sys_idle , sizeof(FILETIME)); // Could been optimized away...
CopyMemory(&ul_sys_kernel, &ft_sys_kernel, sizeof(FILETIME)); // Could been optimized away...
CopyMemory(&ul_sys_user , &ft_sys_user , sizeof(FILETIME)); // Could been optimized away...
usage =
(
(
(
(
(ul_sys_kernel.QuadPart - ul_sys_kernel_old.QuadPart)+
(ul_sys_user.QuadPart - ul_sys_user_old.QuadPart)
)
-
(ul_sys_idle.QuadPart-ul_sys_idle_old.QuadPart)
)
*
(100)
)
/
(
(ul_sys_kernel.QuadPart - ul_sys_kernel_old.QuadPart)+
(ul_sys_user.QuadPart - ul_sys_user_old.QuadPart)
)
);
ul_sys_idle_old.QuadPart = ul_sys_idle.QuadPart;
ul_sys_user_old.QuadPart = ul_sys_user.QuadPart;
ul_sys_kernel_old.QuadPart = ul_sys_kernel.QuadPart;
return usage;
}
//------------------------------------------------------------------------------------------------------------------
// Entry point
//------------------------------------------------------------------------------------------------------------------
int main(void)
{
int n;
GetSystemTimesAddress();
for(n=0; n<20; n++)
{
printf("CPU Usage: %3d%%\r", cpuusage());
Sleep(2000);
}
printf("\n");
return 0;
}
Mac OS X
总虚拟内存
这在Mac OS X上很棘手，因为它不像Linux那样使用预设的交换分区或文件。以下是苹果公司文档中的一段:
注意:与大多数基于unix的操作系统不同，Mac OS X不为虚拟内存使用预先分配的交换分区。相反，它会使用机器引导分区上的所有可用空间。
因此，如果想知道还有多少虚拟内存可用，就需要知道根分区的大小。你可以这样做:
struct statfs stats;
if (0 == statfs("/", &stats))
{
myFreeSwap = (uint64_t)stats.f_bsize * stats.f_bfree;
}
当前使用的虚拟总数
使用“vm. conf”调用systcl。Swapusage "键提供有关交换使用的有趣信息:
sysctl -n vm.swapusage
vm.swapusage: total = 3072.00M used = 2511.78M free = 560.22M (encrypted)
如果如上一节所述需要更多的交换空间，这里显示的总交换空间使用情况不会发生变化。总的就是当前掉期的总和。在c++中，可以这样查询这些数据:
xsw_usage vmusage = {0};
size_t size = sizeof(vmusage);
if( sysctlbyname("vm.swapusage", &vmusage, &size, NULL, 0)!=0 )
{
perror( "unable to get swap usage by calling sysctlbyname(\"vm.swapusage\",...)" );
}
请注意，在sysctl.h中声明的“xsw_usage”似乎没有文档，我怀疑有一种更可移植的方式来访问这些值。
进程当前使用的虚拟内存
可以使用task_info函数获取当前进程的统计信息。这包括进程的当前驻留大小和当前虚拟大小。
#include<mach/mach.h>
struct task_basic_info t_info;
mach_msg_type_number_t t_info_count = TASK_BASIC_INFO_COUNT;
if (KERN_SUCCESS != task_info(mach_task_self(),
TASK_BASIC_INFO, (task_info_t)&t_info,
&t_info_count))
{
return -1;
}
// resident size is in t_info.resident_size;
// virtual size is in t_info.virtual_size;
可用总RAM
使用sysctl系统函数，系统中可用的物理RAM数量如下所示:
#include <sys/types.h>
#include <sys/sysctl.h>
...
int mib[2];
int64_t physical_memory;
mib[0] = CTL_HW;
mib[1] = HW_MEMSIZE;
length = sizeof(int64_t);
sysctl(mib, 2, &physical_memory, &length, NULL, 0);
当前使用的RAM
可以从host_statistics系统函数获得一般内存统计信息。
#include <mach/vm_statistics.h>
#include <mach/mach_types.h>
#include <mach/mach_init.h>
#include <mach/mach_host.h>
int main(int argc, const char * argv[]) {
vm_size_t page_size;
mach_port_t mach_port;
mach_msg_type_number_t count;
vm_statistics64_data_t vm_stats;
mach_port = mach_host_self();
count = sizeof(vm_stats) / sizeof(natural_t);
if (KERN_SUCCESS == host_page_size(mach_port, &page_size) &&
KERN_SUCCESS == host_statistics64(mach_port, HOST_VM_INFO,
(host_info64_t)&vm_stats, &count))
{
long long free_memory = (int64_t)vm_stats.free_count * (int64_t)page_size;
long long used_memory = ((int64_t)vm_stats.active_count +
(int64_t)vm_stats.inactive_count +
(int64_t)vm_stats.wire_count) * (int64_t)page_size;
printf("free memory: %lld\nused memory: %lld\n", free_memory, used_memory);
}
return 0;
}
这里需要注意的是，在Mac OS x中有五种类型的内存页，它们如下所示:
Wired pages that are locked in place and cannot be swapped out Active pages that are loading into physical memory and would be relatively difficult to swap out Inactive pages that are loaded into memory, but haven't been used recently and may not even be needed at all. These are potential candidates for swapping. This memory would probably need to be flushed. Cached pages that have been some how cached that are likely to be easily reused. Cached memory probably would not require flushing. It is still possible for cached pages to be reactivated Free pages that are completely free and ready to be used.
值得注意的是，仅仅因为Mac OS X可能会显示很少的实际空闲内存，这可能不是一个很好的指示有多少准备在短时间内使用。
内存当前被我的进程使用
请参阅上面的“进程当前使用的虚拟内存”。同样的代码也适用。
