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MemoryUsed() Function
There is no portable function to measure memory used by a program.
The best measurement is how much memory malloc() has allocated (which GLIB provides).
A second-best measurement is how many resident pages are used.
getrusage(), which is poorly implemented even on FreeBSD and Linux,
is practically useless for measuring memory.
#if OS_APPLE
# include <mach/mach_init.h>
# include <mach/task.h>
#elif OS_UNIX
# include <sstream>
# include <sys/time.h>
# include <time.h>
# if __GLIBC__ // GNU Linux
# include <malloc.h>
# elif OS_FREEBSD
# include <sys/file.h>
# include <sys/sysctl.h>
# include <sys/user.h>
# include <kvm.h>
# endif
#endif
/*****************************************************************************
* Return total amount of bytes allocated.
*****************************************************************************/
unsigned long
MemoryUsed( void )
{
#if __GLIBC__ // GNU Linux
// Per delorie.com:
// Example:
// struct mallinfo info = mallinfo();
// printf("Memory in use: %d bytes\n", info.usmblks + info.uordblks);
// printf("Total heap size: %d bytes\n", info.arena);
struct mallinfo meminfo;
meminfo = mallinfo();
//return meminfo.arena;
return meminfo.usmblks + meminfo.uordblks;
#elif OS_APPLE
// Use Mach functions.
task_basic_info machInfo = { 0 };
mach_port_t machTask = mach_task_self();
mach_msg_type_number_t machCount = TASK_BASIC_INFO_COUNT;
if ( task_info( machTask, TASK_BASIC_INFO, reinterpret_cast<task_info_t>(&machInfo), &machCount ) == KERN_SUCCESS )
return machInfo.resident_size;
else
return 0; // error
#elif OS_FREEBSD
// getrusage() doesn't work right on FreeBSD and anyway it has
// a horrible convoluted interface for measuring memory.
// kvm is reliable but does require linking with the kvm library.
PERSISTENT kvm_t* kd = kvm_open( NULL, "/dev/null", NULL, O_RDONLY, "kvm_open" ); // open once
if ( kd != NULL )
{
// Use FreeBSD kvm function to get the size of resident pages (RSS).
int procCount = 0;
struct kinfo_proc* kp = kvm_getprocs( kd, KERN_PROC_PID, getpid(), &procCount ); // do not free returned struct
if ( (kp != NULL) and (procCount >= 1) ) // in case multiple threads have the same PID
return kp->ki_rssize * getpagesize(); // success
}
return 0; // failed
#else
return 0; // unsupported
#endif
}
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