ParallelAlgorithms/MemoryUsage.cpp at master · DragonSpit/ParallelAlgorithms · GitHub

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// from https://stackoverflow.com/questions/63166/how-to-determine-cpu-and-memory-consumption-from-inside-a-process

#include<stddef.h>
#include<stdio.h>
#include<chrono>
#include<execution>

using std::chrono::duration;
using std::chrono::duration_cast;
using std::chrono::high_resolution_clock;
using std::milli;

#if defined(WIN32) || defined(_WIN32) || defined(__WIN32) && !defined(__CYGWIN__)
#include"windows.h"
#else
#include"sys/types.h"
#include"sys/sysinfo.h"
#endif

unsignedlonglongphysical_memory_used_in_megabytes()
{
#if defined(WIN32) || defined(_WIN32) || defined(__WIN32) && !defined(__CYGWIN__)
MEMORYSTATUSEX memInfo;
	memInfo.dwLength = sizeof(MEMORYSTATUSEX);
GlobalMemoryStatusEx(&memInfo);
//DWORDLONG totalVirtualMem = memInfo.ullTotalPageFile;
//DWORDLONG virtualMemUsed = memInfo.ullTotalPageFile - memInfo.ullAvailPageFile;
//DWORDLONG totalPhysMem = memInfo.ullTotalPhys;
DWORDLONG physMemUsed = memInfo.ullTotalPhys - memInfo.ullAvailPhys;	// physical memory used by the system
//SIZE_T physMemUsedByMe = pmc.WorkingSetSize;	// by current process
return (physMemUsed / (1024ULL * 1024));
#else
structsysinfo memInfo;

sysinfo(&memInfo);
longlong totalVirtualMem = memInfo.totalram;
//Add other values in next statement to avoid int overflow on right hand side...
	totalVirtualMem += memInfo.totalswap;
	totalVirtualMem *= memInfo.mem_unit;
longlong virtualMemUsed = memInfo.totalram - memInfo.freeram;
//Add other values in next statement to avoid int overflow on right hand side...
	virtualMemUsed += memInfo.totalswap - memInfo.freeswap;
	virtualMemUsed *= memInfo.mem_unit;
longlong totalPhysMem = memInfo.totalram;
//Multiply in next statement to avoid int overflow on right hand side...
	totalPhysMem *= memInfo.mem_unit;
longlong physMemUsed = memInfo.totalram - memInfo.freeram;
//Multiply in next statement to avoid int overflow on right hand side...
	physMemUsed *= memInfo.mem_unit;	// total physical memory used by the whole system
return (physMemUsed / (1024ULL * 1024));
#endif
}

unsignedlonglongphysical_memory_total_in_megabytes()
{
#if defined(WIN32) || defined(_WIN32) || defined(__WIN32) && !defined(__CYGWIN__)
MEMORYSTATUSEX memInfo;
	memInfo.dwLength = sizeof(MEMORYSTATUSEX);
GlobalMemoryStatusEx(&memInfo);
//DWORDLONG totalVirtualMem = memInfo.ullTotalPageFile;
//DWORDLONG virtualMemUsed = memInfo.ullTotalPageFile - memInfo.ullAvailPageFile;
DWORDLONG totalPhysMem = memInfo.ullTotalPhys;
//DWORDLONG physMemUsed = memInfo.ullTotalPhys - memInfo.ullAvailPhys;	// physical memory used by the system
//SIZE_T physMemUsedByMe = pmc.WorkingSetSize;	// by current process
return (totalPhysMem / (1024ULL * 1024));
#else
structsysinfo memInfo;

sysinfo(&memInfo);
longlong totalVirtualMem = memInfo.totalram;
//Add other values in next statement to avoid int overflow on right hand side...
	totalVirtualMem += memInfo.totalswap;
	totalVirtualMem *= memInfo.mem_unit;
longlong virtualMemUsed = memInfo.totalram - memInfo.freeram;
//Add other values in next statement to avoid int overflow on right hand side...
	virtualMemUsed += memInfo.totalswap - memInfo.freeswap;
	virtualMemUsed *= memInfo.mem_unit;
longlong totalPhysMem = memInfo.totalram;
//Multiply in next statement to avoid int overflow on right hand side...
	totalPhysMem *= memInfo.mem_unit;
longlong physMemUsed = memInfo.totalram - memInfo.freeram;
//Multiply in next statement to avoid int overflow on right hand side...
	physMemUsed *= memInfo.mem_unit;	// total physical memory used by the whole system
return (totalPhysMem / (1024ULL * 1024));
#endif
}

// Test memory allocation
intTestMemoryAllocation()
{
#if defined(WIN32) || defined(_WIN32) || defined(__WIN32) && !defined(__CYGWIN__)
constsize_tNUM_TIMES = 1000;
constsize_tSIZE_OF_ARRAY = 100'000'000;
unsignedchar* array_of_pointers[NUM_TIMES]{};
size_t sum = 0;

for (size_t i = 0; i < NUM_TIMES; ++i)
	{
 array_of_pointers[i] = newunsignedchar[SIZE_OF_ARRAY];
for (size_t j = 0; j < SIZE_OF_ARRAY; ++j)
 array_of_pointers[i][j] = (unsignedchar)j;
for (size_t j = 0; j < SIZE_OF_ARRAY; ++j)
 sum += array_of_pointers[i][j];
printf("Allocated array: %zu sum = %zu\n", i, sum);
std::this_thread::sleep_for(std::chrono::milliseconds(300));
	}
printf("Final sum = %zu\n", sum);

for (size_t i = 0; i < NUM_TIMES; ++i)
	{
delete[] array_of_pointers[i];
	}
#endif
return0;
}

voidprint_current_memory_space()
{
printf("physical memory used = %llu physical memory total = %llu\n",
physical_memory_used_in_megabytes(), physical_memory_total_in_megabytes());
}

voidtest_lazy_memory_allocation()
{
constsize_tSIZE_OF_ARRAY = 10'000'000'000;
//size_t sum = 0;

print_current_memory_space();

unsignedchar* my_array = newunsignedchar[SIZE_OF_ARRAY];

print_current_memory_space();

for (size_t i = 0; i < (SIZE_OF_ARRAY / 2); ++i)
 my_array[i] = (unsignedchar)i;

print_current_memory_space();

for (size_t i = (SIZE_OF_ARRAY / 2); i < SIZE_OF_ARRAY; ++i)
 my_array[i] = (unsignedchar)i;

print_current_memory_space();

delete[] my_array;

print_current_memory_space();
}