Free VRam on OS X
does anyone know how to get the free(!) vram on os x?
I know that you can query for a registry entry:
typeCode = IORegistryEntrySearchCFProperty(dspPort,kIOServicePlane,CFSTR(kIOFBMemorySizeKey),
kCFAllocatorDefault,
kIORegistryIterateRecursively | kIORegistryIterateParents);
but this will return ALL vram, not the free vram. Under windows you can query for free VRAM using directshow
mDDrawResult = DirectDrawCreate(NULL, &开发者_运维知识库;mDDraw, NULL);
mDDrawResult = mDDraw->QueryInterface(IID_IDirectDraw2, (LPVOID *)&mDDraw2);
DDSCAPS ddscaps;
DWORD totalmem, freemem;
ddscaps.dwCaps = DDSCAPS_OFFSCREENPLAIN | DDSCAPS_VIDEOMEMORY;
mDDrawResult = mDDraw2->GetAvailableVidMem(&ddscaps, &totalmem, &freemem);
Ugly, but it works. Anyone knows the osx way?
Best Wendy
answering myself so others may use this:
#include <IOKit/graphics/IOGraphicsLib.h>
size_t currentFreeVRAM()
{
kern_return_t krc;
mach_port_t masterPort;
krc = IOMasterPort(bootstrap_port, &masterPort);
if (krc == KERN_SUCCESS)
{
CFMutableDictionaryRef pattern = IOServiceMatching(kIOAcceleratorClassName);
//CFShow(pattern);
io_iterator_t deviceIterator;
krc = IOServiceGetMatchingServices(masterPort, pattern, &deviceIterator);
if (krc == KERN_SUCCESS)
{
io_object_t object;
while ((object = IOIteratorNext(deviceIterator)))
{
CFMutableDictionaryRef properties = NULL;
krc = IORegistryEntryCreateCFProperties(object, &properties, kCFAllocatorDefault, (IOOptionBits)0);
if (krc == KERN_SUCCESS)
{
CFMutableDictionaryRef perf_properties = (CFMutableDictionaryRef) CFDictionaryGetValue( properties, CFSTR("PerformanceStatistics") );
//CFShow(perf_properties);
// look for a number of keys (this is mostly reverse engineering and best-guess effort)
const void* free_vram_number = CFDictionaryGetValue(perf_properties, CFSTR("vramFreeBytes"));
if (free_vram_number)
{
ssize_t vramFreeBytes;
CFNumberGetValue( (CFNumberRef) free_vram_number, kCFNumberSInt64Type, &vramFreeBytes);
return vramFreeBytes;
}
}
if (properties) CFRelease(properties);
IOObjectRelease(object);
}
IOObjectRelease(deviceIterator);
}
}
return 0; // when we come here, this is a fail
}
- i am somewhat surprised that this query takes almost 3 msec ..
- be aware that there may be more than one accelerator on your system ( eg. macbook ) so be sure you select the proper one for the query
精彩评论