How to measure VRAM consumption on Android?
I want to acquire Android Device VRAM size.
Is there a method for acquisition from the program?
Answer
Let's do some calculation using Nexus One:
Screen resolution is 480x800. So minimum required video memory size would be:
400 * 800 * 4 bytes = 1536000 bytes
Assuming that driver may (and normally should) use several buffers, we should also expect values like:
1536000 * 2 bytes = 3072000 bytes
1536000 * 3 bytes = 4608000 bytes
etc...
It would be weird to have values that are not multiple of 1536000 (or W x H x 4 in general).
After some searches on Android internals I've found this documentation :
...Android makes two requirements of the driver: a linear address space of mappable memory that it can write to directly...accessing the driver by calling open on /dev/fb0...
So I tried and take size of /dev/graphics/fb0 file (on my device there is no /dev/fb0).
But a direct approach doesn't work:
File file = new File("/dev/graphics/fb0");
file.length(); // ==0, doesn't work, no read access
Using next trick you can get actual size of fb0:
>adb pull /dev/graphics/fb0
1659 KB/s (4608000 bytes in 2.712s)
Video memory is ~4mb (Nexus One). Let's check if this is multiple of Nexus screen size:
4608000/1536000 = 3
It looks like a right value. And we also can say that driver uses three screen buffers.
So, as a conclusion, you can detect video memory size using adb, but you can't use this approach from your android application in runtime due to file access restrictions.