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The OP isn't really about UMA, but about caching. In any case, in Intel's DVMT you have a dedicated memory space for graphics. It is a dynamic amount, but it i
by acchow 3y ago
The OP isn't really about UMA, but about caching.
In any case, in Intel's DVMT you have a dedicated memory space for graphics. It is a dynamic amount, but it is still dedicated for graphics. You need to copy data from system memory over to graphics memory for it to be handled.
In UMA, no data copying is needed. There's 1 memory space
- kcb 3y agoZero copy shared memory absolutely is available on all modern IGPUs. Do people really think such a low hanging fruit was ignored for the past decades? https://www.intel.com/content/dam/develop/external/us/en/documents/opencl-zero-copy-in-opencl-1-2.pdf https://www.intel.com/content/dam/develop/external/us/en/doc... https://en.wikipedia.org/wiki/Heterogeneous_System_Architecture https://en.wikipedia.org/wiki/Heterogeneous_System_Architect...
- kllrnohj 3y ago> Do people really think such a low hanging fruit was ignored for the past decades? Yes, they do, it's mentioned as some major M1 revolutionary technology all the time. It's utterly absurd, but that's the power of Apple's marketing.
- NikkiA 3y agoHell, the UMA was considered a downside on the original XBOX because everyone was used to each processor having it's own memory bus, so even though the bus was (for the time) a sprightly 6.4GB/s, it was considered lesser.
- buildbot 3y agoI can’t run llama on an intel iGPU, because it OOMs - the memory is unified because it’s in the same space and shared on M1. Not just marketing.
- menaerus 3y agoSo, how much memory is available to your Intel iGPU? What was the machine? If it OOMs, then one valid assumption is that it OOMs because it has less memory available than there is for a GPU on M1 but we can't know that if you fail to mention the specs.
- userbinator 3y agoYou need to copy data from system memory over to graphics memory for it to be handled. No you don't. You can map any page of physical RAM into the GPU address space. This has been the case since at least the Intel i810. Here's a relevant part from the i815 documentation: https://i.imgur.com/p53Dxsn.png https://i.imgur.com/p53Dxsn.png