On 05/06/2014 12:34 PM, Linus Torvalds wrote: > On Tue, May 6, 2014 at 9:30 AM, Rik van Riel <riel@xxxxxxxxxx> wrote: >> >> The GPU runs a lot faster when using video memory, instead >> of system memory, on the other side of the PCIe bus. > > The nineties called, and they want their old broken model back. > > Get with the times. No high-performance future GPU will ever run > behind the PCIe bus. We still have a few straggling historical > artifacts, but everybody knows where the future is headed. > > They are already cache-coherent because flushing caches etc was too > damn expensive. They're getting more so. I suppose that VRAM could simply be turned into a very high capacity CPU cache for the GPU, for the case where people want/need an add-on card. With a few hundred MB of "CPU cache" on the video card, we could offload processing to the GPU very easily, without having to worry about multiple address or page table formats on the CPU side. A new generation of GPU hardware seems to come out every six months or so, so I guess we could live with TLB invalidations to the first generations of hardware being comically slow :) -- All rights reversed -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>