RDMA Changes For Linux 5.12 Add DMA-BUF Support For Peer-To-Peer Transfers With GPUs

[coder]

Sounds exciting. This, pci4/5 (..6) smart access memory, oneAPI and the like may really start a new compute model where the CPU is only one of many compute nodes in a system.

The CPU is still what boots, runs the OS & drivers, manages the memory space, manages security, and basically coordinates things at a high-level. It's still the boss, even if it's not an intermediary of every individual transaction. These devices don't know about UIDs, perms, or userspace processes, but the CPU is what's responsible for extending those constructs so that device-to-device transactions remain private and secure.

If you want to view the inside of a computer more as a network, where there are multiple equal peers, then I think blade servers are probably more along those lines. I believe at least some of them use Ethernet as a backplane.

[mppix]

The CPU is still what boots, runs the OS & drivers, manages the memory space, manages security, and basically coordinates things at a high-level. It's still the boss, even if it's not an intermediary of every individual transaction. These devices don't know about UIDs, perms, or userspace processes, but the CPU is what's responsible for extending those constructs so that device-to-device transactions remain private and secure.

If you want to view the inside of a computer more as a network, where there are multiple equal peers, then I think blade servers are probably more along those lines. I believe at least some of them use Ethernet as a backplane.

Yes, of course. The CPU remains the main hardware that runs the system. However, they become more like a referee from a computation perspective and don't risk to be the bottleneck.

Blade servers and supercomputers can use both Ethernet or more commonly infiniband with direct memory access. In most cases, you still have a central access/management node(s). It certainly also a distributed computation environment at a higher level that would seem complementary.