On Friday, 20 February 2015 at 10:05:34 UTC, francesco.cattoglio
wrote:
On Wednesday, 18 February 2015 at 18:14:19 UTC, luminousone
wrote:
HSA does work with discrete gpu's and not just the embedded
stuff, And I believe that HSA can be used to accelerate OpenCL
2.0, via copyless cache coherent memory access.
Unless I'm mistaken, it will more like the opposite: HSA will
use OpenCL 2.0 as a backend to do that kind of "copyless" GPGPU
acceleration.
HSAIL does not depend on opencl, and it supports more then
copyless gpgpu acceleration, as it said, it has been access to
virtual memory, including the program stack.
HSA defines changes to the MMU, IOMMU, cpu cache coherency
protocol, a new bytecode(HSAIL), a software stack built around
llvm and its own backend in the gpu device driver.
OpenCL 2.0, generally obtains its copyless accel from remapping
the gpu memory into system memory, not from direct access to
virtual memory, Intel supports a form of copyless accel via this
remapping system.
The major difference between the two systems, is that HSA can
access any arbitrary location in memory, where as OpenCL must
still rely on the pointers being mapped for use.
HSA has for example have complete access to runtime type
reflection, vtable pointers, you could have a linked list or a
tree that is allocated arbitrarily in memory.
