On Tue, Jul 6, 2021 at 4:17 PM Daniel Vetter <daniel@xxxxxxxx> wrote: > > On Tue, Jul 6, 2021 at 2:46 PM Oded Gabbay <oded.gabbay@xxxxxxxxx> wrote: > > > > On Tue, Jul 6, 2021 at 3:23 PM Daniel Vetter <daniel@xxxxxxxx> wrote: > > > > > > On Tue, Jul 06, 2021 at 02:21:10PM +0200, Christoph Hellwig wrote: > > > > On Tue, Jul 06, 2021 at 10:40:37AM +0200, Daniel Vetter wrote: > > > > > > Greg, I hope this will be good enough for you to merge this code. > > > > > > > > > > So we're officially going to use dri-devel for technical details review > > > > > and then Greg for merging so we don't have to deal with other merge > > > > > criteria dri-devel folks have? > > > > > > > > > > I don't expect anything less by now, but it does make the original claim > > > > > that drivers/misc will not step all over accelerators folks a complete > > > > > farce under the totally-not-a-gpu banner. > > > > > > > > > > This essentially means that for any other accelerator stack that doesn't > > > > > fit the dri-devel merge criteria, even if it's acting like a gpu and uses > > > > > other gpu driver stuff, you can just send it to Greg and it's good to go. > > > > > > > > > > There's quite a lot of these floating around actually (and many do have > > > > > semi-open runtimes, like habanalabs have now too, just not open enough to > > > > > be actually useful). It's going to be absolutely lovely having to explain > > > > > to these companies in background chats why habanalabs gets away with their > > > > > stack and they don't. > > > > > > > > FYI, I fully agree with Daniel here. Habanlabs needs to open up their > > > > runtime if they want to push any additional feature in the kernel. > > > > The current situation is not sustainable. > > Well, that's like, your opinion... > > > > > > > > Before anyone replies: The runtime is open, the compiler is still closed. > > > This has become the new default for accel driver submissions, I think > > > mostly because all the interesting bits for non-3d accelerators are in the > > > accel ISA, and no longer in the runtime. So vendors are fairly happy to > > > throw in the runtime as a freebie. > > > > > > It's still incomplete, and it's still useless if you want to actually hack > > > on the driver stack. > > > -Daniel > > > -- > > I don't understand what's not sustainable here. > > > > There is zero code inside the driver that communicates or interacts > > with our TPC code (TPC is the Tensor Processing Core). > > Even submitting works to the TPC is done via a generic queue > > interface. And that queue IP is common between all our engines > > (TPC/DMA/NIC). The driver provides all the specs of that queue IP, > > because the driver's code is handling that queue. But why is the TPC > > compiler code even relevant here ? > > Can I use the hw how it's intended to be used without it? You can use the h/w with the userspace stack we are providing in our github repos + website. Part of the userspace stack is open sourced, part is closed source. And I'm actively working on opening up more stuff as we go along. > > If the answer is no, then essentially what you're doing with your > upstream driver is getting all the benefits of an upstream driver, > while upstream gets nothing. We can't use your stack, not as-is. Sure > we can use the queue, but we can't actually submit anything > interesting. And I'm pretty sure the point of your hw is to do more > than submit no-op packets to a queue. > > This is all "I want my cake and eat it too" approach to upstreaming, > and it's totally fine attitude to have, but if you don't see why > there's maybe an different side to it then I don't get what you're > arguing. Upstream isn't free lunch for nothing. > > Frankly I'm starting to assume you're arguing this all in bad faith > just because habanalabds doesn't want to actually have an open driver > stack, so any attack is good, no matter what. Which is also what > everyone else does who submits their accel driver to upstream, and > which gets us back to the starting point of this sub-thread of me > really appreciation how this will improve background discussions going > forward for everyone. > > Like if the requirement for accel drivers truly is that you can submit > a dummy command to the queues then I have about 5-10 drivers at least > I could merge instantly. For something like the intel gpu driver it > would be about 50 lines of code (including all the structure boiler > plate the ioctls require)in userspace to submit a dummy queue command. > GPU and accel vendors would really love that, because it would allow > them to freeload on upstream and do essentially nothing in return. > > And we'd end up with an unmaintainable disaster of a gpu or well > accelerator subsystem because there's nothing you can change or > improve because all the really useful bits of the stack are closed. > And ofc that's not any companies problem anymore, so ofc you with the > habanalabs hat on don't care and call this *extreme*. > > > btw, you can today see our TPC code at > > https://github.com/HabanaAI/Habana_Custom_Kernel > > There is a link there to the TPC user guide and link to download the > > LLVM compiler. > > I got stuck clicking links before I found the source for that llvm > compiler. Can you give me a direct link to the repo with sourcecode > instead please? The source code for the LLVM compiler is not available yet. That's one of the parts I'm working on getting in the open. Having said that, I don't think (and I'm not alone at this) that this should be a pre-requirement for upstreaming kernel drivers of any type. And we had this discussion in the past, I'm sure we are both tired of repeating ourselves. > > Thanks, Daniel > -- > Daniel Vetter > Software Engineer, Intel Corporation > http://blog.ffwll.ch
