> -----Original Message----- > From: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com> > Sent: Sunday, June 6, 2021 09:14 > To: Jerin Jacob <jerinjac...@gmail.com>; Wang, Haiyue <haiyue.w...@intel.com> > Cc: tho...@monjalon.net; Andrew Rybchenko <andrew.rybche...@oktetlabs.ru>; > Yigit, Ferruh > <ferruh.yi...@intel.com>; dpdk-dev <dev@dpdk.org>; Elena Agostini > <eagost...@nvidia.com>; David > Marchand <david.march...@redhat.com>; nd <n...@arm.com>; Honnappa Nagarahalli > <honnappa.nagaraha...@arm.com>; nd <n...@arm.com> > Subject: RE: [dpdk-dev] [PATCH] gpudev: introduce memory API > > <snip> > > > > > > > > > 04/06/2021 17:20, Jerin Jacob: > > > > > On Fri, Jun 4, 2021 at 7:39 PM Thomas Monjalon > > <tho...@monjalon.net> wrote: > > > > > > 04/06/2021 15:59, Andrew Rybchenko: > > > > > > > On 6/4/21 4:18 PM, Thomas Monjalon wrote: > > > > > > > > 04/06/2021 15:05, Andrew Rybchenko: > > > > > > > >> On 6/4/21 3:46 PM, Thomas Monjalon wrote: > > > > > > > >>> 04/06/2021 13:09, Jerin Jacob: > > > > > > > >>>> On Fri, Jun 4, 2021 at 3:58 PM Thomas Monjalon > > <tho...@monjalon.net> wrote: > > > > > > > >>>>> 03/06/2021 11:33, Ferruh Yigit: > > > > > > > >>>>>> On 6/3/2021 8:47 AM, Jerin Jacob wrote: > > > > > > > >>>>>>> On Thu, Jun 3, 2021 at 2:05 AM Thomas Monjalon > > <tho...@monjalon.net> wrote: > > > > > > > >>>>>>>> + [gpudev] (@ref rte_gpudev.h), > > > > > > > >>>>>>> > > > > > > > >>>>>>> Since this device does not have a queue etc? Shouldn't > > > > > > > >>>>>>> make it a library like mempool with vendor-defined ops? > > > > > > > >>>>>> > > > > > > > >>>>>> +1 > > > > > > > >>>>>> > > > > > > > >>>>>> Current RFC announces additional memory allocation > > > > > > > >>>>>> capabilities, which can suits better as extension to > > > > > > > >>>>>> existing memory related library instead of a new device > > abstraction library. > > > > > > > >>>>> > > > > > > > >>>>> It is not replacing mempool. > > > > > > > >>>>> It is more at the same level as EAL memory management: > > > > > > > >>>>> allocate simple buffer, but with the exception it is > > > > > > > >>>>> done on a specific device, so it requires a device ID. > > > > > > > >>>>> > > > > > > > >>>>> The other reason it needs to be a full library is that > > > > > > > >>>>> it will start a workload on the GPU and get completion > > > > > > > >>>>> notification so we can integrate the GPU workload in a > > > > > > > >>>>> packet > > processing pipeline. > > > > > > > >>>> > > > > > > > >>>> I might have confused you. My intention is not to make to fit > > under mempool API. > > > > > > > >>>> > > > > > > > >>>> I agree that we need a separate library for this. My > > > > > > > >>>> objection is only to not call libgpudev and call it > > > > > > > >>>> libgpu. And have APIs with rte_gpu_ instead of > > > > > > > >>>> rte_gpu_dev as it not like existing "device libraries" in > > > > > > > >>>> DPDK and it like other "libraries" in DPDK. > > > > > > > >>> > > > > > > > >>> I think we should define a queue of processing actions, so > > > > > > > >>> it looks like other device libraries. > > > > > > > >>> And anyway I think a library managing a device class, and > > > > > > > >>> having some device drivers deserves the name of device > > > > > > > >>> library. > > > > > > > >>> > > > > > > > >>> I would like to read more opinions. > > > > > > > >> > > > > > > > >> Since the library is an unified interface to GPU device > > > > > > > >> drivers I think it should be named as in the patch - gpudev. > > > > > > > >> > > > > > > > >> Mempool looks like an exception here - initially it was > > > > > > > >> pure SW library, but not there are HW backends and > > > > > > > >> corresponding device drivers. > > > > > > > >> > > > > > > > >> What I don't understand where is GPU specifics here? > > > > > > > > > > > > > > > > That's an interesting question. > > > > > > > > Let's ask first what is a GPU for DPDK? > > > > > > > > I think it is like a sub-CPU with high parallel execution > > > > > > > > capabilities, and it is controlled by the CPU. > > > > > > > > > > > > > > I have no good ideas how to name it in accordance with above > > > > > > > description to avoid "G" which for "Graphics" if understand > > > > > > > correctly. However, may be it is not required. > > > > > > > No strong opinion on the topic, but unbinding from "Graphics" > > > > > > > would be nice. > > > > > > > > > > > > That's a question I ask myself for months now. > > > > > > I am not able to find a better name, and I start thinking that > > > > > > "GPU" is famous enough in high-load computing to convey the idea > > > > > > of what we can expect. > > > > > > > > > > > > > > > The closest I can think of is big-little architecture in ARM SoC. > > > > > https://www.arm.com/why-arm/technologies/big-little > From the application pov, big-little arch is nothing but SMT. Not sure how it > is similar to another > device on PCIe. > > > > > > > > > > > We do have similar architecture, Where the "coprocessor" is part > > > > > of the main CPU. > > > > > It is operations are: > > > > > - Download firmware > > > > > - Memory mapping for Main CPU memory by the co-processor > > > > > - Enq/Deq Jobs from/to Main CPU/Coprocessor CPU. > > > > > > > > Yes it looks like the exact same scope. > > > > I like the word "co-processor" in this context. > > > > > > > > > If your scope is something similar and No Graphics involved here > > > > > then we can remove G. > > > > > > > > Indeed no graphics in DPDK :) > > > > By removing the G, you mean keeping only PU? like "pudev"? > > > > We could also define the G as "General". > > > > > > > > > Coincidentally, Yesterday, I had an interaction with Elena for the > > > > > same for BaseBand related work in ORAN where GPU used as Baseband > > > > > processing instead of Graphics.(So I can understand the big > > > > > picture of this library) > This patch does not provide the big picture view of what the processing looks > like using GPU. It would > be good to explain that. > For ex: > 1) Will the notion of GPU hidden from the application? i.e. is the > application allowed to launch > kernels? > 1a) Will DPDK provide abstract APIs to launch kernels? > This would require us to have the notion of GPU in DPDK and the > application would depend on the > availability of GPU in the system. > 2) Is launching kernels hidden? i.e. the application still calls DPDK > abstract APIs (such as > encryption/decryption APIs) without knowing that the encryption/decryption is > happening on GPU. > This does not require us to have a notion of GPU in DPDK at the API level > > If we keep CXL in mind, I would imagine that in the future the devices on > PCIe could have their own > local memory. May be some of the APIs could use generic names. For ex: > instead of calling it as > "rte_gpu_malloc" may be we could call it as "rte_dev_malloc". This way any > future device which hosts > its own memory that need to be managed by the application, can use these APIs. >
"rte_dev_malloc" sounds a good name, then looks like we need to enhance the 'struct rte_device' with some new ops as: eal: move DMA mapping from bus-specific to generic driver https://patchwork.dpdk.org/project/dpdk/patch/20210331224547.2217759-1-tho...@monjalon.net/ > > > > > > > > > Yes baseband processing is one possible usage of GPU with DPDK. > > > > We could also imagine some security analysis, or any machine learning... > > > > > > > > > I can think of "coprocessor-dev" as one of the name. > > > > > > > > "coprocessor" looks too long as prefix of the functions. > > > > Yes. Libray name can be lengthy, but API prefix should be 3 letters kind > > short > > form will be required. > > > > > > > > > > > > > We do have similar machine learning co-processors(for compute) if > > > > > we can keep a generic name and it is for the above functions we > > > > > may use this subsystem as well in the future. > > > > > > > > > > Accelerator, 'acce_dev' ? ;-) > > > > It may get confused with HW accelerators. > > > > > > Some of the options I can think of. Sorting in my preference. > > > > library name, API prefix > > 1) libhpc-dev, rte_hpc_ (hpc-> Heterogeneous processor compute) > > 2) libhc-dev, rte_hc_ > > (https://en.wikipedia.org/wiki/Heterogeneous_computing see: Example > > hardware) > > 3) libpu-dev, rte_pu_ (pu -> processing unit) > > 4) libhp-dev, rte_hp_ (hp->heterogeneous processor) > > 5) libcoprocessor-dev, rte_cps_ ? > > 6) libcompute-dev, rte_cpt_ ? > > 7) libgpu-dev, rte_gpu_ > These seem to assume that the application can launch its own workload on the > device? Does DPDK need to > provide abstract APIs for launching work on a device? > > > > > > > > > > > > > > > > > Yes that's the idea to share a common synchronization mechanism with > > > > different HW. > > > > > > > > That's cool to have such a big interest in the community for this patch. > > > > > > >
