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Kernel. Org" Subject: Re: New subsystem for acceleration devices Message-Id: <20220804182740.734658fd7b89c3bc50cd4c03@samsung.com> In-Reply-To: X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.30; i686-pc-mingw32) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFuphk+LIzCtJLcpLzFFi42LZdlhTV5d34uskgwe/uSxOXF/EZPF30jF2 iyut01ktmhevZ7O4vGsOm8WFF7dZLa48D3Bg9/j9axKjx4uv25g9ds66y+6xf+4ado9bq409 Pm+SC2CLyrbJSE1MSS1SSM1Lzk/JzEu3VfIOjneONzUzMNQ1tLQwV1LIS8xNtVVy8QnQdcvM AbpESaEsMacUKBSQWFyspG9nU5RfWpKqkJFfXGKrlFqQklNgWqBXnJhbXJqXrpeXWmJlaGBg ZApUmJCdcWTuf7aCRpmKjWfusTcwvhTtYuTkkBAwkXh4upu5i5GLQ0hgB6NE2/9TLBDOJ0aJ 2R/vQ2U+M0o8P3CXBaZl2vs77BCJXYwSfYsXs0E4HUwSrY0H2UCqWARUJBpWN4PZbAKqEjNn rGEHsUUE1CWu7esBa2AW6GWSeHO5jRkkISxgLHF252+gBDsHr4CjxPMwkCinQKDEjhk72CAW W0jc7VnB2sXIAVQhKPF3hzBImFlAXmL72zlgh0oItHJIvF87gxGi3kVi79zHUL3CEq+Ob2GH sKUkXva3QdnZElM6FkE9ViBx7vlWZpD5EkDXXFyRAmIyC2hKrN+lD1GhKLHz91xGiLV8Eu++ 9rBCVPNKdLQJQZQoSSz5cxhquITE1BnfmCBsD4mt9w+xQgLqALPEzSmrmSYwKsxCeGYWkmdm ISxewMi8ilEstaA4Nz212LDACB69yfm5mxjByVLLbAfjpLcf9A4xMnEwHmKU4GBWEuFdYfk6 SYg3JbGyKrUoP76oNCe1+BCjKTBiJjJLiSbnA9N1Xkm8oYmlgYmZkbGJhaGZoZI476pppxOF BNITS1KzU1MLUotg+pg4OKUamDxT+4OahT4tTJ2jYzg/IszkzNdm9ellJsvjiww0a55tkvkw h+fujP9PNpw3zuvQ2Pl9ov6EBUe29SxeuNju0rY89bBkeYbuXRMarz429DJ2mDh99asFNzZd uP0+dDHHmpMX589MXrt1VeCsjA+aG+28+KfeDH4rHNZ7xnVJYdbCit6/hWYhe6qcFlz5me75 Tb/eMXTzoUuuyZ/Ui9/u0l798cQ1DydzFbZXbSYhTbd5KnvvnHDo/d1V2PF6y3X+59VpD4L8 8zscVwlsmrR5cbNPJ59d2rKOuU2c158JqOqf7yoX/XG8J6+H59WOD/+vKbF3KbCH3uzWusvc MvPZasvtexjUjRZZMho1Bf7d+FuJpTgj0VCLuag4EQAFwinyHwQAAA== X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFrrPLMWRmVeSWpSXmKPExsWy7bCSnC7PxNdJBtuXyVmcuL6IyeLvpGPs Fldap7NaNC9ez2ZxedccNosLL26zWlx5HuDA7vH71yRGjxdftzF77Jx1l91j/9w17B63Vht7 fN4kF8AWxWWTkpqTWZZapG+XwJVxZO5/toJGmYqNZ+6xNzC+FO1i5OSQEDCRmPb+DnsXIxeH kMAORokF554xQiQkJDbdW87cxcgBZAtLHD5cDFHTxiRxe8EWsBoWARWJhtXNbCA2m4CqxMwZ a9hBbBEBdYlr+3rYQBqYBXqZJE4tucwCkhAWMJY4u/M3UIKdg1fAUeJ5GEiUUyBQYseMHWwQ 8w8wS9ycspoJ4gYLibs9K1hBbuAVEJT4u0MYJMwsoCXx8NctFghbXmL72znMExgFZyFUzUJS NQtJ1QJG5lWMkqkFxbnpucWGBUZ5qeV6xYm5xaV56XrJ+bmbGMFxoKW1g3HPqg96hxiZOBgP MUpwMCuJ8K6wfJ0kxJuSWFmVWpQfX1Sak1p8iFGag0VJnPdC18l4IYH0xJLU7NTUgtQimCwT B6dUA5OVslyQd1F43xcT1R0lu7eeWpebMulSrJbDubz8Zm9lrqAM8Wl/k1xyTfuj1eZHZZYY Fk76lW52R72g37UvIuq9LpOl1JkJuiWT65o42M4GnJ1Vk6t3Wcf7w80XtV7PZ3f0sE+evSDg dtfFhxyxrnM6WlrUMx8J6XY0bloS+sl+1svntZ3veM8sYPh502ahSxxDVmiQqoH92xanj7y8 RX+1mnWiWHgqTpYriS2+vKj71lXx3X8K1PwXOp8RE48+Zvfuh4bEca3yY3UbnpTwS/+fnaIy 26/V8Hzg3pkHGt1jTV4f5ozc2/vv7kFfjl3JJet4Y8JlzOYGtt9d2DafreUr445Hvu1NU+vq n/kpsRRnJBpqMRcVJwIAGzgn7fICAAA= X-CMS-MailID: 20220804092740epcas1p4db7cd84005f225973819bac98dd4e32f X-Msg-Generator: CA Content-Type: text/plain; charset="utf-8" X-Sendblock-Type: SVC_REQ_APPROVE CMS-TYPE: 101P DLP-Filter: Pass X-CFilter-Loop: Reflected X-CMS-RootMailID: 20220804064719epcas1p2ba6291b7204495ffb46e2d2c6988fdea References: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 4 Aug 2022 09:46:49 +0300 Oded Gabbay wrote: > On Thu, Aug 4, 2022 at 2:32 AM Daniel Stone wrote: > > > > Hi Oded, > > > > On Wed, 3 Aug 2022 at 21:21, Oded Gabbay wrote: > > > The reason it happened now is because I saw two drivers, which are > > > doing h/w acceleration for AI, trying to be accepted to the misc > > > subsystem. > > > > Why misc? > You will need to ask them ;) > Seriously, I guess they thought they were not gpu drivers and didn't > find anything else to go to. > And at least for one of them, I remember Greg and Arnd pointing them to misc. > Hi, Daniel. Samsung NPU driver is one of the trier to be a misc device. There is some reasons that it chooses misc, but it can be simply said that GPU was not a perfect suit for NPU. AI workload is not limited in graphical job, it can be NLP, data analysis or training job. The GPU/DRM can work for them, but its description is not for them. e.g. AI workloads needs to manage ai model data as well as input data. I guess it can be working with GEM object, and needs to be expaned for model information. But I have a question that DRM accept this specialized GEM, thus it's not related to Graphics. Other subsystem was simliar, so I only could choose misc device. IMHO, at the same reason, I'm positive on Oded's working, expecting that the new subsystem could be more specialized for AI workload. thanks, Jiho > > > > > Regarding the open source userspace rules in drm - yes, I think your > > > rules are too limiting for the relatively young AI scene, and I saw at > > > the 2021 kernel summit that other people from the kernel community > > > think that as well. > > > But that's not the main reason, or even a reason at all for doing > > > this. After all, at least for habana, we open-sourced our compiler and > > > a runtime library. And Greg also asked those two drivers if they have > > > matching open-sourced user-space code. > > > > > > And a final reason is that I thought this can also help in somewhat > > > reducing the workload on Greg. I saw in the last kernel summit there > > > was a concern about bringing more people to be kernel maintainers so I > > > thought this is a step in the right direction. > > > > Can you please explain what the reason is here? > > > > Everything you have described - uniform device enumeration, common job > > description, memory management helpers, unique job submission format, > > etc - applies exactly to DRM. If open userspace is not a requirement, > > and bypassing Greg's manual merging is a requirement, then I don't see > > what the difference is between DRM and this new bespoke subsystem. It > > would be great to have these differences enumerated in email as well > > as in kerneldoc. > I don't think preparing such a list at this point is relevant, because > I don't have a full-featured subsystem ready, which I can take and > list all its features and compare it with drm. > I have a beginning of a subsystem, with very minimal common code, and > I planned for it to grow with time and with the relevant participants. > > And regarding the serspace issue, I believe it will be less stringent > than in drm. > For example, afaik in drm you must upstream your LLVM fork to the > mainline LLVM tree. This is something that is really a heavy-lifting > task for most, if not all, companies. > So this is a requirement I think we can forgo. > > Thanks, > Oded > > > > > Cheers, > > Daniel >