> > > > On 9/14/22 12:35, Thomas Monjalon wrote: > > > 06/09/2022 14:51, Tom Rix: > > > > On 9/1/22 1:34 PM, Chautru, Nicolas wrote: > > > > > From: Tom Rix <t...@redhat.com> > > > > > > On 8/31/22 6:26 PM, Chautru, Nicolas wrote: > > > > > > > From: Tom Rix <t...@redhat.com> > > > > > > > > On 8/31/22 3:37 PM, Chautru, Nicolas wrote: > > > > > > > > > > > > > Comparing ACC200 & ACC100 header files, I > > > > > > > > > > > > > understand ACC200 is an evolution of the ACC10x > > > > > > > > > > > > > family. The FEC bits are really close, ACC200 main > > > > > > > > > > > > > addition seems to be FFT acceleration which could > > > > > > > > > > > > > be handled in ACC10x driver based on device ID. > > > > > > > > > > > > > > > > > > > > > > > > > > I think both drivers have to be merged in order to > > > > > > > > > > > > > avoid code duplication. That's how other families > > > > > > > > > > > > > of devices (e.g. i40e) are handled. > > > > > > > > > > > > I haven't seen your reply on this point. Do you > > > > > > > > > > > > confirm you are working on a single driver for ACC > > > > > > > > > > > > family in order to avoid code duplication? > > > > > > > > > > > > > > > > > > > > > > > The implementation is based on distinct ACC100 and > > > > > > > > > > > ACC200 drivers. The 2 > > > > > > > > > > devices are fundamentally different generation, processes > > > > > > > > > > and IP. > > > > > > > > > > > MountBryce is an eASIC device over PCIe while ACC200 is > > > > > > > > > > > an integrated > > > > > > > > > > accelerator on Xeon CPU. > > > > > > > > > > > The actual implementation are not the same, underlying > > > > > > > > > > > IP are all distinct > > > > > > > > > > even if many of the descriptor format have similarities. > > > > > > > > > > > The actual capabilities of the acceleration are > > > > > > > > > > > different and/or new. The workaround and silicon > > > > > > > > > > > errata are also different causing different > > > > > > > > > > limitation and implementation in the driver (see the > > > > > > > > > > serie with ongoing changes for ACC100 in parallel). > > > > > > > > > > > This is fundamentally distinct from ACC101 which was a > > > > > > > > > > > derivative product > > > > > > > > > > from ACC100 and where it made sense to share > > > > > > > > > > implementation > > > > > > between > > > > > > > > > > ACC100 and ACC101. > > > > > > > > > > > So in a nutshell these 2 devices and drivers are 2 > > > > > > > > > > > different beasts and the > > > > > > > > > > intention is to keep them intentionally separate as in > > > > > > > > > > the serie. > > > > > > > > > > > Let me know if unclear, thanks! > > > > > > > > > > Nic, > > > > > > > > > > > > > > > > > > > > I used a similarity checker to compare acc100 and acc200 > > > > > > > > > > > > > > > > > > > > https://urldefense.proofpoint.com/v2/url?u=https- > 3A__dickgrune.com_Programs_similarity- > 5Ftester_&d=DwIBAg&c=nKjWec2b6R0mOyPaz7xtfQ&r=DnL7Si2wl_PRwpZ9TW > ey3eu68gBzn7DkPwuqhd6WNyo&m=m846AfMSeaddoC0hcxp1mHU4LV3jRUpw > P-Ie_41buNb9nACOR5La8n8LEFBCnn4t&s=9dgMzk9UMFLA- > b1EJbi4lK3GG6mNMgOXZRyDZqe00TU&e= > > > > > > > > > > > > > > > > > > > > l=simum.log if [ -f $l ]; then rm $l fi > > > > > > > > > > > > > > > > > > > > sim_c -s -R -o$l -R -p -P -a . > > > > > > > > > > > > > > > > > > > > There results are > > > > > > > > > > > > > > > > > > > > ./acc200/acc200_pf_enum.h consists for 100 % of > > > > > > > > > > ./acc100/acc100_pf_enum.h material > > > > > > > > > > ./acc100/acc100_pf_enum.h consists for 98 % of > > > > > > > > > > ./acc200/acc200_pf_enum.h material > > > > > > > > > > ./acc100/rte_acc100_pmd.h consists for 98 % of > > > > > > > > > > ./acc200/acc200_pmd.h material ./acc200/acc200_vf_enum.h > > > > > > > > > > consists for 95 % of ./acc100/acc100_pf_enum.h material > > > > > > > > > > ./acc200/acc200_pmd.h consists for 92 % of > > > > > > > > > > ./acc100/rte_acc100_pmd.h material > > > > > > > > > > ./acc200/rte_acc200_cfg.h consists for 92 % of > > > > > > > > > > ./acc100/rte_acc100_cfg.h material > > > > > > > > > > ./acc100/rte_acc100_pmd.c consists for 87 % of > > > > > > > > > > ./acc200/rte_acc200_pmd.c material > > > > > > > > > > ./acc100/acc100_vf_enum.h consists for 80 % of > > > > > > > > > > ./acc200/acc200_pf_enum.h material > > > > > > > > > > ./acc200/rte_acc200_pmd.c consists for 78 % of > > > > > > > > > > ./acc100/rte_acc100_pmd.c material > > > > > > > > > > ./acc100/rte_acc100_cfg.h consists for 75 % of > > > > > > > > > > ./acc200/rte_acc200_cfg.h material > > > > > > > > > > > > > > > > > > > > Spot checking the first *pf_enum.h at 100%, these are the > > > > > > > > > > devices' registers, they are the same. > > > > > > > > > > > > > > > > > > > > I raised this similarity issue with 100 vs 101. > > > > > > > > > > > > > > > > > > > > Having multiple copies is difficult to support and should > > > > > > > > > > be avoided. > > > > > > > > > > > > > > > > > > > > For the end user, they should have to use only one > > > > > > > > > > driver. > > > > > > > > > > > > > > > > > > > There are really different IP and do not have the same > > > > > > > > > interface (PCIe/DDR vs > > > > > > > > integrated) and there is big serie of changes which are > > > > > > > > specific to ACC100 coming in parallel. Any workaround, > > > > > > > > optimization would be > > > > > > different. > > > > > > > > > I agree that for the coming serie of integrated accelerator > > > > > > > > > we will use a > > > > > > > > unified driver approach but for that very case that would be > > > > > > > > quite messy to artificially put them within the same PMD. > > > > > > > > > > > > > > > > How is the IP different when 100% of the registers are the > > > > > > > > same ? > > > > > > > > > > > > > > > These are 2 different HW aspects. The base toplevel > > > > > > > configuration registers > > > > > > are kept similar on purpose but the underlying IP are totally > > > > > > different design and implementation. > > > > > > > Even the registers have differences but not visible here, the > > > > > > > actual RDL file > > > > > > would define more specifically these registers bitfields and > > > > > > implementation including which ones are not implemented (but that > > > > > > is proprietary information), and at bbdev level the interface is > > > > > > not some much register based than processing based on data from > > > > > > DMA. > > > > > > > Basically even if there was a common driver, all these would be > > > > > > > duplicated > > > > > > and they are indeed different IP (including different vendors).. > > > > > > > But I agree with the general intent and to have a common driver > > > > > > > for the > > > > > > integrated driver serie (ACC200, ACC300...) now that we are > > > > > > moving away from PCIe/DDR lookaside acceleration and eASIC/FPGA > > > > > > implementation (ACC100/AC101). > > > > > > > > > > > > Looking a little deeper, at how the driver is lays out some of > > > > > > its bitfields and private data by reviewing the > > > > > > > > > > > > ./acc200/acc200_pmd.h consists for 92 % of > > > > > > ./acc100/rte_acc100_pmd.h > > > > > > > > > > > > There are some minor changes to existing reserved bitfields. A > > > > > > new structure for fft. The acc200_device, the private data for > > > > > > the driver, is an exact copy of acc100_device. > > > > > > > > > > > > acc200_pmd.h is the superset and could be used with little > > > > > > changes as a common acc_pmd.h. acc200 is doing everything the > > > > > > acc100 did in a very similar if not exact way, adding the fft > > > > > > feature. > > > > > > > > > > > > Can you point to some portion of this patchset that is so unique > > > > > > that it could not be abstracted to an if-check or function and so > > > > > > requiring this separate, nearly identical driver ? > > > > > > > > > > > You used a similarity checker really, there are actually way more > > > > > relevent differences than what you imply here. With regards to the > > > > > 2 pf_enum.h file, there are many registers that have same or > > > > > similar names but have now different values being mapped hence you > > > > > just cannot use one for the other. Saying that > > > > > "./acc200/acc200_pmd.h consists for 92 % of > > > > > ./acc100/rte_acc100_pmd.h" is just not correct and really > > > > > irrelevant. Just do a diff side by side please and check, that > > > > > should be extremely obvious, that metrics tells more about the > > > > > similarity checker limitation than anything else. Even when using > > > > > a common driver for ACC200/300 they will have distinct register > > > > > enum files being auto-generated and coming from distinct RDL. > > > > > Again just do a diff of these 2 files. I believe you will agree > > > > > that is not relevant for these files to try to artificially merged > > > > > these together. > > > > > > > > > > With regards to the pmd.h, some structure/defines are indeed common > > > > > and could be moved to a common file (for instance turboencoder and > > > > > LDPC encoder which are more vanilla and unlikely to change for > > > > > future product unlike the decoders which have different feature set > > > > > and behaviour; or some 3GPP constant that can be defined once). We > > > > > can definitely change these to put together shared > > > > > structures/defines, but not intending to try to artificially put > > > > > things together with spaghetti code. We would like to keep 3 > > > > > parallel versions of these PMD for 3 different product lines which > > > > > are indeed fundamentally different designs (including different > > > > > workaround required as can be seen on the parallel ACC100 serie > > > > > under review). - one version for FPGA implementation (support for > > > > > N3000, N6000, ...) - one version for eASIC lookaside card > > > > > implementation (ACC100, ACC101, ...) - one version for the > > > > > integrated Xeon accelerators (ACC200, ACC300, ...) > > > > > > > > Some suggestions on refactoring, > > > > > > > > For the registers, have a common file. > > > > > > > > For the shared functionality, ex/ ldpc encoder, break these out to > > > > its own shared file. > > > > > > > > The public interface, see my earlier comments on the documentation, > > > > should be have the same interfaces and the few differences > > > > highlighted. > > > > > > +1 to have common files, and all in a single directory > > > drivers/baseband/acc100/ > > > > Jus to be sure we are aligned, do you mean to have both drivers in the > > same directory, which will share some common files? That's the way I > > would go. > > > > I think the expectation is that the two drivers will diverge in future, so > having separate directories should be ok, even with common files placed in > one directory are shared with another. With meson include paths its pretty > trivial to manage if it's just header files, and even if there are common C > files, there is always the option of using drivers/common if we want to > split them out. As I understand it, right now it's only headers inluding > functions which can be static inline, so simple sharing via include paths > should work fine. > It can be ok to have 2 separate directories, but - is it not possible to have them in same directory say 'acc' for all affiliated devices. Similar to other vendors' devices (cnxk, i40e, mlx). - Can both the devices - acc100 and acc200 coexist? If not, same directory is good enough. - there can be multiple files or directories in 'acc' which can be named appropriately to denote the actual device(acc100/200).
Having cross dependency across different drivers of same type looks a kind of hacking the meson. This was a reason we moved to have a drivers/common/ for some of the drivers. Also including "../acc100/abc.h" does not look appropriate to me. IMO, we should not add unnecessary directories when the code is common and can be managed in a single one. However, technically it is also ok to have 2 separate directories. But, agreeing on this will set a precedence for future next generation devices from the same vendors. It may be a topic of discussion in techboard. -Akhil
