13/10/2022 09:12, Pavan Nikhilesh Bhagavatula: > From: Morten Brørup <m...@smartsharesystems.com> > > +TO: rawdev maintainers, regexdev maintainers > > > > > From: Thomas Monjalon [mailto:tho...@monjalon.net] > > > Sent: Wednesday, 12 October 2022 22.44 > > > > > > 12/10/2022 18:47, Jerin Jacob: > > > > On Wed, Oct 12, 2022 at 9:58 PM Thomas Monjalon > > <tho...@monjalon.net> > > > wrote: > > > > > > > > > > 12/10/2022 18:16, Jerin Jacob: > > > > > > On Wed, Oct 12, 2022 at 9:05 PM Morten Brørup > > > <m...@smartsharesystems.com> wrote: > > > > > > > > > > > > > > > From: Thomas Monjalon [mailto:tho...@monjalon.net] > > > > > > > > Sent: Wednesday, 12 October 2022 17.13 > > > > > > > > > > > > > > > > 12/10/2022 14:14, Van Haaren, Harry: > > > > > > > > > From: Morten Brørup <m...@smartsharesystems.com> > > > > > > > > > > From: Van Haaren, Harry > > > [mailto:harry.van.haa...@intel.com] > > > > > > > > > > > From: Jerin Jacob <jerinjac...@gmail.com> > > > > > > > > > > > > On Wed, Oct 12, 2022 at 1:40 PM Morten Brørup wrote: > > > > > > > > > > > > > > > > > > > > > > > > > > Hi Jerin (eventdev maintainer), > > > > > > > > > > > > > > > > > > > > > > > > + harry.van.haa...@intel.com as the changes in > > > > > > > > drivers/event/sw. > > > > > > > > > > > > > > > > > > > > > > Thanks Jerin. > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > While looking into bug #1101 [1], I noticed a mix > > > of unsigned > > > > > > > > int > > > > > > > > > > > and uint32_t in > > > > > > > > > > > > the test code, which will fail on 64-bit big endian > > > CPUs. > > > > > > > > > > > > > > > > > > > > > > Aha; that we can fix. I am curious why this isn't found > > > in > > > > > > > > CI/reported > > > > > > > > > > > before. > > > > > > > > > > > > > > > > > > > > We probably don't test any 64-bit *big endian* > > > architectures. Just > > > > > > > > a guess. > > > > > > > > > > > > > > > > > > Seems so yes. > > > > > > > > > > > > > > > > > > > > > > Specifically, rte_event_dev_xstats_reset() is > > > called with the > > > > > > > > "ids" > > > > > > > > > > > parameter > > > > > > > > > > > > pointing to an unsigned int [2], but that parameter > > > is a > > > > > > > > pointer to > > > > > > > > > > > an uint32_t. > > > > > > > > > > > > > > > > > > > > > > > > > > I think the type of the ids array parameter to > > > > > > > > > > > rte_event_dev_xstats_reset() should > > > > > > > > > > > > be changed to unsigned int array, like in the other > > > > > > > > > > > rte_event_dev_xxx() functions. > > > > > > > > > > > > > > > > > > > > > > In this case, we have the option to change the type of > > > a variable > > > > > > > > in a > > > > > > > > > > > test-case, or change API and cause API/ABI breakage. > > > > > > > > > > > > > > > > > > > > Well.. yes, but I would phrase that last option: Change > > > the > > > > > > > > API/ABI, so related > > > > > > > > > > functions consistently use the same type for the same > > > variable, > > > > > > > > instead of randomly > > > > > > > > > > mixing uint64_t, uint32_t and unsigned int, depending on > > > function. > > > > > > > > > > > > > > > > > > Aah ok; I see your point now; there is inconsistent usage > > > of > > > > > > > > uint32_t/unsigned int > > > > > > > > > between the Eventdev APIs itself. Agree this is sub- > > > optimal, and > > > > > > > > would have been > > > > > > > > > nice to have spotted before the Eventdev API was > > > stabilized. > > > > > > > > > > > > > > > > > > > > > > > > > > > > Unfortunately, these functions are not marked > > > experimental, so > > > > > > > > breaking API/ABI is > > > > > > > > > > hard to do. :-( > > > > > > > > > > > > > > > > > > Agreed again. > > > > > > > > > > > > > > > > 22.11 is a breaking release, > > > > > > > > and changing type in the API is not much impactful, > > > > > > > > so that's something you can change now, > > > > > > > > or be quiet forever :) > > > > > > > > > > > > > > Question: > > > > > > > 1. Only change the "xstats id" type in the one eventdev > > > function, which deviates from other eventdev functions, or > > > > > > > 2. Change the "xstats id" type for all xstats functions across > > > all device types, for consistency across device types? > > > > > > > > > > > > > > If 2, then what would be a good type? > > > > > > > > > > > > +1 for second option and the type as uint32_t > > > > > > > > > > > > > > > > > > > > Ethdev uses uint64_t for xstats id, and (speaking without > > > knowledge about its internals) that seems like overkill to me. Arrays > > > of these are being used, so size does matter. > > > > > > > > > > uint64_t is not overkill if you consider having stats per queue > > > with a predictable scheme. > > > > > That's an improvement I would like to work on, > > > > > > > > You mean to use a bitmask hence uint64_t. > > > > Currently it is mapped as arrays so 2^64 stats may not be needed. > > > > > > > > No strong opinion, I was just curious to understand "stats per queue > > > > with a predictable scheme" and how uint64_t helps with that. > > > > > > Yes I mean some bits are used for the queue number. > > > Something like in slide 11 of this presentation: > > > https://urldefense.proofpoint.com/v2/url?u=http- > > 3A__fast.dpdk.org_events_slides_DPDK-2D2019-2D09-2DEthernet- > > 5FStatistics.pdf&d=DwIFAw&c=nKjWec2b6R0mOyPaz7xtfQ&r=1cjuAHrGh74 > > 5jHNmj2fD85sUMIJ2IPIDsIJzo6FN6Z0&m=ApdcbroZzSNlcY1t4c8iv9HZk6YSJOA > > Hpg93zuyIEEWa6xkViBTdoCA3iir_FCtW&s=wEMA0lnyrTmxmmDINhzOagGvV > > Z3TcIrzfK5NbJHafdM&e= > > > > With this presentation in mind, I strongly agree with Thomas that uint64_t > > is > > the best choice of type for xstats id. > > > > A quick search shows that both eventdev and rawdev use "unsigned int", > > except rte_event_dev_xstats_reset() and rte_rawdev_xstats_reset(), which > > both use uint32_t. And regexdev uses uint16_t. Other device APIs don't have > > xstats. > > Harry, > Are you working on a patch for this change? If not I will do it. > > Thomas, > Are you ok to break the ABI without deprication notice i.e. make ID as u64 > for eventdev?
Yes, it is only increasing size of function parameters, right? The only problematic part is that the application must pass a pointer of the right size, meaning some application code change. It would be an exception in the process, so I am Cc'ing the techboard for more opinions.
