06/01/2023 19:58, Tyler Retzlaff: > On Fri, Jan 06, 2023 at 02:40:59PM +0100, Thomas Monjalon wrote: > > 06/01/2023 13:41, Morten Brørup: > > > > From: Bruce Richardson [mailto:bruce.richard...@intel.com] > > > > Sent: Friday, 6 January 2023 12.48 > > > > > > > > On Thu, Jan 05, 2023 at 04:32:40PM -0800, Stephen Hemminger wrote: > > > > > On Thu, 5 Jan 2023 09:21:18 -0800 > > > > > Tyler Retzlaff <roret...@linux.microsoft.com> wrote: > > > > > > > > > > > On Thu, Jan 05, 2023 at 10:01:31AM +0100, Thomas Monjalon wrote: > > > > > > > 05/01/2023 08:09, Morten Brørup: > > > > > > > > > From: Tyler Retzlaff [mailto:roret...@linux.microsoft.com] > > > > > > > > > +/** > > > > > > > > > + * @warning > > > > > > > > > + * @b EXPERIMENTAL: this API may change, or be removed, > > > > without prior > > > > > > > > > notice > > > > > > > > > + * > > > > > > > > > + * Get the count of leading 0-bits in v. > > > > > > > > > + * > > > > > > > > > + * @param v > > > > > > > > > + * The value. > > > > > > > > > + * @return > > > > > > > > > + * The count of leading zero bits. > > > > > > > > > + */ > > > > > > > > > +__rte_experimental > > > > > > > > > +static inline unsigned int > > > > > > > > > +rte_clzl(unsigned long v) > > > > > > > > > > > > > > > > Don't use l (long) and ll (long long) for names (and types), > > > > use explicit bit lengths, 32 and 64. > > > > > > > > > > > > > > > > E.g.: rte_clz32(uint32_t v) > > > > > > > > > > > > > > I agree on using numbers. > > > > > > > > > > > > > > > > > > > love the idea, fewer functions too. > > > > > > > > > > > > though it is a shame we cannot adopt C11 standard because we could > > > > just > > > > > > do away with the bit suffixes entirely. > > > > > > > > > > We could but the project needs to support older RHEL releases > > > > > which have older tool sets. Though probably this is moot point given > > > > > how much meson seems to change. > > > > > > > > True, though meson tends to be a bit easier to update than GCC on a > > > > system > > > > - no "pip3 install --upgrade gcc", sadly :-) > > > > > > > > If we can't go all the way to C11 support, how about at least going to > > > > C99 > > > > support? As far as I know DPDK has never updated its minimum C-standard > > > > version, and it might be a good idea to start the process of doing so, > > > > even > > > > if it is a baby step. > > > > I am in favor of this baby step: define -std=c99 porject-wise > > and see what are the effects during the year. > > > > > > > The DPDK Getting Started Guide [1] says: > > > > > > "Required Tools and Libraries: > > > [...] > > > a supported C compiler such as gcc (version 4.9+)" > > > > > > GCC version 4.9 supports C11 [2]: > > > "GCC 4.9 Changes: "ISO C11 support is now at a similar level of > > > completeness to ISO C99 support [...]" > > > > > > So why are we not going to support C11? > > > > We should make a plan to switch to C11 during next year. > > > > > > > Probably because of RHEL 7, which only provides GCC 4.8 [3]. > > > > > > RHEL 7 was released for GA on June 10, 2014 [4]. If someone has a server > > > with a nine year old distro still used in production, it is probably > > > because it is running some legacy application, which is difficult to get > > > up and running on a newer distro. Partial conclusion: RHEL 7 is probably > > > still widely used in production. > > > > > > However, I have a hard time understanding why anyone would build and/or > > > deploy a brand new DPDK application (based on DPDK 23.03) on such a > > > server. Can someone please justify this? > > > > > > Are we really going to postpone C11 support in DPDK until June 30, 2026, > > > when RHEL 7 ends its Extended Life Cycle Support [4]? > > > > RHEL does its own choices to support old software for long. > > Upstream development should move forward. > > > > > > > If so, then the GCC version mentioned in the DPDK Getting Started Guide > > > should be corrected accordingly. > > > > No let's keep GCC 4.9 as a minimum for now. > > If needed we could upgrade it later. > > but i think the point Morten is making is that RHEL 7 gcc is 4.8 and > therefore we implicitly no longer support it if we document requiring > gcc 4.9.
Yes I got it. I think everything in DPDK works on RHEL 7 today, but I believe RHEL 7 is not a strong requirement anymore for the mainline. Asking for confirmation here. > so i think the way to do this is through clarification at the next > release / ltsc release. starting with dpdk 23.xx will require > compiler conforming to standard X and optional features / annexes from > standard X. anyone building applications targeting that version of dpdk > release will need a conforming implementation. > > from there we just need to take care not to backport any code to > stable branches that depend on standard features that exceed the > requirements documented for that release. We could even start testing C99 requirement in 23.03 I think.
