> 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. > > /Bruce
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? 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]? If so, then the GCC version mentioned in the DPDK Getting Started Guide should be corrected accordingly. [1]: https://doc.dpdk.org/guides/linux_gsg/sys_reqs.html#compilation-of-the-dpdk [2]: https://gcc.gnu.org/wiki/C11Status [3]: https://access.redhat.com/solutions/19458 [4]: https://access.redhat.com/support/policy/updates/errata#Life_Cycle_Dates
