On Wed, 20 Mar 2024 14:05:56 -0700 Tyler Retzlaff <roret...@linux.microsoft.com> wrote:
> MSVC struct packing is not compatible with GCC provide a macro that can > be used to push existing pack value and sets packing to 1-byte. The > existing __rte_packed macro is then used to restore the pack value > prior to the push. > > Instead of providing macros exclusively for MSVC and for GCC the > existing macro is deliberately utilized to trigger a warning if no > existing packing has been pushed allowing easy identification of > locations where the __rte_msvc_pack is missing. > > I've decided to only add the macro to packed structs that are built > for Windows. It seems there is little value in adding the macro tree > wide and if new code arrives that is built on Windows the __rte_packed > will flag where the preamble macro is required. > Why is packed used so many places in DPDK? Packed should be reserved for things like network protocols with unaligned fields. Many of these structure have no holes and are naturally packed. Adding packed attribute unnecessarily can generate poor code on architectures that do not support unaligned access.
