On Wed, Feb 26, 2025 at 03:59:22PM +0000, Morten Brørup wrote: > The comparisons lcore_id < RTE_MAX_LCORE and lcore_id != LCORE_ID_ANY are > equivalent, but the latter compiles to fewer bytes of code space. > Similarly for lcore_id >= RTE_MAX_LCORE and lcore_id == LCORE_ID_ANY. > > The rte_mempool_get_ops() function is also used in the fast path, so > RTE_VERIFY() was replaced by RTE_ASSERT(). > > Compilers implicitly consider comparisons of variable == 0 likely, so > unlikely() was added to the check for no mempool cache (mp->cache_size == > 0) in the rte_mempool_default_cache() function. > > The rte_mempool_do_generic_put() function for adding objects to a mempool > was refactored as follows: > - The comparison for the request itself being too big, which is considered > unlikely, was moved down and out of the code path where the cache has > sufficient room for the added objects, which is considered the most > likely code path. > - Added __rte_assume() about the cache length, size and threshold, for > compiler optimization when "n" is compile time constant. > - Added __rte_assume() about "ret" being zero, so other functions using > the value returned by this function can be potentially optimized by the > compiler; especially when it merges multiple sequential code paths of > inlined code depending on the return value being either zero or > negative. > - The refactored source code (with comments) made the separate comment > describing the cache flush/add algorithm superfluous, so it was removed. > > A few more likely()/unlikely() were added. > > A few comments were improved for readability. > > Some assertions, RTE_ASSERT(), were added. Most importantly to assert that > the return values of the mempool drivers' enqueue and dequeue operations > are API compliant, i.e. 0 (for success) or negative (for failure), and > never positive. > > Signed-off-by: Morten Brørup <m...@smartsharesystems.com> > --- > lib/mempool/rte_mempool.h | 67 ++++++++++++++++++++++----------------- > 1 file changed, 38 insertions(+), 29 deletions(-) > Is there any measurable performance change with these modifications?
/Bruce
