On Wed, 8 Mar 2017 12:06:54 +0000, Bruce Richardson <bruce.richard...@intel.com> wrote: > On Wed, Mar 08, 2017 at 11:49:06AM +0100, Olivier MATZ wrote: > > On Thu, 23 Feb 2017 17:24:05 +0000, Bruce Richardson > > <bruce.richard...@intel.com> wrote: > > > We can write a single common function for head manipulation for enq > > > and a common one for deq, allowing us to have a single worker function > > > for enq and deq, rather than two of each. Update all other inline > > > functions to use the new functions. > > > > > > Signed-off-by: Bruce Richardson <bruce.richard...@intel.com> > > > --- > > > lib/librte_ring/rte_ring.c | 4 +- > > > lib/librte_ring/rte_ring.h | 328 > > > ++++++++++++++++++++------------------------- > > > 2 files changed, 149 insertions(+), 183 deletions(-) > > > > > > > [...] > > > > > +static inline __attribute__((always_inline)) unsigned int > > > +__rte_ring_do_enqueue(struct rte_ring *r, void * const *obj_table, > > > + unsigned int n, enum rte_ring_queue_behavior behavior, > > > + int is_sp, unsigned int *free_space) > > > { > > > - uint32_t prod_head, cons_tail; > > > - uint32_t prod_next, free_entries; > > > - uint32_t mask = r->mask; > > > - > > > - prod_head = r->prod.head; > > > - cons_tail = r->cons.tail; > > > - /* The subtraction is done between two unsigned 32bits value > > > - * (the result is always modulo 32 bits even if we have > > > - * prod_head > cons_tail). So 'free_entries' is always between 0 > > > - * and size(ring)-1. */ > > > - free_entries = mask + cons_tail - prod_head; > > > - > > > - /* check that we have enough room in ring */ > > > - if (unlikely(n > free_entries)) > > > - n = (behavior == RTE_RING_QUEUE_FIXED) ? 0 : free_entries; > > > + uint32_t prod_head, prod_next; > > > + uint32_t free_entries; > > > > > > + n = __rte_ring_move_prod_head(r, is_sp, n, behavior, > > > + &prod_head, &prod_next, &free_entries); > > > if (n == 0) > > > goto end; > > > > > > - > > > - prod_next = prod_head + n; > > > - r->prod.head = prod_next; > > > - > > > - /* write entries in ring */ > > > ENQUEUE_PTRS(); > > > rte_smp_wmb(); > > > > > > + /* > > > + * If there are other enqueues in progress that preceded us, > > > + * we need to wait for them to complete > > > + */ > > > + while (unlikely(r->prod.tail != prod_head)) > > > + rte_pause(); > > > + > > > > I'd say this part should not be done in case is_sp == 1. > > Since it is sometimes a constant arg in an inline func, it may be better > > to add the if (is_sp == 0). > > > > [...] > > > > Yes, it's an unnecessary check. However, having it in place for the sp > case made no performance difference in my test, so I decided to keep > the code shorter by avoiding an additional branch. If there is a > performance hit I'll remove it, but I would rather not add more branches > to the code in the absense of a real impact to not having them.
Ok. Maybe it's worth checking the numbers given by the unit test. Olivier