The current way has a few problems:
- if cache->len < n, we copy our elements into the cache first, then
into obj_table, that's unnecessary
- if n >= cache_size (or the backfill fails), and we can't fulfil the
request from the ring alone, we don't try to combine with the cache
- if refill fails, we don't return anything, even if the ring has enough
for our request
This patch rewrites it severely:
- at the first part of the function we only try the cache if cache->len < n
- otherwise take our elements straight from the ring
- if that fails but we have something in the cache, try to combine them
- the refill happens at the end, and its failure doesn't modify our return
value
Signed-off-by: Zoltan Kiss <zoltan.kiss at linaro.org>
---
lib/librte_mempool/rte_mempool.h | 63 +++++++++++++++++++++++++---------------
1 file changed, 39 insertions(+), 24 deletions(-)
diff --git a/lib/librte_mempool/rte_mempool.h b/lib/librte_mempool/rte_mempool.h
index a8054e1..896946c 100644
--- a/lib/librte_mempool/rte_mempool.h
+++ b/lib/librte_mempool/rte_mempool.h
@@ -948,34 +948,14 @@ __mempool_get_bulk(struct rte_mempool *mp, void
**obj_table,
unsigned lcore_id = rte_lcore_id();
uint32_t cache_size = mp->cache_size;
- /* cache is not enabled or single consumer */
+ cache = &mp->local_cache[lcore_id];
+ /* cache is not enabled or single consumer or not enough */
if (unlikely(cache_size == 0 || is_mc == 0 ||
- n >= cache_size || lcore_id >= RTE_MAX_LCORE))
+ cache->len < n || lcore_id >= RTE_MAX_LCORE))
goto ring_dequeue;
- cache = &mp->local_cache[lcore_id];
cache_objs = cache->objs;
- /* Can this be satisfied from the cache? */
- if (cache->len < n) {
- /* No. Backfill the cache first, and then fill from it */
- uint32_t req = n + (cache_size - cache->len);
-
- /* How many do we require i.e. number to fill the cache + the
request */
- ret = rte_ring_mc_dequeue_bulk(mp->ring,
&cache->objs[cache->len], req);
- if (unlikely(ret < 0)) {
- /*
- * In the offchance that we are buffer constrained,
- * where we are not able to allocate cache + n, go to
- * the ring directly. If that fails, we are truly out of
- * buffers.
- */
- goto ring_dequeue;
- }
-
- cache->len += req;
- }
-
/* Now fill in the response ... */
for (index = 0, len = cache->len - 1; index < n; ++index, len--,
obj_table++)
*obj_table = cache_objs[len];
@@ -984,7 +964,8 @@ __mempool_get_bulk(struct rte_mempool *mp, void **obj_table,
__MEMPOOL_STAT_ADD(mp, get_success, n);
- return 0;
+ ret = 0;
+ goto cache_refill;
ring_dequeue:
#endif /* RTE_MEMPOOL_CACHE_MAX_SIZE > 0 */
@@ -995,11 +976,45 @@ ring_dequeue:
else
ret = rte_ring_sc_dequeue_bulk(mp->ring, obj_table, n);
+#if RTE_MEMPOOL_CACHE_MAX_SIZE > 0
+ if (ret < 0 && is_mc == 1 && cache->len > 0) {
+ uint32_t req = n - cache->len;
+
+ ret = rte_ring_mc_dequeue_bulk(mp->ring, obj_table, req);
+ if (ret == 0) {
+ cache_objs = cache->objs;
+ obj_table += req;
+ for (index = 0; index < cache->len;
+ ++index, ++obj_table)
+ *obj_table = cache_objs[index];
+ cache->len = 0;
+ }
+ }
+#endif /* RTE_MEMPOOL_CACHE_MAX_SIZE > 0 */
+
if (ret < 0)
__MEMPOOL_STAT_ADD(mp, get_fail, n);
else
__MEMPOOL_STAT_ADD(mp, get_success, n);
+#if RTE_MEMPOOL_CACHE_MAX_SIZE > 0
+cache_refill:
+ /* If previous dequeue was OK and we have less than n, start refill */
+ if (ret == 0 && cache_size > 0 && cache->len < n) {
+ uint32_t req = cache_size - cache->len;
+
+ cache_objs = cache->objs;
+ ret = rte_ring_mc_dequeue_bulk(mp->ring,
+ &cache->objs[cache->len],
+ req);
+ if (likely(ret == 0))
+ cache->len += req;
+ else
+ /* Don't spoil the return value */
+ ret = 0;
+ }
+#endif /* RTE_MEMPOOL_CACHE_MAX_SIZE > 0 */
+
return ret;
}
--
1.9.1
