[PATCH] mempool: introduce statistics reset function

Morten Brørup
2026-02-23T10:20:58Z

Populating a mempool with objects is accounted for in the statistics.
When analyzing mempool cache statistics, this may distort the data.
In order to simplify mempool cache statistics analysis, a mempool
statistics reset function was added.

Furthermore, details about average burst sizes and mempool cache miss
rates were added to the statistics shown when dumping a mempool.

Signed-off-by: Morten Brørup <mb@smartsharesystems.com>
---
lib/mempool/mempool_trace.h | 7 +++++
lib/mempool/mempool_trace_points.c | 4 +++
lib/mempool/rte_mempool.c | 50 ++++++++++++++++++++++++++++--
lib/mempool/rte_mempool.h | 12 +++++++
4 files changed, 71 insertions(+), 2 deletions(-)

diff --git a/lib/mempool/mempool_trace.h b/lib/mempool/mempool_trace.h
index c595a3116b..23cda1473c 100644
--- a/lib/mempool/mempool_trace.h
+++ b/lib/mempool/mempool_trace.h
@@ -104,6 +104,13 @@ RTE_TRACE_POINT(
rte_trace_point_emit_string(mempool->name);
)

+RTE_TRACE_POINT(
+ rte_mempool_trace_stats_reset,
+ RTE_TRACE_POINT_ARGS(struct rte_mempool *mempool),
+ rte_trace_point_emit_ptr(mempool);
+ rte_trace_point_emit_string(mempool->name);
+)
+
RTE_TRACE_POINT(
rte_mempool_trace_cache_create,
RTE_TRACE_POINT_ARGS(uint32_t size, int socket_id,
diff --git a/lib/mempool/mempool_trace_points.c b/lib/mempool/mempool_trace_points.c
index ec465780f4..8249981502 100644
--- a/lib/mempool/mempool_trace_points.c
+++ b/lib/mempool/mempool_trace_points.c
@@ -60,6 +60,10 @@ RTE_TRACE_POINT_REGISTER(rte_mempool_trace_populate_default,
RTE_TRACE_POINT_REGISTER(rte_mempool_trace_populate_anon,
lib.mempool.populate.anon)

+RTE_EXPORT_EXPERIMENTAL_SYMBOL(__rte_mempool_trace_stats_reset, 26.03)
+RTE_TRACE_POINT_REGISTER(rte_mempool_trace_stats_reset,
+ lib.mempool.stats_reset)
+
RTE_TRACE_POINT_REGISTER(rte_mempool_trace_cache_create,
lib.mempool.cache_create)

diff --git a/lib/mempool/rte_mempool.c b/lib/mempool/rte_mempool.c
index 3042d94c14..ff7d940f91 100644
--- a/lib/mempool/rte_mempool.c
+++ b/lib/mempool/rte_mempool.c
@@ -1049,6 +1049,28 @@ rte_mempool_in_use_count(const struct rte_mempool *mp)
return mp->size - rte_mempool_avail_count(mp);
}

+/* Reset the statistics of a mempool. */
+RTE_EXPORT_EXPERIMENTAL_SYMBOL(rte_mempool_stats_reset, 26.03)
+void
+rte_mempool_stats_reset(struct rte_mempool *mp)
+{
+ RTE_ASSERT(mp != NULL);
+
+#ifdef RTE_LIBRTE_MEMPOOL_STATS
+ memset(&mp->stats, 0, sizeof(mp->stats));
+ if (mp->cache_size != 0) {
+ for (unsigned int lcore_id = 0; lcore_id < RTE_MAX_LCORE; lcore_id++) {
+ memset(&mp->local_cache[lcore_id].stats, 0,
+ sizeof(mp->local_cache[lcore_id].stats));
+ }
+ }
+
+ rte_mempool_trace_stats_reset(mp);
+#else
+ RTE_SET_USED(mp);
+#endif
+}
+
/* dump the cache status */
static unsigned
rte_mempool_dump_cache(FILE *f, const struct rte_mempool *mp)
@@ -1327,10 +1349,34 @@ rte_mempool_dump(FILE *f, struct rte_mempool *mp)
fprintf(f, " get_fail_bulk=%"PRIu64"\n", sum.get_fail_bulk);
fprintf(f, " get_fail_objs=%"PRIu64"\n", sum.get_fail_objs);
if (info.contig_block_size > 0) {
- fprintf(f, " get_success_blks=%"PRIu64"\n",
- sum.get_success_blks);
+ fprintf(f, " get_success_blks=%"PRIu64"\n", sum.get_success_blks);
fprintf(f, " get_fail_blks=%"PRIu64"\n", sum.get_fail_blks);
}
+ fprintf(f, " avg objs/bulk put=%#Lf, get=%#Lf, get_fail=%#Lf\n",
+ sum.put_bulk != 0 ? (long double)sum.put_objs / sum.put_bulk : 0,
+ sum.get_success_bulk != 0 ?
+ (long double)sum.get_success_objs / sum.get_success_bulk : 0,
+ sum.get_fail_bulk != 0 ?
+ (long double)sum.get_fail_objs / sum.get_fail_bulk : 0);
+ fprintf(f, " avg common_pool objs/bulk put=%#Lf, get=%#Lf\n",
+ sum.put_common_pool_bulk != 0 ?
+ (long double)sum.put_common_pool_objs / sum.put_common_pool_bulk : 0,
+ sum.get_common_pool_bulk != 0 ?
+ (long double)sum.get_common_pool_objs / sum.get_common_pool_bulk : 0);
+ fprintf(f, " avg cache miss rate put_objs=%s%#Lf, get_objs=%s%#Lf\n",
+ sum.put_common_pool_objs != 0 ? "1/" : "",
+ sum.put_common_pool_objs != 0 ?
+ (long double)sum.put_objs / sum.put_common_pool_objs : 0,
+ sum.get_common_pool_objs != 0 ? "1/" : "",
+ sum.get_common_pool_objs != 0 ?
+ (long double)sum.get_success_objs / sum.get_common_pool_objs : 0);
+ fprintf(f, " avg cache miss rate put_bulk=%s%#Lf, get_bulk=%s%#Lf\n",
+ sum.put_common_pool_bulk != 0 ? "1/" : "",
+ sum.put_common_pool_bulk != 0 ?
+ (long double)sum.put_bulk / sum.put_common_pool_bulk : 0,
+ sum.get_common_pool_bulk != 0 ? "1/" : "",
+ sum.get_common_pool_bulk != 0 ?
+ (long double)sum.get_success_bulk / sum.get_common_pool_bulk : 0);
#else
fprintf(f, " no statistics available\n");
#endif
diff --git a/lib/mempool/rte_mempool.h b/lib/mempool/rte_mempool.h
index 1144dca58a..1aea1789e9 100644
--- a/lib/mempool/rte_mempool.h
+++ b/lib/mempool/rte_mempool.h
@@ -1288,6 +1288,18 @@ uint32_t rte_mempool_obj_iter(struct rte_mempool *mp,
uint32_t rte_mempool_mem_iter(struct rte_mempool *mp,
rte_mempool_mem_cb_t *mem_cb, void *mem_cb_arg);

+/**
+ * @warning
+ * @b EXPERIMENTAL: This API may change, or be removed, without prior notice.
+ *
+ * Reset the statistics of a mempool.
+ *
+ * @param mp
+ * A pointer to the mempool structure.
+ */
+__rte_experimental
+void rte_mempool_stats_reset(struct rte_mempool *mp);
+
/**
* Dump the status of the mempool to a file.
*
--
2.43.0