Hi Morten,
Few nits, see below.
Also I still think we do need a test case for _zc_get_ before
accepting it in the mainline.
With that in place:
Acked-by: Konstantin Ananyev <konstantin.v.anan...@yandex.ru>
Zero-copy access to mempool caches is beneficial for PMD performance, and
must be provided by the mempool library to fix [Bug 1052] without a
performance regression.
[Bug 1052]: https://bugs.dpdk.org/show_bug.cgi?id=1052
Bugzilla ID: 1052
v5:
* Bugfix: Compare zero-copy get request to the cache size instead of the
flush threshold; otherwise refill could overflow the memory allocated
for the cache. (Andrew)
* Split the zero-copy put function into an internal function doing the
work, and a public function with trace.
* Avoid code duplication by rewriting rte_mempool_do_generic_put() to use
the internal zero-copy put function. (Andrew)
* Corrected the return type of rte_mempool_cache_zc_put_bulk() from void *
to void **; it returns a pointer to an array of objects.
* Fix coding style: Add missing curly brackets. (Andrew)
v4:
* Fix checkpatch warnings.
v3:
* Bugfix: Respect the cache size; compare to the flush threshold instead
of RTE_MEMPOOL_CACHE_MAX_SIZE.
* Added 'rewind' function for incomplete 'put' operations. (Konstantin)
* Replace RTE_ASSERTs with runtime checks of the request size.
Instead of failing, return NULL if the request is too big. (Konstantin)
* Modified comparison to prevent overflow if n is really huge and len is
non-zero.
* Updated the comments in the code.
v2:
* Fix checkpatch warnings.
* Fix missing registration of trace points.
* The functions are inline, so they don't go into the map file.
v1 changes from the RFC:
* Removed run-time parameter checks. (Honnappa)
This is a hot fast path function; requiring correct application
behaviour, i.e. function parameters must be valid.
* Added RTE_ASSERT for parameters instead.
Code for this is only generated if built with RTE_ENABLE_ASSERT.
* Removed fallback when 'cache' parameter is not set. (Honnappa)
* Chose the simple get function; i.e. do not move the existing objects in
the cache to the top of the new stack, just leave them at the bottom.
* Renamed the functions. Other suggestions are welcome, of course. ;-)
* Updated the function descriptions.
* Added the functions to trace_fp and version.map.
Signed-off-by: Morten Brørup <m...@smartsharesystems.com>
---
lib/mempool/mempool_trace_points.c | 9 ++
lib/mempool/rte_mempool.h | 237 +++++++++++++++++++++++++----
lib/mempool/rte_mempool_trace_fp.h | 23 +++
lib/mempool/version.map | 5 +
4 files changed, 245 insertions(+), 29 deletions(-)
diff --git a/lib/mempool/mempool_trace_points.c
b/lib/mempool/mempool_trace_points.c
index 4ad76deb34..83d353a764 100644
--- a/lib/mempool/mempool_trace_points.c
+++ b/lib/mempool/mempool_trace_points.c
@@ -77,3 +77,12 @@ RTE_TRACE_POINT_REGISTER(rte_mempool_trace_ops_free,
RTE_TRACE_POINT_REGISTER(rte_mempool_trace_set_ops_byname,
lib.mempool.set.ops.byname)
+
+RTE_TRACE_POINT_REGISTER(rte_mempool_trace_cache_zc_put_bulk,
+ lib.mempool.cache.zc.put.bulk)
+
+RTE_TRACE_POINT_REGISTER(rte_mempool_trace_cache_zc_put_rewind,
+ lib.mempool.cache.zc.put.rewind)
+
+RTE_TRACE_POINT_REGISTER(rte_mempool_trace_cache_zc_get_bulk,
+ lib.mempool.cache.zc.get.bulk)
diff --git a/lib/mempool/rte_mempool.h b/lib/mempool/rte_mempool.h
index 9f530db24b..5efd3c2b5b 100644
--- a/lib/mempool/rte_mempool.h
+++ b/lib/mempool/rte_mempool.h
@@ -47,6 +47,7 @@
#include <rte_ring.h>
#include <rte_memcpy.h>
#include <rte_common.h>
+#include <rte_errno.h>
#include "rte_mempool_trace_fp.h"
@@ -1346,6 +1347,197 @@ rte_mempool_cache_flush(struct rte_mempool_cache *cache,
cache->len = 0;
}
+/**
+ * @internal used by rte_mempool_cache_zc_put_bulk() and
rte_mempool_do_generic_put().
+ *
+ * Zero-copy put objects in a user-owned mempool cache backed by the specified
mempool.
+ *
+ * @param cache
+ * A pointer to the mempool cache.
+ * @param mp
+ * A pointer to the mempool.
+ * @param n
+ * The number of objects to be put in the mempool cache.
+ * @return
+ * The pointer to where to put the objects in the mempool cache.
+ * NULL if the request itself is too big for the cache, i.e.
+ * exceeds the cache flush threshold.
+ */
+static __rte_always_inline void **
+__rte_mempool_cache_zc_put_bulk(struct rte_mempool_cache *cache,
+ struct rte_mempool *mp,
+ unsigned int n)
+{
+ void **cache_objs;
+
+ RTE_ASSERT(cache != NULL);
+ RTE_ASSERT(mp != NULL);
+
+ if (n <= cache->flushthresh - cache->len) {
+ /*
+ * The objects can be added to the cache without crossing the
+ * flush threshold.
+ */
+ cache_objs = &cache->objs[cache->len];
+ cache->len += n;
+ } else if (likely(n <= cache->flushthresh)) {
+ /*
+ * The request itself fits into the cache.
+ * But first, the cache must be flushed to the backend, so
+ * adding the objects does not cross the flush threshold.
+ */
+ cache_objs = &cache->objs[0];
+ rte_mempool_ops_enqueue_bulk(mp, cache_objs, cache->len);
+ cache->len = n;
+ } else {
+ /* The request itself is too big for the cache. */
+ return NULL;
+ }
+
+ RTE_MEMPOOL_CACHE_STAT_ADD(cache, put_bulk, 1);
+ RTE_MEMPOOL_CACHE_STAT_ADD(cache, put_objs, n);
+
+ return cache_objs;
+}
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: This API may change, or be removed, without prior notice.
+ *
+ * Zero-copy put objects in a user-owned mempool cache backed by the specified
mempool.
+ *
+ * @param cache
+ * A pointer to the mempool cache.
+ * @param mp
+ * A pointer to the mempool.
+ * @param n
+ * The number of objects to be put in the mempool cache.
+ * @return
+ * The pointer to where to put the objects in the mempool cache.
+ * NULL if the request itself is too big for the cache, i.e.
+ * exceeds the cache flush threshold.
+ */
+__rte_experimental
+static __rte_always_inline void **
+rte_mempool_cache_zc_put_bulk(struct rte_mempool_cache *cache,
+ struct rte_mempool *mp,
+ unsigned int n)
+{
+ RTE_ASSERT(cache != NULL);
+ RTE_ASSERT(mp != NULL);
+
+ rte_mempool_trace_cache_zc_put_bulk(cache, mp, n);
+ return __rte_mempool_cache_zc_put_bulk(cache, mp, n);
+}
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: This API may change, or be removed, without prior notice.
+ *
+ * Zero-copy un-put objects in a user-owned mempool cache.
+ *
+ * @param cache
+ * A pointer to the mempool cache.
+ * @param n
+ * The number of objects not put in the mempool cache after calling
+ * rte_mempool_cache_zc_put_bulk().
+ */
+__rte_experimental
+static __rte_always_inline void
+rte_mempool_cache_zc_put_rewind(struct rte_mempool_cache *cache,
+ unsigned int n)
+{
+ RTE_ASSERT(cache != NULL);
+ RTE_ASSERT(n <= cache->len);
+
+ rte_mempool_trace_cache_zc_put_rewind(cache, n);
+
+ cache->len -= n;
+
+ RTE_MEMPOOL_CACHE_STAT_ADD(cache, put_objs, (int)-n);
+}
+
+/**
+ * @warning
+ * @b EXPERIMENTAL: This API may change, or be removed, without prior notice.
+ *
+ * Zero-copy get objects from a user-owned mempool cache backed by the
specified mempool.
+ *
+ * @param cache
+ * A pointer to the mempool cache.
+ * @param mp
+ * A pointer to the mempool.
+ * @param n
+ * The number of objects to prefetch into the mempool cache.
Why not 'get' instead of 'prefetch'?
+ * @return
+ * The pointer to the objects in the mempool cache.
+ * NULL on error; i.e. the cache + the pool does not contain 'n' objects.
+ * With rte_errno set to the error code of the mempool dequeue function,
+ * or EINVAL if the request itself is too big for the cache, i.e.
+ * exceeds the cache flush threshold.
+ */
+__rte_experimental
+static __rte_always_inline void *
+rte_mempool_cache_zc_get_bulk(struct rte_mempool_cache *cache,
+ struct rte_mempool *mp,
+ unsigned int n)
+{
+ unsigned int len, size;
+
+ RTE_ASSERT(cache != NULL);
+ RTE_ASSERT(mp != NULL);
+
+ rte_mempool_trace_cache_zc_get_bulk(cache, mp, n);
+
+ len = cache->len;
+ size = cache->size;
+
+ if (n <= len) {
+ /* The request can be satisfied from the cache as is. */
+ len -= n;
+ } else if (likely(n <= size)) {
+ /*
+ * The request itself can be satisfied from the cache.
+ * But first, the cache must be filled from the backend;
+ * fetch size + requested - len objects.
+ */
+ int ret;
+
+ ret = rte_mempool_ops_dequeue_bulk(mp, &cache->objs[len], size
+ n - len);
+ if (unlikely(ret < 0)) {
+ /*
+ * We are buffer constrained.
+ * Do not fill the cache, just satisfy the request.
+ */
+ ret = rte_mempool_ops_dequeue_bulk(mp,
&cache->objs[len], n - len);
+ if (unlikely(ret < 0)) {
+ /* Unable to satisfy the request. */
+
+ RTE_MEMPOOL_STAT_ADD(mp, get_fail_bulk, 1);
+ RTE_MEMPOOL_STAT_ADD(mp, get_fail_objs, n);
+
+ rte_errno = -ret;
+ return NULL;
+ }
+
+ len = 0;
+ } else {
+ len = size;
+ }
+ } else {
+ /* The request itself is too big for the cache. */
+ rte_errno = EINVAL;
+ return NULL;
+ }
+
+ cache->len = len;
+
+ RTE_MEMPOOL_CACHE_STAT_ADD(cache, get_success_bulk, 1);
+ RTE_MEMPOOL_CACHE_STAT_ADD(cache, get_success_objs, n);
+
+ return &cache->objs[len];
+}
+
/**
* @internal Put several objects back in the mempool; used internally.
* @param mp
@@ -1364,32 +1556,25 @@ rte_mempool_do_generic_put(struct rte_mempool *mp, void
* const *obj_table,
{
void **cache_objs;
- /* No cache provided */
- if (unlikely(cache == NULL))
- goto driver_enqueue;
+ /* No cache provided? */
+ if (unlikely(cache == NULL)) {
+ /* Increment stats now, adding in mempool always succeeds. */
+ RTE_MEMPOOL_STAT_ADD(mp, put_bulk, 1);
+ RTE_MEMPOOL_STAT_ADD(mp, put_objs, n);
- /* increment stat now, adding in mempool always success */
- RTE_MEMPOOL_CACHE_STAT_ADD(cache, put_bulk, 1);
- RTE_MEMPOOL_CACHE_STAT_ADD(cache, put_objs, n);
+ goto driver_enqueue;
+ }
- /* The request itself is too big for the cache */
- if (unlikely(n > cache->flushthresh))
- goto driver_enqueue_stats_incremented;
+ /* Prepare to add the objects to the cache. */
+ cache_objs = __rte_mempool_cache_zc_put_bulk(cache, mp, n);
- /*
- * The cache follows the following algorithm:
- * 1. If the objects cannot be added to the cache without crossing
- * the flush threshold, flush the cache to the backend.
- * 2. Add the objects to the cache.
- */
+ /* The request itself is too big for the cache? */
+ if (unlikely(cache_objs == NULL)) {
+ /* Increment stats now, adding in mempool always succeeds. */
+ RTE_MEMPOOL_CACHE_STAT_ADD(cache, put_bulk, 1);
+ RTE_MEMPOOL_CACHE_STAT_ADD(cache, put_objs, n);
Shouldn't it be RTE_MEMPOOL_STAT_ADD() here?
- if (cache->len + n <= cache->flushthresh) {
- cache_objs = &cache->objs[cache->len];
- cache->len += n;
- } else {
- cache_objs = &cache->objs[0];
- rte_mempool_ops_enqueue_bulk(mp, cache_objs, cache->len);
- cache->len = n;
+ goto driver_enqueue;
}
/* Add the objects to the cache. */
@@ -1399,13 +1584,7 @@ rte_mempool_do_generic_put(struct rte_mempool *mp, void
* const *obj_table,
driver_enqueue:
- /* increment stat now, adding in mempool always success */
- RTE_MEMPOOL_STAT_ADD(mp, put_bulk, 1);
- RTE_MEMPOOL_STAT_ADD(mp, put_objs, n);
-
-driver_enqueue_stats_incremented:
-
- /* push objects to the backend */
+ /* Push the objects to the backend. */
rte_mempool_ops_enqueue_bulk(mp, obj_table, n);
}
diff --git a/lib/mempool/rte_mempool_trace_fp.h b/lib/mempool/rte_mempool_trace_fp.h
index ed060e887c..14666457f7 100644
--- a/lib/mempool/rte_mempool_trace_fp.h
+++ b/lib/mempool/rte_mempool_trace_fp.h
@@ -109,6 +109,29 @@ RTE_TRACE_POINT_FP(
rte_trace_point_emit_ptr(mempool);
)
+RTE_TRACE_POINT_FP(
+ rte_mempool_trace_cache_zc_put_bulk,
+ RTE_TRACE_POINT_ARGS(void *cache, void *mempool, uint32_t nb_objs),
+ rte_trace_point_emit_ptr(cache);
+ rte_trace_point_emit_ptr(mempool);
+ rte_trace_point_emit_u32(nb_objs);
+)
+
+RTE_TRACE_POINT_FP(
+ rte_mempool_trace_cache_zc_put_rewind,
+ RTE_TRACE_POINT_ARGS(void *cache, uint32_t nb_objs),
+ rte_trace_point_emit_ptr(cache);
+ rte_trace_point_emit_u32(nb_objs);
+)
+
+RTE_TRACE_POINT_FP(
+ rte_mempool_trace_cache_zc_get_bulk,
+ RTE_TRACE_POINT_ARGS(void *cache, void *mempool, uint32_t nb_objs),
+ rte_trace_point_emit_ptr(cache);
+ rte_trace_point_emit_ptr(mempool);
+ rte_trace_point_emit_u32(nb_objs);
+)
+
#ifdef __cplusplus
}
#endif
diff --git a/lib/mempool/version.map b/lib/mempool/version.map
index b67d7aace7..1383ae6db2 100644
--- a/lib/mempool/version.map
+++ b/lib/mempool/version.map
@@ -63,6 +63,11 @@ EXPERIMENTAL {
__rte_mempool_trace_ops_alloc;
__rte_mempool_trace_ops_free;
__rte_mempool_trace_set_ops_byname;
+
+ # added in 23.03
+ __rte_mempool_trace_cache_zc_put_bulk;
+ __rte_mempool_trace_cache_zc_put_rewind;
+ __rte_mempool_trace_cache_zc_get_bulk;
};
INTERNAL {
