From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id E412C42457; Sun, 22 Jan 2023 21:34:39 +0100 (CET) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 890E5400EF; Sun, 22 Jan 2023 21:34:39 +0100 (CET) Received: from forward502c.mail.yandex.net (forward502c.mail.yandex.net [178.154.239.210]) by mails.dpdk.org (Postfix) with ESMTP id BD3FB400D4 for ; Sun, 22 Jan 2023 21:34:38 +0100 (CET) Received: from sas1-71299a9d5a62.qloud-c.yandex.net (sas1-71299a9d5a62.qloud-c.yandex.net [IPv6:2a02:6b8:c08:210e:0:640:7129:9a9d]) by forward502c.mail.yandex.net (Yandex) with ESMTP id CE2D35EA92; Sun, 22 Jan 2023 23:34:37 +0300 (MSK) Received: by sas1-71299a9d5a62.qloud-c.yandex.net (smtp/Yandex) with ESMTPSA id XYwbFZwfwuQ1-hX4wzhUs; Sun, 22 Jan 2023 23:34:36 +0300 X-Yandex-Fwd: 1 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=yandex.ru; s=mail; t=1674419677; bh=i38CmzJyfpNm8wUiVe7lSLABuUOrnmpEBIDXFANtk0c=; h=From:In-Reply-To:Cc:Date:References:To:Subject:Message-ID; b=omWo6IXlzFY7dJf5GUwuNUzQQzar3CgP8I5a57bm4MbkQN5sz35ZzMB+DLmo6mn1H 3JOOUB+rTEuX8zHqJn7eQBZxhGrRgPRbecEAOIm9qYBOlQhRNOQXCUGxCXAaM0NxeP rUmqG8N6csrHrNuVcY7t1D+kl2DnUxDbVWVl2d1o= Authentication-Results: sas1-71299a9d5a62.qloud-c.yandex.net; dkim=pass header.i=@yandex.ru Message-ID: <60d35262-51bd-3d74-28f8-c2dda50d3400@yandex.ru> Date: Sun, 22 Jan 2023 20:34:33 +0000 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.4.2 Subject: Re: [PATCH v5] mempool cache: add zero-copy get and put functions Content-Language: en-US To: =?UTF-8?Q?Morten_Br=c3=b8rup?= , olivier.matz@6wind.com, andrew.rybchenko@oktetlabs.ru, honnappa.nagarahalli@arm.com, kamalakshitha.aligeri@arm.com, bruce.richardson@intel.com, konstantin.ananyev@huawei.com, dev@dpdk.org Cc: nd@arm.com References: <98CBD80474FA8B44BF855DF32C47DC35D87488@smartserver.smartshare.dk> <20221227151700.80887-1-mb@smartsharesystems.com> From: Konstantin Ananyev In-Reply-To: <20221227151700.80887-1-mb@smartsharesystems.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org 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 > 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 > --- > 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 > #include > #include > +#include > > #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 {