From mboxrd@z Thu Jan 1 00:00:00 1970 From: Robert Sanford Subject: [PATCH 3/4] port: fix full burst checks in f_tx_bulk ops Date: Mon, 28 Mar 2016 16:51:36 -0400 Message-ID: <1459198297-49854-4-git-send-email-rsanford@akamai.com> References: <1459198297-49854-1-git-send-email-rsanford@akamai.com> To: dev@dpdk.org, cristian.dumitrescu@intel.com Return-path: Received: from mail-vk0-f66.google.com (mail-vk0-f66.google.com [209.85.213.66]) by dpdk.org (Postfix) with ESMTP id 02231475E for ; Mon, 28 Mar 2016 22:52:17 +0200 (CEST) Received: by mail-vk0-f66.google.com with SMTP id e6so16778493vkh.1 for ; Mon, 28 Mar 2016 13:52:17 -0700 (PDT) In-Reply-To: <1459198297-49854-1-git-send-email-rsanford@akamai.com> List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" For several f_tx_bulk functions in rte_port_{ethdev,ring,sched}.c, it appears that the intent of the bsz_mask logic is to test whether pkts_mask contains a full burst (i.e., the least significant bits are set). There are two problems with the bsz_mask code: 1) It truncates by using the wrong size for local variable uint32_t bsz_mask, and 2) We may pass oversized bursts to the underlying ethdev/ring/sched, e.g., tx_burst_sz=16, bsz_mask=0x8000, and pkts_mask=0x1ffff (17 packets), results in expr==0, and we send a burst larger than desired (and non-power-of-2) to the underlying tx burst interface. We propose to effectively set bsz_mask = (1 << tx_burst_sz) - 1 (while avoiding truncation for tx_burst_sz=64), to cache the mask value of a full burst, and then do a simple compare with pkts_mask in each f_tx_bulk. Signed-off-by: Robert Sanford --- lib/librte_port/rte_port_ethdev.c | 15 ++++----------- lib/librte_port/rte_port_ring.c | 16 ++++------------ lib/librte_port/rte_port_sched.c | 7 ++----- 3 files changed, 10 insertions(+), 28 deletions(-) diff --git a/lib/librte_port/rte_port_ethdev.c b/lib/librte_port/rte_port_ethdev.c index 1c34602..3fb4947 100644 --- a/lib/librte_port/rte_port_ethdev.c +++ b/lib/librte_port/rte_port_ethdev.c @@ -188,7 +188,7 @@ rte_port_ethdev_writer_create(void *params, int socket_id) port->queue_id = conf->queue_id; port->tx_burst_sz = conf->tx_burst_sz; port->tx_buf_count = 0; - port->bsz_mask = 1LLU << (conf->tx_burst_sz - 1); + port->bsz_mask = UINT64_MAX >> (64 - conf->tx_burst_sz); return port; } @@ -229,12 +229,9 @@ rte_port_ethdev_writer_tx_bulk(void *port, { struct rte_port_ethdev_writer *p = (struct rte_port_ethdev_writer *) port; - uint32_t bsz_mask = p->bsz_mask; uint32_t tx_buf_count = p->tx_buf_count; - uint64_t expr = (pkts_mask & (pkts_mask + 1)) | - ((pkts_mask & bsz_mask) ^ bsz_mask); - if (expr == 0) { + if (pkts_mask == p->bsz_mask) { uint64_t n_pkts = __builtin_popcountll(pkts_mask); uint32_t n_pkts_ok; @@ -369,7 +366,7 @@ rte_port_ethdev_writer_nodrop_create(void *params, int socket_id) port->queue_id = conf->queue_id; port->tx_burst_sz = conf->tx_burst_sz; port->tx_buf_count = 0; - port->bsz_mask = 1LLU << (conf->tx_burst_sz - 1); + port->bsz_mask = UINT64_MAX >> (64 - conf->tx_burst_sz); /* * When n_retries is 0 it means that we should wait for every packet to @@ -435,13 +432,9 @@ rte_port_ethdev_writer_nodrop_tx_bulk(void *port, { struct rte_port_ethdev_writer_nodrop *p = (struct rte_port_ethdev_writer_nodrop *) port; - - uint32_t bsz_mask = p->bsz_mask; uint32_t tx_buf_count = p->tx_buf_count; - uint64_t expr = (pkts_mask & (pkts_mask + 1)) | - ((pkts_mask & bsz_mask) ^ bsz_mask); - if (expr == 0) { + if (pkts_mask == p->bsz_mask) { uint64_t n_pkts = __builtin_popcountll(pkts_mask); uint32_t n_pkts_ok; diff --git a/lib/librte_port/rte_port_ring.c b/lib/librte_port/rte_port_ring.c index 765ecc5..b36e4ce 100644 --- a/lib/librte_port/rte_port_ring.c +++ b/lib/librte_port/rte_port_ring.c @@ -217,7 +217,7 @@ rte_port_ring_writer_create_internal(void *params, int socket_id, port->ring = conf->ring; port->tx_burst_sz = conf->tx_burst_sz; port->tx_buf_count = 0; - port->bsz_mask = 1LLU << (conf->tx_burst_sz - 1); + port->bsz_mask = UINT64_MAX >> (64 - conf->tx_burst_sz); port->is_multi = is_multi; return port; @@ -299,13 +299,9 @@ rte_port_ring_writer_tx_bulk_internal(void *port, { struct rte_port_ring_writer *p = (struct rte_port_ring_writer *) port; - - uint32_t bsz_mask = p->bsz_mask; uint32_t tx_buf_count = p->tx_buf_count; - uint64_t expr = (pkts_mask & (pkts_mask + 1)) | - ((pkts_mask & bsz_mask) ^ bsz_mask); - if (expr == 0) { + if (pkts_mask == p->bsz_mask) { uint64_t n_pkts = __builtin_popcountll(pkts_mask); uint32_t n_pkts_ok; @@ -486,7 +482,7 @@ rte_port_ring_writer_nodrop_create_internal(void *params, int socket_id, port->ring = conf->ring; port->tx_burst_sz = conf->tx_burst_sz; port->tx_buf_count = 0; - port->bsz_mask = 1LLU << (conf->tx_burst_sz - 1); + port->bsz_mask = UINT64_MAX >> (64 - conf->tx_burst_sz); port->is_multi = is_multi; /* @@ -613,13 +609,9 @@ rte_port_ring_writer_nodrop_tx_bulk_internal(void *port, { struct rte_port_ring_writer_nodrop *p = (struct rte_port_ring_writer_nodrop *) port; - - uint32_t bsz_mask = p->bsz_mask; uint32_t tx_buf_count = p->tx_buf_count; - uint64_t expr = (pkts_mask & (pkts_mask + 1)) | - ((pkts_mask & bsz_mask) ^ bsz_mask); - if (expr == 0) { + if (pkts_mask == p->bsz_mask) { uint64_t n_pkts = __builtin_popcountll(pkts_mask); uint32_t n_pkts_ok; diff --git a/lib/librte_port/rte_port_sched.c b/lib/librte_port/rte_port_sched.c index c5ff8ab..5b6afc4 100644 --- a/lib/librte_port/rte_port_sched.c +++ b/lib/librte_port/rte_port_sched.c @@ -185,7 +185,7 @@ rte_port_sched_writer_create(void *params, int socket_id) port->sched = conf->sched; port->tx_burst_sz = conf->tx_burst_sz; port->tx_buf_count = 0; - port->bsz_mask = 1LLU << (conf->tx_burst_sz - 1); + port->bsz_mask = UINT64_MAX >> (64 - conf->tx_burst_sz); return port; } @@ -214,12 +214,9 @@ rte_port_sched_writer_tx_bulk(void *port, uint64_t pkts_mask) { struct rte_port_sched_writer *p = (struct rte_port_sched_writer *) port; - uint32_t bsz_mask = p->bsz_mask; uint32_t tx_buf_count = p->tx_buf_count; - uint64_t expr = (pkts_mask & (pkts_mask + 1)) | - ((pkts_mask & bsz_mask) ^ bsz_mask); - if (expr == 0) { + if (pkts_mask == p->bsz_mask) { __rte_unused uint32_t nb_tx; uint64_t n_pkts = __builtin_popcountll(pkts_mask); -- 1.7.1