From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by dpdk.space (Postfix) with ESMTP id E6F9DA0679 for ; Fri, 5 Apr 2019 15:46:10 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 59EAE1B500; Fri, 5 Apr 2019 15:45:56 +0200 (CEST) Received: from sessmg22.ericsson.net (sessmg22.ericsson.net [193.180.251.58]) by dpdk.org (Postfix) with ESMTP id 7FA851B4FD for ; Fri, 5 Apr 2019 15:45:54 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; d=ericsson.com; s=mailgw201801; c=relaxed/relaxed; q=dns/txt; i=@ericsson.com; t=1554471954; x=1557063954; h=From:Sender:Reply-To:Subject:Date:Message-ID:To:CC:MIME-Version:Content-Type: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=T5oulVZy1wVJZj6v5AUwpLBKqwyu0qA2vY/gs97x9nU=; b=FvTGvzjqDasBdNHwvZwLDk6lViO3SdBUpwGL/xaZO/l1YJpYvSNwjzwbvRG1+peJ F+D/ULzqsTvDT/0Hb0rdwQkefxIm4AFVKb0Gk0YXl1ywHfAyla3qCRwG9KULKTel GSI8/q+XGT3PLwL2KeWf7zAhrlApHxQ2/B8gt6SwTvI=; X-AuditID: c1b4fb3a-851ff70000005461-1f-5ca75c12eb0a Received: from ESESSMB504.ericsson.se (Unknown_Domain [153.88.183.122]) by sessmg22.ericsson.net (Symantec Mail Security) with SMTP id 96.F6.21601.21C57AC5; Fri, 5 Apr 2019 15:45:54 +0200 (CEST) Received: from ESESSMB501.ericsson.se (153.88.183.162) by ESESSMB504.ericsson.se (153.88.183.122) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.1713.5; Fri, 5 Apr 2019 15:45:53 +0200 Received: from selio1a020.lmera.ericsson.se (153.88.183.153) by smtp.internal.ericsson.com (153.88.183.189) with Microsoft SMTP Server id 15.1.1713.5 via Frontend Transport; Fri, 5 Apr 2019 15:45:53 +0200 Received: from breslau.lmera.ericsson.se (breslau.lmera.ericsson.se [150.132.109.241]) by selio1a020.lmera.ericsson.se (8.15.1+Sun/8.15.1) with ESMTP id x35DjrSn014512; Fri, 5 Apr 2019 15:45:54 +0200 (CEST) From: =?UTF-8?q?Mattias=20R=C3=B6nnblom?= To: CC: =?UTF-8?q?Mattias=20R=C3=B6nnblom?= Date: Fri, 5 Apr 2019 15:45:42 +0200 Message-ID: <20190405134542.28618-1-mattias.ronnblom@ericsson.com> X-Mailer: git-send-email 2.17.1 MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrNLMWRmVeSWpSXmKPExsUyM2J7la5QzPIYg4P3eSzefdrO5MDo8WvB UtYAxigum5TUnMyy1CJ9uwSujD2H5QsmWlY8+LiDsYHxqn4XIyeHhICJxMSVPWwgtpDAUUaJ uTdSuxi5gOyvjBLrd21hg3AuMEqcPbuUBcK5xCjR8X4BWAubgKfE5HfdLCC2iICQxNKPl9lB bGYBd4n3j5YzgdjCAtoSbw/3sYLYLAIqEr/nbQCL8wo4Sbx+e5cF4gx5idUbDjBDxAUlTs58 wgIxR1OidftvqJnyEs1bZzNDnKolcX/JF+YJjAKzkLTMQtIyC0nLAkbmVYyixanFxbnpRkZ6 qUWZycXF+Xl6eaklmxiBQXhwy2+rHYwHnzseYhTgYFTi4b1tsTxGiDWxrLgy9xCjBAezkgiv 3MplMUK8KYmVValF+fFFpTmpxYcYpTlYlMR5/wgJxggJpCeWpGanphakFsFkmTg4pRoYOwN+ /f510P7zQSnDm2qfOkWX6LMkOadLHne1/3Xh8dUV7SIL7ad/Xr/PZYG6slmsmO/Pb+tZbp9f OTt7n1a5s/OTsCNVDeuVjOKU787W4u75bn357csKFfdjIXWr1pTI3orUnls523mV3++9Ok4n fEwVT07u/poR7/d8FQdXsu+TwztWOGlGK7EUZyQaajEXFScCALtxH84+AgAA Subject: [dpdk-dev] [RFC] eal: make rte_rand() MT safe X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Message-ID: <20190405134542.5Olqyzghl9L-oUAscWB4W5NL2gGRzwprToU04IZXcuo@z> The rte_rand() documentation left it unspecified if the rte_rand() was multi-thread safe or not, and the implementation (based on lrand48()) was not. This commit makes rte_rand() safe to use from any lcore thread by using lrand48_r() and per-lcore random state structs. Besides the obvious improvement in terms of correctness (for concurrent users), this also much improves rte_rand() performance, since the threads no longer shares state. For the single-threaded case, this patch causes ~10% rte_rand() performance degradation. rte_srand() is left multi-thread unsafe, and external synchronization is required to serialize rte_sand() calls from different lcore threads, and a rte_srand() call with rte_rand() calls made by other lcore threads. The assumption is that the random number generators will be seeded once, during startup. Bugzilla ID: 114 Signed-off-by: Mattias Rönnblom --- lib/librte_eal/common/include/rte_random.h | 25 ++++----- lib/librte_eal/common/meson.build | 1 + lib/librte_eal/common/rte_random.c | 65 ++++++++++++++++++++++ lib/librte_eal/freebsd/eal/Makefile | 1 + lib/librte_eal/freebsd/eal/eal.c | 2 - lib/librte_eal/linux/eal/Makefile | 1 + lib/librte_eal/linux/eal/eal.c | 2 - lib/librte_eal/rte_eal_version.map | 2 + 8 files changed, 80 insertions(+), 19 deletions(-) create mode 100644 lib/librte_eal/common/rte_random.c diff --git a/lib/librte_eal/common/include/rte_random.h b/lib/librte_eal/common/include/rte_random.h index b2ca1c209..bca85a672 100644 --- a/lib/librte_eal/common/include/rte_random.h +++ b/lib/librte_eal/common/include/rte_random.h @@ -16,7 +16,6 @@ extern "C" { #endif #include -#include /** * Seed the pseudo-random generator. @@ -25,14 +24,15 @@ extern "C" { * value. It may need to be re-seeded by the user with a real random * value. * + * This function is not multi-thread safe in regards to other + * rte_srand() calls, nor is it in relation to concurrent rte_rand() + * calls. + * * @param seedval * The value of the seed. */ -static inline void -rte_srand(uint64_t seedval) -{ - srand48((long)seedval); -} +void +rte_srand(uint64_t seedval); /** * Get a pseudo-random value. @@ -41,18 +41,13 @@ rte_srand(uint64_t seedval) * congruential algorithm and 48-bit integer arithmetic, called twice * to generate a 64-bit value. * + * If called from lcore threads, this function is thread-safe. + * * @return * A pseudo-random value between 0 and (1<<64)-1. */ -static inline uint64_t -rte_rand(void) -{ - uint64_t val; - val = (uint64_t)lrand48(); - val <<= 32; - val += (uint64_t)lrand48(); - return val; -} +uint64_t +rte_rand(void); #ifdef __cplusplus } diff --git a/lib/librte_eal/common/meson.build b/lib/librte_eal/common/meson.build index 0670e4102..bafd23207 100644 --- a/lib/librte_eal/common/meson.build +++ b/lib/librte_eal/common/meson.build @@ -35,6 +35,7 @@ common_sources = files( 'rte_keepalive.c', 'rte_malloc.c', 'rte_option.c', + 'rte_random.c', 'rte_reciprocal.c', 'rte_service.c' ) diff --git a/lib/librte_eal/common/rte_random.c b/lib/librte_eal/common/rte_random.c new file mode 100644 index 000000000..9d519d03b --- /dev/null +++ b/lib/librte_eal/common/rte_random.c @@ -0,0 +1,65 @@ +/* SPDX-License-Identifier: BSD-3-Clause + * Copyright(c) 2010-2014 Intel Corporation + * Copyright(c) 2019 Ericsson AB + */ + +#include + +#include +#include +#include +#include + +struct rte_rand_data +{ + struct drand48_data data; +} __rte_cache_aligned; + +static struct rte_rand_data rand_data[RTE_MAX_LCORE]; + +void +rte_srand(uint64_t seedval) +{ + unsigned i; + + /* give the different lcores a different seed, to avoid a + situation where they generate the same sequence */ + for (i = 0; i < RTE_MAX_LCORE; i++) + srand48_r((long)seedval + i, &rand_data[i].data); +} + +static inline uint32_t +__rte_rand48(struct drand48_data *data) +{ + long res; + + lrand48_r(data, &res); + + return (uint32_t)res; +} + +uint64_t +rte_rand(void) +{ + unsigned lcore_id; + struct drand48_data *data; + uint64_t val; + + lcore_id = rte_lcore_id(); + + if (unlikely(lcore_id == LCORE_ID_ANY)) + lcore_id = rte_get_master_lcore(); + + data = &rand_data[lcore_id].data; + + val = __rte_rand48(data); + val <<= 32; + val += __rte_rand48(data); + + return val; +} + +RTE_INIT(rte_rand_init) +{ + rte_srand(rte_get_timer_cycles()); +} diff --git a/lib/librte_eal/freebsd/eal/Makefile b/lib/librte_eal/freebsd/eal/Makefile index 19854ee2c..ca616c480 100644 --- a/lib/librte_eal/freebsd/eal/Makefile +++ b/lib/librte_eal/freebsd/eal/Makefile @@ -69,6 +69,7 @@ SRCS-$(CONFIG_RTE_EXEC_ENV_FREEBSD) += malloc_mp.c SRCS-$(CONFIG_RTE_EXEC_ENV_FREEBSD) += rte_keepalive.c SRCS-$(CONFIG_RTE_EXEC_ENV_FREEBSD) += rte_option.c SRCS-$(CONFIG_RTE_EXEC_ENV_FREEBSD) += rte_service.c +SRCS-$(CONFIG_RTE_EXEC_ENV_FREEBSD) += rte_random.c SRCS-$(CONFIG_RTE_EXEC_ENV_FREEBSD) += rte_reciprocal.c # from arch dir diff --git a/lib/librte_eal/freebsd/eal/eal.c b/lib/librte_eal/freebsd/eal/eal.c index c6ac9028f..5d43310b3 100644 --- a/lib/librte_eal/freebsd/eal/eal.c +++ b/lib/librte_eal/freebsd/eal/eal.c @@ -727,8 +727,6 @@ rte_eal_init(int argc, char **argv) #endif } - rte_srand(rte_rdtsc()); - /* in secondary processes, memory init may allocate additional fbarrays * not present in primary processes, so to avoid any potential issues, * initialize memzones first. diff --git a/lib/librte_eal/linux/eal/Makefile b/lib/librte_eal/linux/eal/Makefile index 6e5261152..729795a10 100644 --- a/lib/librte_eal/linux/eal/Makefile +++ b/lib/librte_eal/linux/eal/Makefile @@ -77,6 +77,7 @@ SRCS-$(CONFIG_RTE_EXEC_ENV_LINUX) += malloc_mp.c SRCS-$(CONFIG_RTE_EXEC_ENV_LINUX) += rte_keepalive.c SRCS-$(CONFIG_RTE_EXEC_ENV_LINUX) += rte_option.c SRCS-$(CONFIG_RTE_EXEC_ENV_LINUX) += rte_service.c +SRCS-$(CONFIG_RTE_EXEC_ENV_LINUX) += rte_random.c SRCS-$(CONFIG_RTE_EXEC_ENV_LINUX) += rte_reciprocal.c # from arch dir diff --git a/lib/librte_eal/linux/eal/eal.c b/lib/librte_eal/linux/eal/eal.c index f7ae62d7b..c2bdf0a67 100644 --- a/lib/librte_eal/linux/eal/eal.c +++ b/lib/librte_eal/linux/eal/eal.c @@ -1083,8 +1083,6 @@ rte_eal_init(int argc, char **argv) #endif } - rte_srand(rte_rdtsc()); - if (rte_eal_log_init(logid, internal_config.syslog_facility) < 0) { rte_eal_init_alert("Cannot init logging."); rte_errno = ENOMEM; diff --git a/lib/librte_eal/rte_eal_version.map b/lib/librte_eal/rte_eal_version.map index d6e375135..0d60668fa 100644 --- a/lib/librte_eal/rte_eal_version.map +++ b/lib/librte_eal/rte_eal_version.map @@ -366,10 +366,12 @@ EXPERIMENTAL { rte_mp_request_async; rte_mp_sendmsg; rte_option_register; + rte_rand; rte_realloc_socket; rte_service_lcore_attr_get; rte_service_lcore_attr_reset_all; rte_service_may_be_active; rte_socket_count; rte_socket_id_by_idx; + rte_srand; }; -- 2.17.1