From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3CA26C88E4D for ; Fri, 11 Sep 2026 22:58:56 +0000 (UTC) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 329664027A; Sat, 12 Sep 2026 00:58:55 +0200 (CEST) Received: from mail-pg1-f175.google.com (mail-pg1-f175.google.com [209.85.215.175]) by mails.dpdk.org (Postfix) with ESMTP id C965B40275 for ; Sat, 12 Sep 2026 00:58:53 +0200 (CEST) Received: by mail-pg1-f175.google.com with SMTP id 41be03b00d2f7-cc4d03f95dfso763219a12.2 for ; Fri, 11 Sep 2026 15:58:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=networkplumber-org.20251104.gappssmtp.com; s=20251104; t=1789167533; x=1789772333; darn=dpdk.org; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to:content-type; bh=enqAzNYEFf/5V5MaRW332cKsnSp02HNDlCKyoq8iw10=; b=dZ/devtsAoUMK+lKOv/paWFNn1FL6rFs4XQJmoTKPo6h/YQQfqG04pDH/RW4MXpDLH GSxMuUQjPUTX3It6KfFcEQsE+CiGiC3LASDb6aDJUxkNsZITIN9JTAOoLIx1V13YGpgy 3sG7up7tQMP5MuAI6369eRYGRjh+Nk5p7weis1JZ88VlryWOYuF4RZWij2/b5sQ1jOUK 0dbKT67AWzdU9RURwJJR5n1NNTO01BqZL4jq+tM3v/lW5OzzVcOANLV/1C8CxhWSJcnT aAIsLyKlnxkFQooNzMW/DS7vx1Vk8iSbe8tUME+3wQcMSD0rGpHtTmLz9S03raC0Emtc FsbQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1789167533; x=1789772333; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-gg:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to:content-type; bh=enqAzNYEFf/5V5MaRW332cKsnSp02HNDlCKyoq8iw10=; b=qBL0dzsIV1SL+Ovrtp1SmfWuWWZQaUhwsieGeNlqQcMej9oLONJ7nwgTjdXh8DX6Yy FVg1vfx6R7m3KHPuAChCj91K1CRZrqf6miD6kOq4+AZpVDgqWrWhjvsFlwkm0TFBDxkh JPZkIE2OZmGpwn/y7YVL2sHegc7/gtrSntfg1w61A4RLcXv5qUyWgo0qub5a2uoE2kFM Kp2yKpr6jEYEh1R9R6OAq9CmZXhmJ3RFWn1XS0WRgqBJ5+RaHnCfjqkqp4LCw3LiivMU JcTUMJQ+Iz/zt8fm0nImVSaoZRP75g2/o0q0J8PNyJgiJN4sfrsCfCQr7JVb3vvLQrAW 9x8g== X-Gm-Message-State: AFuF++m+OV6dwjh6XZLcaW6H3kClHvPB6DkzXWS1nKSz2l8AaLr1XL7q TY/dCfOFHbAyA5hYxp2Tek9+kdt3caGFpU6zdT5kGN1/dgLat0zxA6F2oVeKAMSN8dOvFmEfwlY 9Dbn3 X-Gm-Gg: AYBFou2aTZNO9F9dYEkLROyS6ZXdGXridH6f1L956wqhECcZMtX8DuIRFKGRyRVnqCX xlPq+2YaIUFyBRITUEyThf8+Azs1dV7Dp8rGEb6eUr0KYyZVZnJwLQeMdBQuRGjTALecVd5Gwtl 8IhOXH0suekPRcRpK/G74S/EUU0twZP6bIaY19RQFCeZkSGMBsjNTxcFTkJCaYGOGDsSmZZPYpN 998vrftZ3PriTEIFJbOgNsBgQRFenMmfQEEsvmDMnABTJXhEhbJBHuwi8KixxKsfvSO1d28e54s mW/nMyclk/+ytjdS1ek8DQWPqULbDoPrkCgUM3LHMl2meUXMS89HV/O+JtP7i1WcNy8AdnpZgWz EtDaIh676Cxxg1fNEoVdYv3plvpxPOq163kGwNqEeTFQ2XHGl9UieoPsgkqjIkbg2vUdhWt7/nF HrUsWR1rzKfLisKwdgGmeu+82C5kFftSv2X1zHovwOkvqEgC6jq9oc6QOv7W1bNvqfBMoZuY2Kc 0HP0zcpkxMhzsJgVQDL0XCaESQ9mUCkq/+Kyw== X-Received: by 2002:a17:90b:3e50:b0:38e:9ef9:eb97 with SMTP id 98e67ed59e1d1-39d9c1d8f30mr11863473a91.16.1789167532568; Fri, 11 Sep 2026 15:58:52 -0700 (PDT) Received: from phoenix.lan (204-195-96-226.wavecable.com. [204.195.96.226]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-39d95713602sm7032434a91.11.2026.09.11.15.58.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 11 Sep 2026 15:58:52 -0700 (PDT) From: Stephen Hemminger To: dev@dpdk.org Cc: Stephen Hemminger , =?UTF-8?q?Mattias=20R=C3=B6nnblom?= Subject: [RFC] eal: allow setting random number generator seed Date: Fri, 11 Sep 2026 15:58:45 -0700 Message-ID: <20260911225845.3168061-1-stephen@networkplumber.org> X-Mailer: git-send-email 2.53.0 MIME-Version: 1.0 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 Many performance tests use rte_rand() and the random number can perturb the results. Add an ability to overide the automatic random seed on DPDK startup. This is not a security problem since rte_rand() is documented as not being cryptographically secure. Signed-off-by: Stephen Hemminger --- lib/eal/common/rte_random.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) diff --git a/lib/eal/common/rte_random.c b/lib/eal/common/rte_random.c index 576a32a46c..cdad60049b 100644 --- a/lib/eal/common/rte_random.c +++ b/lib/eal/common/rte_random.c @@ -247,7 +247,18 @@ eal_rand_init(void) RTE_LCORE_VAR_ALLOC(rand_state); - seed = __rte_random_initial_seed(); + const char *env = getenv("DPDK_RANDOM_SEED"); + if (env != NULL && *env != '\0') { + char *end; + + errno = 0; + seed = strtoull(env, &end, 0); + if (errno != 0 || *end != '\0') + rte_exit(EXIT_FAILURE, + "invalid DPDK_RANDOM_SEED: %s\n", env); + } else { + seed = __rte_random_initial_seed(); + } rte_srand(seed); } -- 2.53.0