From patchwork Tue Nov 29 00:03:55 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 13058020 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 23110C4321E for ; Tue, 29 Nov 2022 00:04:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234812AbiK2AE2 (ORCPT ); Mon, 28 Nov 2022 19:04:28 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39454 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234760AbiK2AE0 (ORCPT ); Mon, 28 Nov 2022 19:04:26 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [IPv6:2604:1380:4641:c500::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 493801AD92 for ; Mon, 28 Nov 2022 16:04:26 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id D954B61516 for ; Tue, 29 Nov 2022 00:04:25 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D7244C43141; Tue, 29 Nov 2022 00:04:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1669680265; bh=Y43qJ/bNGK9Ddo25ogKXBarnhJnlJyovlWA7DkFzBLE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=Q7TjS4Ihh0OtWz32ArdI3FbEP9c/5tx+0f1FrR3O/fm0U/F9maIjVrCg4XZzrjADc g9QrOJdtQj58hg3lH6RpChyJpmZ06qWKwBu56daQbuweWGvMn2CrEXp29i3L8AAE5B fMycNHEDbCEihMhICWVYjvi2hBnW14hc8P/J5DTU3RIzGvl1XEYzhzRkTLP4wLwvXc j/J6vSkm+mWFgMK5pLd2LqXOKQa/4z8/pScnAgSFRRvtW8hhVoesCK+kjOulPEX/Ul sniDrlqKMrKk3joAmmwIKpV8eiX+5GRCbuuDbXYJbZ6xGN8jzxrIK1Wrtr/06fTssa EhLuZ0BmCYtpw== From: Mark Brown To: Catalin Marinas , Will Deacon , Shuah Khan Cc: linux-arm-kernel@lists.infradead.org, linux-kselftest@vger.kernel.org, Mark Brown Subject: [PATCH v1 3/3] kselftest/arm64: Allow epoll_wait() to return more than one result Date: Tue, 29 Nov 2022 00:03:55 +0000 Message-Id: <20221129000355.812425-4-broonie@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20221129000355.812425-1-broonie@kernel.org> References: <20221129000355.812425-1-broonie@kernel.org> MIME-Version: 1.0 X-Developer-Signature: v=1; a=openpgp-sha256; l=3344; i=broonie@kernel.org; h=from:subject; bh=Y43qJ/bNGK9Ddo25ogKXBarnhJnlJyovlWA7DkFzBLE=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBjhUxqhIIw+/0qMtilo7qwuKBAbrQGk/zdnqtiunQb UH+OizmJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCY4VMagAKCRAk1otyXVSH0BUgB/ 9/acYMk3PSV+yuqpG5TG1+9R2clCgHlt/XdScreju0VnajaqncYZjjCgK09lMvWJU2URpIOeQaYAEz K0ALu8kKxKdvxKzBNndRWyVZAi+GhWvl31EhlmQkCuRj56vFVGy4/g6Gu59CeYcLO4wp5f9wxL5iE0 qEWi6hRN+Q1TwBJM6g0YsfQ6qKeeyocB8QhD0VK1FPk2H4pYsUl/sk+m+SRndEMNbC21ygg1hLcjZD 046yZfje1ZnDHyU9wWb8d/DllyFqnGPUIiRVH2awAW6Ym434ptFzCSBppNszx1ZjypUjbKrphx4MPR V6KKjEPUvr8yFJ8yGu2vDJISdMKwKd X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org When everything is starting up we are likely to have a lot of child processes producing output at once. This means that we can reduce overhead a bit by allowing epoll_wait() to return more than one descriptor at once, it cuts down on the number of system calls we need to do which on virtual platforms where the syscall overhead is a bit more noticable and we're likely to have a lot more children active can make a small but noticable difference. On physical platforms the relatively small number of processes being run and vastly improved speeds push the effects of this change into the noise. Signed-off-by: Mark Brown --- tools/testing/selftests/arm64/fp/fp-stress.c | 27 +++++++++++++------- 1 file changed, 18 insertions(+), 9 deletions(-) diff --git a/tools/testing/selftests/arm64/fp/fp-stress.c b/tools/testing/selftests/arm64/fp/fp-stress.c index 65262cf30b09..d22f6e356440 100644 --- a/tools/testing/selftests/arm64/fp/fp-stress.c +++ b/tools/testing/selftests/arm64/fp/fp-stress.c @@ -39,6 +39,8 @@ struct child_data { static int epoll_fd; static struct child_data *children; +static struct epoll_event *evs; +static int tests; static int num_children; static bool terminate; @@ -393,11 +395,11 @@ static void probe_vls(int vls[], int *vl_count, int set_vl) /* Handle any pending output without blocking */ static void drain_output(bool flush) { - struct epoll_event ev; int ret = 1; + int i; while (ret > 0) { - ret = epoll_wait(epoll_fd, &ev, 1, 0); + ret = epoll_wait(epoll_fd, evs, tests, 0); if (ret < 0) { if (errno == EINTR) continue; @@ -405,8 +407,8 @@ static void drain_output(bool flush) strerror(errno), errno); } - if (ret == 1) - child_output(ev.data.ptr, ev.events, flush); + for (i = 0; i < ret; i++) + child_output(evs[i].data.ptr, evs[i].events, flush); } } @@ -419,10 +421,9 @@ int main(int argc, char **argv) { int ret; int timeout = 10; - int cpus, tests, i, j, c; + int cpus, i, j, c; int sve_vl_count, sme_vl_count, fpsimd_per_cpu; int sve_vls[MAX_VLS], sme_vls[MAX_VLS]; - struct epoll_event ev; struct sigaction sa; while ((c = getopt_long(argc, argv, "t:", options, NULL)) != -1) { @@ -508,6 +509,11 @@ int main(int argc, char **argv) ksft_print_msg("Failed to install SIGCHLD handler: %s (%d)\n", strerror(errno), errno); + evs = calloc(tests, sizeof(*evs)); + if (!evs) + ksft_exit_fail_msg("Failed to allocated %d epoll events\n", + tests); + for (i = 0; i < cpus; i++) { for (j = 0; j < fpsimd_per_cpu; j++) start_fpsimd(&children[num_children++], i, j); @@ -541,7 +547,7 @@ int main(int argc, char **argv) * useful in emulation where we will both be slow and * likely to have a large set of VLs. */ - ret = epoll_wait(epoll_fd, &ev, 1, 1000); + ret = epoll_wait(epoll_fd, evs, tests, 1000); if (ret < 0) { if (errno == EINTR) continue; @@ -550,8 +556,11 @@ int main(int argc, char **argv) } /* Output? */ - if (ret == 1) { - child_output(ev.data.ptr, ev.events, false); + if (ret > 0) { + for (i = 0; i < ret; i++) { + child_output(evs[i].data.ptr, evs[i].events, + false); + } continue; }