From patchwork Thu Sep 12 18:13:54 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Reinette Chatre X-Patchwork-Id: 828031 Received: from mgamail.intel.com (mgamail.intel.com [198.175.65.21]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7DD9E1BFDFF; Thu, 12 Sep 2024 18:04:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.175.65.21 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726164298; cv=none; b=Y2GWLgUP64/mT2Fh+B+SMEQBa9Y44InYAZpPyE6aCpYpd4inOCzAtxNCWnckR/jTBFcaGeuZJXPzX3bYZSGS+SLOe2K9QCaZP+VmwTcMZT3ipUjYJ90qGgvr0+jtEO2xYo7PzrAjZElDj9Ye9AaYRgoiFOoJaE20EHEs6CRiGys= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726164298; c=relaxed/simple; bh=uaLNw3+ytN+CB1MwOPqpnul7cEtlDlmWNYdX1kzswVg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=puJc9QlLY0tbQkJy+gwksg0vBjcanSMl1tjulmKPwYxpb1wVMA4fd6GbMtFQ/VlHVVChFCHMn0VmdShs2P1HkwYhZX7GuIwjU2Nw90vueEHZgpaButhxITCRZWMnAbvhCot4iSw+iVdoOWI4eie9y4JHF040cyM7f2MAww4O/7E= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=HRXAAln6; arc=none smtp.client-ip=198.175.65.21 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="HRXAAln6" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1726164297; x=1757700297; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=uaLNw3+ytN+CB1MwOPqpnul7cEtlDlmWNYdX1kzswVg=; b=HRXAAln6r0MFEcuL20b0pEkaO8TENzRyWNOXbqupAM+Hbbgb3z0FeaHg /LjDU0Q8GVrNJ9GbBPx4BzK8zaSj0FkIejpOLT0yGYMEoDKq55hX9Qrfo gCvlMlCJKVsMtoELDox5AGUSJ/RSuLN6Ne5fJ2PgmkP4uWxcM+EO4mYx3 jXFsXoyNRw42gwZ+hrDxkz72HC12/aVWzGLUkzgMeVZtKhksXMAXhIZf/ CfFtufsUXQMhNUboR/SSQtsjHj4JWnYB1LHQOo5KiBGBmAPt65CdK3jRR NMk6Y7j5lsE8moLEXEWOl6V+vD4UAdmL7dwzvaCPr56/JFYLUR91RGEjS w==; X-CSE-ConnectionGUID: i9YA/Y32Tj+BtA/h98CvgQ== X-CSE-MsgGUID: qtb7WJ18SJCA/v7VvMMJWg== X-IronPort-AV: E=McAfee;i="6700,10204,11193"; a="24976593" X-IronPort-AV: E=Sophos;i="6.10,223,1719903600"; d="scan'208";a="24976593" Received: from orviesa009.jf.intel.com ([10.64.159.149]) by orvoesa113.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Sep 2024 11:04:53 -0700 X-CSE-ConnectionGUID: fMHFH9m7QLaVIK7X+n8i4w== X-CSE-MsgGUID: GBeizUvsTCChkp/pmCUMVA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.10,223,1719903600"; d="scan'208";a="67724612" Received: from b04f130c85c0.jf.intel.com (HELO rchatre-desk1.jf.intel.com) ([10.165.154.99]) by orviesa009-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Sep 2024 11:04:52 -0700 From: Reinette Chatre To: fenghua.yu@intel.com, shuah@kernel.org, tony.luck@intel.com, peternewman@google.com, babu.moger@amd.com, ilpo.jarvinen@linux.intel.com Cc: maciej.wieczor-retman@intel.com, reinette.chatre@intel.com, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH V2 05/13] selftests/resctrl: Make wraparound handling obvious Date: Thu, 12 Sep 2024 11:13:54 -0700 Message-ID: X-Mailer: git-send-email 2.46.0 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Within mba_setup() the programmed bandwidth delay value starts at the maximum (100, or rather ALLOCATION_MAX) and progresses towards ALLOCATION_MIN by decrementing with ALLOCATION_STEP. The programmed bandwidth delay should never be negative, so representing it with an unsigned int is most appropriate. This may introduce confusion because of the "allocation > ALLOCATION_MAX" check used to check wraparound of the subtraction. Modify the mba_setup() flow to start at the minimum, ALLOCATION_MIN, and incrementally, with ALLOCATION_STEP steps, adjust the bandwidth delay value. This avoids wraparound while making the purpose of "allocation > ALLOCATION_MAX" clear and eliminates the need for the "allocation < ALLOCATION_MIN" check. Reported-by: Ilpo Järvinen Closes: https://lore.kernel.org/lkml/1903ac13-5c9c-ef8d-78e0-417ac34a971b@linux.intel.com/ Signed-off-by: Reinette Chatre Reviewed-by: Ilpo Järvinen --- Changes since V1: - New patch - Add Ilpo's Reviewed-by tag. --- tools/testing/selftests/resctrl/mba_test.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/tools/testing/selftests/resctrl/mba_test.c b/tools/testing/selftests/resctrl/mba_test.c index ab8496a4925b..da40a8ed4413 100644 --- a/tools/testing/selftests/resctrl/mba_test.c +++ b/tools/testing/selftests/resctrl/mba_test.c @@ -39,7 +39,8 @@ static int mba_setup(const struct resctrl_test *test, const struct user_params *uparams, struct resctrl_val_param *p) { - static int runs_per_allocation, allocation = 100; + static unsigned int allocation = ALLOCATION_MIN; + static int runs_per_allocation; char allocation_str[64]; int ret; @@ -50,7 +51,7 @@ static int mba_setup(const struct resctrl_test *test, if (runs_per_allocation++ != 0) return 0; - if (allocation < ALLOCATION_MIN || allocation > ALLOCATION_MAX) + if (allocation > ALLOCATION_MAX) return END_OF_TESTS; sprintf(allocation_str, "%d", allocation); @@ -59,7 +60,7 @@ static int mba_setup(const struct resctrl_test *test, if (ret < 0) return ret; - allocation -= ALLOCATION_STEP; + allocation += ALLOCATION_STEP; return 0; } @@ -72,8 +73,9 @@ static int mba_measure(const struct user_params *uparams, static bool show_mba_info(unsigned long *bw_imc, unsigned long *bw_resc) { - int allocation, runs; + unsigned int allocation; bool ret = false; + int runs; ksft_print_msg("Results are displayed in (MB)\n"); /* Memory bandwidth from 100% down to 10% */ @@ -103,7 +105,7 @@ static bool show_mba_info(unsigned long *bw_imc, unsigned long *bw_resc) avg_diff_per > MAX_DIFF_PERCENT ? "Fail:" : "Pass:", MAX_DIFF_PERCENT, - ALLOCATION_MAX - ALLOCATION_STEP * allocation); + ALLOCATION_MIN + ALLOCATION_STEP * allocation); ksft_print_msg("avg_diff_per: %d%%\n", avg_diff_per); ksft_print_msg("avg_bw_imc: %lu\n", avg_bw_imc);