From patchwork Thu Sep 12 18:14:00 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Reinette Chatre X-Patchwork-Id: 13802413 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 7C2671C1AC8; Thu, 12 Sep 2024 18:05:00 +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=1726164302; cv=none; b=kEROgHM8Woc6bsi8ce3TxaMgNj1gTQ6KJQ9MAkghmRmEnZsDLXl2WoatiW6rpqE139rgKDh73tP4PQIXyYb/fg4sgmA+c+KR7lWRoRJ2jHClC3/+Vr8F7H0i/E4CkEdrpiAWeD58tI1qs0v99gc1lY768t97WrOZKcXesOgQ4N4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726164302; c=relaxed/simple; bh=50bfxJYl40uFsNDlPpwTgHHyGEMj7MLBfEaCUOJS8x8=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=p1DETCb2knsmHDLDeKQnap3cHiKJBX/StVykSkQ6acFg9XfDweKCYUfe37D/XtB2yqptTUZoi7jPjpt+pBevpAJ3EoPhqz17sZ0DaMDMAkuO0wqy90o4X7fgO33iMtzXieyiGpJw7H8D8OsBBPNZIssZqNuzs6z2bftfjThDxNc= 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=JF3I60B4; 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="JF3I60B4" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1726164301; x=1757700301; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=50bfxJYl40uFsNDlPpwTgHHyGEMj7MLBfEaCUOJS8x8=; b=JF3I60B4mJDhYv03SiF/hffX5qB8MpfNPjSSx3JdY1VlD2GU1DWjRrUH Odm6mOYUxviH93sfpags5ik+IOk1sk/SUVH8URi0UrnqNTJOfOLt5Iwf2 2QG1e3ZYC5avxnjO63RP6kpLr7cRDYoAfE10YwUkbJVmlMpxW/8Jh8EbD TvoOzqNOr5Pf4O1Z33skrxrKoY2lFL6NXQOjjueIznqq7NRmUa0770ulj vqpbowGsYpHMhUm+sUH5VTtBLoIV3C5+j7rGPTrAoPZ0NU6V/dg+m5AWy yPw17l913triD7UnlxtVq915RIPRPG13tl+p1fGOWiFGNfWsgFd+JRC55 A==; X-CSE-ConnectionGUID: Dp7fKhhtR1qjSMr/bNulew== X-CSE-MsgGUID: WiE7Vsf8R7m2hwS0BynK4Q== X-IronPort-AV: E=McAfee;i="6700,10204,11193"; a="24976618" X-IronPort-AV: E=Sophos;i="6.10,223,1719903600"; d="scan'208";a="24976618" 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: M99khh2KSlGihpGhdGDRWQ== X-CSE-MsgGUID: 9EP+TjQKRbesQjLTd/GAiA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.10,223,1719903600"; d="scan'208";a="67724631" 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 11:04:53 -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 11/13] selftests/resctrl: Use cache size to determine "fill_buf" buffer size Date: Thu, 12 Sep 2024 11:14:00 -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 By default the MBM and MBA tests use the "fill_buf" benchmark to read from a buffer with the goal to measure the memory bandwidth generated by this buffer access. Care should be taken when sizing the buffer used by the "fill_buf" benchmark. If the buffer is small enough to fit in the cache then it cannot be expected that the benchmark will generate much memory bandwidth. For example, on a system with 320MB L3 cache the existing hardcoded default of 250MB is insufficient. Use the measured cache size to determine a buffer size that can be expected to trigger memory access while keeping the existing default as minimum that has been appropriate for testing so far. Signed-off-by: Reinette Chatre Reviewed-by: Ilpo Järvinen --- Changes since V1: - Ensure buffer is at least double L3 cache size. (Ilpo) - Support user override of default buffer size. (Ilpo) --- tools/testing/selftests/resctrl/mba_test.c | 8 +++++++- tools/testing/selftests/resctrl/mbm_test.c | 8 +++++++- 2 files changed, 14 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/resctrl/mba_test.c b/tools/testing/selftests/resctrl/mba_test.c index 7e43056c8737..d8d9637c1951 100644 --- a/tools/testing/selftests/resctrl/mba_test.c +++ b/tools/testing/selftests/resctrl/mba_test.c @@ -182,7 +182,13 @@ static int mba_run_test(const struct resctrl_test *test, const struct user_param fill_buf.memflush = uparams->fill_buf->memflush; param.fill_buf = &fill_buf; } else if (!uparams->benchmark_cmd[0]) { - fill_buf.buf_size = DEFAULT_SPAN; + unsigned long cache_total_size = 0; + + ret = get_cache_size(uparams->cpu, "L3", &cache_total_size); + if (ret) + return ret; + fill_buf.buf_size = cache_total_size * 2 > DEFAULT_SPAN ? + cache_total_size * 2 : DEFAULT_SPAN; fill_buf.memflush = 1; param.fill_buf = &fill_buf; } diff --git a/tools/testing/selftests/resctrl/mbm_test.c b/tools/testing/selftests/resctrl/mbm_test.c index b1f03a73333f..7635ee6b9339 100644 --- a/tools/testing/selftests/resctrl/mbm_test.c +++ b/tools/testing/selftests/resctrl/mbm_test.c @@ -149,7 +149,13 @@ static int mbm_run_test(const struct resctrl_test *test, const struct user_param fill_buf.memflush = uparams->fill_buf->memflush; param.fill_buf = &fill_buf; } else if (!uparams->benchmark_cmd[0]) { - fill_buf.buf_size = DEFAULT_SPAN; + unsigned long cache_total_size = 0; + + ret = get_cache_size(uparams->cpu, "L3", &cache_total_size); + if (ret) + return ret; + fill_buf.buf_size = cache_total_size * 2 > DEFAULT_SPAN ? + cache_total_size * 2 : DEFAULT_SPAN; fill_buf.memflush = 1; param.fill_buf = &fill_buf; }