From patchwork Fri Oct 18 02:33:27 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Reinette Chatre X-Patchwork-Id: 836902 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.7]) (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 89B4B188012; Fri, 18 Oct 2024 02:22:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.7 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729218167; cv=none; b=V4OwmjKr5+oAkR9aasX4ebfnxHEtdZbX4Axs46jkpUpjvvFqOXPpoSvHyzhp0eOAggbzWO/6exUPLidFq2sApaQ+9jw+lkqSkbHveBqwomG/hJMqHBGksQrJkNEgsj2oJ+A/nLAta1DxTT1jJTlH2s3+KnhdH3FpkCNBMij28Tc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729218167; c=relaxed/simple; bh=LF2o/Era7xSNvAB0Kk818hm/mieubwe/KElr/Vt+Yrg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=UZmgtcbK1aH9s6gf2SH4eY5t5mSfakUTAvbqWrEkmXtWrJsS7nQeEWbEb2oITIC7ICZ1p1IWWUDXD38DKzd/aUdou0DyUknON2p9HJROZbnOZ/CpWx55D00ZSL9cpRJD4RwcUwPp9DqNrrgE2RvIyxuNHmzxp7iVGsxZO8vHnnQ= 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=Bssk2wt/; arc=none smtp.client-ip=192.198.163.7 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="Bssk2wt/" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1729218166; x=1760754166; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=LF2o/Era7xSNvAB0Kk818hm/mieubwe/KElr/Vt+Yrg=; b=Bssk2wt/5+BBZC2m6G1Qpwvqiz86nvl9nmbfCvXIVJ7/gO+o8er+0Gzt 9ArzQLaIgRzYAipBAefPmh8AorQvjLIOMzip6FtwCmOQkvQ8bmsxJoAEi wT+b0uGdX3rhY1YrTtp+MtO7BlLPojqLlMsKXfCL/ysvZcyeEPzmSMXU8 n5dTNBua7HsQ249S1aTzVOtqRcmh9SXbWLJI5a1tEx7gi2oi7vf4pvjVU fHaVUD8YyXFwUsW7qp0AvdldbxYVDI7aR1vpNQnK2IBpOv4JQoziGybK9 8G9b+GiAjfUd0cJS/8/DGmuuz6DFkonVWJ02eh9er3gUKoP34JTHU297w A==; X-CSE-ConnectionGUID: l+ZA4yaURSqE7EuYrKq1Cg== X-CSE-MsgGUID: LBolW/dIQYaM9WY1mqeNUA== X-IronPort-AV: E=McAfee;i="6700,10204,11228"; a="54149720" X-IronPort-AV: E=Sophos;i="6.11,212,1725346800"; d="scan'208";a="54149720" Received: from orviesa010.jf.intel.com ([10.64.159.150]) by fmvoesa101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Oct 2024 19:22:38 -0700 X-CSE-ConnectionGUID: 7SRKs+ZNRDmg0VmC5TZpjw== X-CSE-MsgGUID: KLZW7h8zS5SbNpsazrYVrA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.11,212,1725346800"; d="scan'208";a="78697734" Received: from rchatre-desk1.jf.intel.com ([10.165.154.99]) by orviesa010-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Oct 2024 19:22:37 -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 V3 12/15] selftests/resctrl: Use cache size to determine "fill_buf" buffer size Date: Thu, 17 Oct 2024 19:33:27 -0700 Message-ID: <388c93423d9a071f5877f3edb4f55ef64bf384bc.1729218182.git.reinette.chatre@intel.com> X-Mailer: git-send-email 2.46.2 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, now renamed to MINIMUM_SPAN, that has been appropriate for testing so far. Signed-off-by: Reinette Chatre Reviewed-by: Ilpo Järvinen --- Changes since V2: - Move duplicate code into helper. (Ilpo) - Rename DEFAULT_SPAN to MINIMUM_SPAN to reflect its new purpose. (Ilpo) - Do _not_ add Ilpo's Reviewed-by tag ... the patch changed too much. 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/fill_buf.c | 13 +++++++++++++ tools/testing/selftests/resctrl/mba_test.c | 7 ++++++- tools/testing/selftests/resctrl/mbm_test.c | 7 ++++++- tools/testing/selftests/resctrl/resctrl.h | 3 ++- tools/testing/selftests/resctrl/resctrl_tests.c | 2 +- 5 files changed, 28 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/resctrl/fill_buf.c b/tools/testing/selftests/resctrl/fill_buf.c index 380cc35f10c6..19a01a52dc1a 100644 --- a/tools/testing/selftests/resctrl/fill_buf.c +++ b/tools/testing/selftests/resctrl/fill_buf.c @@ -129,3 +129,16 @@ unsigned char *alloc_buffer(size_t buf_size, bool memflush) return buf; } + +ssize_t get_fill_buf_size(int cpu_no, const char *cache_type) +{ + unsigned long cache_total_size = 0; + int ret; + + ret = get_cache_size(cpu_no, cache_type, &cache_total_size); + if (ret) + return ret; + + return cache_total_size * 2 > MINIMUM_SPAN ? + cache_total_size * 2 : MINIMUM_SPAN; +} diff --git a/tools/testing/selftests/resctrl/mba_test.c b/tools/testing/selftests/resctrl/mba_test.c index 74d95c460bd0..bf37f3555660 100644 --- a/tools/testing/selftests/resctrl/mba_test.c +++ b/tools/testing/selftests/resctrl/mba_test.c @@ -182,7 +182,12 @@ 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; + ssize_t buf_size; + + buf_size = get_fill_buf_size(uparams->cpu, "L3"); + if (buf_size < 0) + return buf_size; + fill_buf.buf_size = buf_size; fill_buf.memflush = true; param.fill_buf = &fill_buf; } diff --git a/tools/testing/selftests/resctrl/mbm_test.c b/tools/testing/selftests/resctrl/mbm_test.c index 72261413c868..4224f8ce3538 100644 --- a/tools/testing/selftests/resctrl/mbm_test.c +++ b/tools/testing/selftests/resctrl/mbm_test.c @@ -149,7 +149,12 @@ 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; + ssize_t buf_size; + + buf_size = get_fill_buf_size(uparams->cpu, "L3"); + if (buf_size < 0) + return buf_size; + fill_buf.buf_size = buf_size; fill_buf.memflush = true; param.fill_buf = &fill_buf; } diff --git a/tools/testing/selftests/resctrl/resctrl.h b/tools/testing/selftests/resctrl/resctrl.h index 032cd9ebd761..a553fe975938 100644 --- a/tools/testing/selftests/resctrl/resctrl.h +++ b/tools/testing/selftests/resctrl/resctrl.h @@ -41,7 +41,7 @@ #define BENCHMARK_ARGS 64 -#define DEFAULT_SPAN (250 * MB) +#define MINIMUM_SPAN (250 * MB) /* * fill_buf_param: "fill_buf" benchmark parameters @@ -169,6 +169,7 @@ int perf_event_open(struct perf_event_attr *hw_event, pid_t pid, int cpu, unsigned char *alloc_buffer(size_t buf_size, bool memflush); void mem_flush(unsigned char *buf, size_t buf_size); void fill_cache_read(unsigned char *buf, size_t buf_size, bool once); +ssize_t get_fill_buf_size(int cpu_no, const char *cache_type); int initialize_read_mem_bw_imc(void); int measure_read_mem_bw(const struct user_params *uparams, struct resctrl_val_param *param, pid_t bm_pid); diff --git a/tools/testing/selftests/resctrl/resctrl_tests.c b/tools/testing/selftests/resctrl/resctrl_tests.c index 88768f4d4961..790f4eb7871a 100644 --- a/tools/testing/selftests/resctrl/resctrl_tests.c +++ b/tools/testing/selftests/resctrl/resctrl_tests.c @@ -189,7 +189,7 @@ static struct fill_buf_param *alloc_fill_buf_param(struct user_params *uparams) ksft_exit_skip("Unable to parse benchmark buffer size.\n"); } } else { - fill_param->buf_size = DEFAULT_SPAN; + fill_param->buf_size = MINIMUM_SPAN; } if (uparams->benchmark_cmd[2]) {