From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by gabe.freedesktop.org (Postfix) with ESMTPS id 68FED6E439 for ; Mon, 2 Nov 2020 09:03:06 +0000 (UTC) From: Anand Moon Date: Mon, 2 Nov 2020 09:02:43 +0000 Message-Id: <20201102090243.19737-1-anandx.ram.moon@intel.com> MIME-Version: 1.0 Subject: [igt-dev] [i-g-t] tests/kms_setmode: basic Improve accuracy with using of confidence interval List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: igt-dev-bounces@lists.freedesktop.org Sender: "igt-dev" To: igt-dev@lists.freedesktop.org, Dorota Czaplejewicz Cc: Anand Moon List-ID: Using confidence interval formula accuracy is estimates approximately at 95% when {X} is the average of a sample of size n. Use this confidence interval formula as used in statistics to estimate the accuracy. Cc: Dorota Czaplejewicz Signed-off-by: Anand Moon --- See below link. https://en.wikipedia.org/wiki/68%E2%80%9395%E2%80%9399.7_rule#Cumulative_distribution_function --- tests/kms_setmode.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tests/kms_setmode.c b/tests/kms_setmode.c index 92f3ead2..58814a13 100644 --- a/tests/kms_setmode.c +++ b/tests/kms_setmode.c @@ -494,7 +494,7 @@ static void check_timings(int crtc_idx, const drmModeModeInfo *kmode) * which depend on timing, giving the lowest acceptable MTBF of 5.6s * for 60Hz sampling rate. */ - accuracy = 3. * stddev; + accuracy = 3. * stddev / sqrt(CALIBRATE_TS_STEPS); igt_info("Expected frametime: %.0fus; measured %.1fus +- %.3fus accuracy %.2f%% [%.2f scanlines]\n", expected, mean, stddev, -- 2.25.1 _______________________________________________ igt-dev mailing list igt-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/igt-dev