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From:   =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>
To:     linux-kselftest@vger.kernel.org,
        Reinette Chatre <reinette.chatre@intel.com>,
        Shuah Khan <shuah@kernel.org>,
        Shaopeng Tan <tan.shaopeng@jp.fujitsu.com>,
        Fenghua Yu <fenghua.yu@intel.com>,
        Maciej Wieczor-Retman <maciej.wieczor-retman@intel.com>,
        linux-kernel@vger.kernel.org
Cc:     =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>
Subject: [PATCH v5 18/19] selftests/resctrl: Pass the real number of tests to show_cache_info()
Date:   Mon, 17 Jul 2023 16:15:06 +0300
Message-Id: <20230717131507.32420-19-ilpo.jarvinen@linux.intel.com>
In-Reply-To: <20230717131507.32420-1-ilpo.jarvinen@linux.intel.com>
References: <20230717131507.32420-1-ilpo.jarvinen@linux.intel.com>
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Results include warm-up test which is discarded before passing the sum
to show_cache_info(). show_cache_info() handles this by subtracting one
from the number of tests in divisor. It is a trappy construct to have
sum and number of tests parameters to disagree like this.

A more logical place for subtracting the skipped tests is where the sum
is calculated so move it there. Pass the correct number of tests to
show_cache_info() so it can be used directly as the divisor for
calculating the average.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
---
 tools/testing/selftests/resctrl/cache.c    | 2 +-
 tools/testing/selftests/resctrl/cat_test.c | 2 +-
 tools/testing/selftests/resctrl/cmt_test.c | 2 +-
 3 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/resctrl/cache.c b/tools/testing/selftests/resctrl/cache.c
index 9c0e4ce4f28e..18ebd1324cb3 100644
--- a/tools/testing/selftests/resctrl/cache.c
+++ b/tools/testing/selftests/resctrl/cache.c
@@ -294,7 +294,7 @@ int show_cache_info(unsigned long sum_llc_val, int no_of_bits,
 	long avg_diff = 0;
 	int ret;
 
-	avg_llc_val = sum_llc_val / (num_of_runs - 1);
+	avg_llc_val = sum_llc_val / num_of_runs;
 	avg_diff = (long)abs(cache_span - avg_llc_val);
 	diff_percent = ((float)cache_span - avg_llc_val) / cache_span * 100;
 
diff --git a/tools/testing/selftests/resctrl/cat_test.c b/tools/testing/selftests/resctrl/cat_test.c
index ed6c8e64ad11..3848dfb46aba 100644
--- a/tools/testing/selftests/resctrl/cat_test.c
+++ b/tools/testing/selftests/resctrl/cat_test.c
@@ -77,7 +77,7 @@ static int check_results(struct resctrl_val_param *param)
 	no_of_bits = count_bits(param->mask);
 
 	return show_cache_info(sum_llc_perf_miss, no_of_bits, param->span / 64,
-			       MAX_DIFF, MAX_DIFF_PERCENT, NUM_OF_RUNS,
+			       MAX_DIFF, MAX_DIFF_PERCENT, runs - 1,
 			       get_vendor() == ARCH_INTEL, false);
 }
 
diff --git a/tools/testing/selftests/resctrl/cmt_test.c b/tools/testing/selftests/resctrl/cmt_test.c
index 0ac9d6bbd13d..cb2197647c6c 100644
--- a/tools/testing/selftests/resctrl/cmt_test.c
+++ b/tools/testing/selftests/resctrl/cmt_test.c
@@ -59,7 +59,7 @@ static int check_results(struct resctrl_val_param *param, int no_of_bits)
 	fclose(fp);
 
 	return show_cache_info(sum_llc_occu_resc, no_of_bits, param->span,
-			       MAX_DIFF, MAX_DIFF_PERCENT, NUM_OF_RUNS,
+			       MAX_DIFF, MAX_DIFF_PERCENT, runs - 1,
 			       true, true);
 }
 
-- 
2.30.2