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[130.126.255.38]) by smtp.googlemail.com with ESMTPSA id s5sm6048022ilq.59.2021.09.18.14.39.53 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 18 Sep 2021 14:39:54 -0700 (PDT) To: libc-alpha@sourceware.org Subject: [PATCH v1] benchtests: Improve reliability of memcmp benchmarks Date: Sat, 18 Sep 2021 16:39:47 -0500 Message-Id: <20210918213947.2426144-1-goldstein.w.n@gmail.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 X-Spam-Status: No, score=-12.0 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-Patchwork-Original-From: Noah Goldstein via Libc-alpha From: Noah Goldstein Reply-To: Noah Goldstein Errors-To: libc-alpha-bounces+patchwork=sourceware.org@sourceware.org Sender: "Libc-alpha" No bug. Remove reallocation of bufs between implementation tests. Move initialization outside of foreach implementation test loop. Increase iteration count. Generally before this commit was seeing a great deal of variability between runs. The goal of this commit is to make the results more reliable. Benchtests build and bench-memcmp succeeding. Reviewed-by: H.J. Lu --- benchtests/bench-memcmp.c | 21 ++++++++++----------- 1 file changed, 10 insertions(+), 11 deletions(-) diff --git a/benchtests/bench-memcmp.c b/benchtests/bench-memcmp.c index 744c7ec5ba..0d6a93bf29 100644 --- a/benchtests/bench-memcmp.c +++ b/benchtests/bench-memcmp.c @@ -63,7 +63,7 @@ static void do_one_test (json_ctx_t *json_ctx, impl_t *impl, const CHAR *s1, const CHAR *s2, size_t len, int exp_result) { - size_t i, iters = INNER_LOOP_ITERS8; + size_t i, iters = INNER_LOOP_ITERS_LARGE; timing_t start, stop, cur; TIMING_NOW (start); @@ -103,20 +103,19 @@ do_test (json_ctx_t *json_ctx, size_t align1, size_t align2, size_t len, json_attr_uint (json_ctx, "result", (double) exp_result); json_array_begin (json_ctx, "timings"); - FOR_EACH_IMPL (impl, 0) - { - s1 = (CHAR *) (buf1 + align1); - s2 = (CHAR *) (buf2 + align2); + s1 = (CHAR *)(buf1 + align1); + s2 = (CHAR *)(buf2 + align2); - for (i = 0; i < len; i++) - s1[i] = s2[i] = 1 + (23 << ((CHARBYTES - 1) * 8)) * i % MAX_CHAR; + for (i = 0; i < len; i++) + s1[i] = s2[i] = 1 + (23 << ((CHARBYTES - 1) * 8)) * i % MAX_CHAR; - s1[len] = align1; - s2[len] = align2; - s2[len - 1] -= exp_result; + s1[len] = align1; + s2[len] = align2; + s2[len - 1] -= exp_result; + FOR_EACH_IMPL (impl, 0) + { do_one_test (json_ctx, impl, s1, s2, len, exp_result); - alloc_bufs (); } json_array_end (json_ctx);