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([140.113.216.168]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2dadc1104a3sm5398524a91.45.2024.09.08.19.19.41 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 08 Sep 2024 19:19:42 -0700 (PDT) From: Kuan-Wei Chiu To: libc-alpha@sourceware.org Cc: goldstein.w.n@gmail.com, jserv@ccns.ncku.edu.tw, Kuan-Wei Chiu Subject: [PATCH v6 1/2] benchtests: Add benchmark test for bsearch Date: Mon, 9 Sep 2024 10:19:16 +0800 Message-Id: <20240909021917.3159077-2-visitorckw@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240909021917.3159077-1-visitorckw@gmail.com> References: <20240909021917.3159077-1-visitorckw@gmail.com> MIME-Version: 1.0 X-Spam-Status: No, score=-10.6 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, GIT_PATCH_0, KAM_SHORT, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: libc-alpha-bounces~incoming=patchwork.ozlabs.org@sourceware.org Introduce a benchmark test for the bsearch function to evaluate its performance. Signed-off-by: Kuan-Wei Chiu --- Changes in v6: - Add 'nmemb' field to the 'results' array. benchtests/Makefile | 1 + benchtests/bench-bsearch.c | 137 +++++++++++++++++++++++++++++++++++++ 2 files changed, 138 insertions(+) create mode 100644 benchtests/bench-bsearch.c diff --git a/benchtests/Makefile b/benchtests/Makefile index d228e9e68a..955b766756 100644 --- a/benchtests/Makefile +++ b/benchtests/Makefile @@ -253,6 +253,7 @@ hash-benchset := \ stdlib-benchset := \ arc4random \ + bsearch \ random-lock \ strtod \ # stdlib-benchset diff --git a/benchtests/bench-bsearch.c b/benchtests/bench-bsearch.c new file mode 100644 index 0000000000..8f88a1929c --- /dev/null +++ b/benchtests/bench-bsearch.c @@ -0,0 +1,137 @@ +/* Measure bsearch functions. + Copyright (C) 2022-2024 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + . */ + +#define TEST_MAIN +#define TEST_NAME "bsearch" + +#define ARRAY_SIZE 100000 +#define LOOP_ITERS 100000000 + +/* Directly including leads to the use of an inline version + of bsearch(), which may cause our test cases to be optimized away by + the compiler due to predictability. To address this, we should + include directly and replace __extern_inline + with __attribute__((noinline)) to ensure the compiler does not + inline the function. Additionally, we need to add some macros + required for compilation. */ +#include +#define __extern_inline __attribute__((noinline)) +#define __GNUC_PREREQ(x, y) 0 +typedef int (*__compar_fn_t) (const void *, const void *); +#include +#undef __extern_inline +#undef __GNUC_PREREQ + +#include "json-lib.h" +#include "bench-timing.h" + +int arr[ARRAY_SIZE]; + +static int +comp_asc (const void *p1, const void *p2) +{ + int x1 = *(int *) p1; + int x2 = *(int *) p2; + + if (x1 < x2) + return -1; + if (x1 > x2) + return 1; + return 0; +} + +static int +comp_desc (const void *p1, const void *p2) +{ + int x1 = *(int *) p1; + int x2 = *(int *) p2; + + if (x1 > x2) + return -1; + if (x1 < x2) + return 1; + return 0; +} + +static void +do_bench (json_ctx_t *json_ctx, bool ascending, bool contained) +{ + size_t i, iters = LOOP_ITERS; + timing_t start, stop, cur; + int key; + volatile __attribute__((__unused__)) void *res; + + for (i = 0; i < ARRAY_SIZE; ++i) + { + arr[i] = (ascending ? i : ARRAY_SIZE - 1 - i) << 1; + } + + json_element_object_begin (json_ctx); + json_attr_uint (json_ctx, "array-size", ARRAY_SIZE); + json_attr_string (json_ctx, "key-pattern", ascending ? "ascending" : "descending"); + json_attr_string (json_ctx, "contained", contained ? "yes" : "no"); + json_attr_string (json_ctx, "simple", "yes"); + json_attr_uint (json_ctx, "nmemb", ARRAY_SIZE); + + TIMING_NOW (start); + + for (i = 0; i < iters; ++i) + { + key = (i % ARRAY_SIZE << 1) + !contained; + res = bsearch(&key, arr, ARRAY_SIZE, sizeof(arr[0]), ascending ? comp_asc : comp_desc); + } + + TIMING_NOW (stop); + + TIMING_DIFF (cur, start, stop); + + json_attr_double (json_ctx, "timing", (double) cur / (double) iters); + json_element_object_end (json_ctx); +} + +int +do_test (void) +{ + json_ctx_t json_ctx; + + json_init (&json_ctx, 0, stdout); + + json_document_begin (&json_ctx); + json_attr_string (&json_ctx, "timing_type", TIMING_TYPE); + json_attr_object_begin (&json_ctx, "functions"); + json_attr_object_begin (&json_ctx, TEST_NAME); + json_attr_string (&json_ctx, "bench-variant", "default"); + json_array_begin (&json_ctx, "results"); + + for (int ascending = 0; ascending < 2; ++ascending) + { + for (int contained = 0; contained < 2; ++contained) + { + do_bench(&json_ctx, ascending, contained); + } + } + + json_array_end (&json_ctx); + json_attr_object_end (&json_ctx); + json_attr_object_end (&json_ctx); + json_document_end (&json_ctx); + + return 0; +} + +#include From patchwork Mon Sep 9 02:19:17 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kuan-Wei Chiu X-Patchwork-Id: 1982291 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20230601 header.b=gIrefIr0; dkim-atps=neutral Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=sourceware.org (client-ip=8.43.85.97; helo=server2.sourceware.org; envelope-from=libc-alpha-bounces~incoming=patchwork.ozlabs.org@sourceware.org; receiver=patchwork.ozlabs.org) Received: from server2.sourceware.org (server2.sourceware.org [8.43.85.97]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (secp384r1) server-digest SHA384) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4X29Y55FSXz1y1C for ; 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([140.113.216.168]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2dadc1104a3sm5398524a91.45.2024.09.08.19.19.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 08 Sep 2024 19:19:52 -0700 (PDT) From: Kuan-Wei Chiu To: libc-alpha@sourceware.org Cc: goldstein.w.n@gmail.com, jserv@ccns.ncku.edu.tw, Kuan-Wei Chiu Subject: [PATCH v6 2/2] Optimize bsearch() implementation for performance Date: Mon, 9 Sep 2024 10:19:17 +0800 Message-Id: <20240909021917.3159077-3-visitorckw@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240909021917.3159077-1-visitorckw@gmail.com> References: <20240909021917.3159077-1-visitorckw@gmail.com> MIME-Version: 1.0 X-Spam-Status: No, score=-10.7 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=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: libc-alpha-bounces~incoming=patchwork.ozlabs.org@sourceware.org Optimize the bsearch() function to improve binary search performance. Although the code size grew by 8 bytes, the new implementation achieves a 15% reduction in execution time on my x86 machine, according to the bench-bsearch benchmark results. Signed-off-by: Kuan-Wei Chiu Reviewed-by: Noah Goldstein --- bits/stdlib-bsearch.h | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-) diff --git a/bits/stdlib-bsearch.h b/bits/stdlib-bsearch.h index 540d718952..57f060b504 100644 --- a/bits/stdlib-bsearch.h +++ b/bits/stdlib-bsearch.h @@ -20,22 +20,14 @@ __extern_inline void * bsearch (const void *__key, const void *__base, size_t __nmemb, size_t __size, __compar_fn_t __compar) { - size_t __l, __u, __idx; const void *__p; int __comparison; - __l = 0; - __u = __nmemb; - while (__l < __u) + while (__nmemb) { - __idx = (__l + __u) / 2; - __p = (const void *) (((const char *) __base) + (__idx * __size)); + __p = (const void *) (((const char *) __base) + ((__nmemb >> 1) * __size)); __comparison = (*__compar) (__key, __p); - if (__comparison < 0) - __u = __idx; - else if (__comparison > 0) - __l = __idx + 1; - else + if (__comparison == 0) { #if __GNUC_PREREQ(4, 6) # pragma GCC diagnostic push @@ -46,6 +38,12 @@ bsearch (const void *__key, const void *__base, size_t __nmemb, size_t __size, # pragma GCC diagnostic pop #endif } + if (__comparison > 0) + { + __base = ((const char *) __p) + __size; + --__nmemb; + } + __nmemb >>= 1; } return NULL;