From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D9657C433FE for ; Wed, 26 Oct 2022 04:37:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231706AbiJZEht (ORCPT ); Wed, 26 Oct 2022 00:37:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56924 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229753AbiJZEhr (ORCPT ); Wed, 26 Oct 2022 00:37:47 -0400 Received: from loongson.cn (mail.loongson.cn [114.242.206.163]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 3F53E74E00; Tue, 25 Oct 2022 21:37:44 -0700 (PDT) Received: from loongson.cn (unknown [113.200.148.30]) by gateway (Coremail) with SMTP id _____8Dx_7eXuVhjp4gCAA--.8046S3; Wed, 26 Oct 2022 12:37:43 +0800 (CST) Received: from [10.130.0.135] (unknown [113.200.148.30]) by localhost.localdomain (Coremail) with SMTP id AQAAf8CxqFeWuVhjWCYFAA--.1146S3; Wed, 26 Oct 2022 12:37:43 +0800 (CST) Subject: Re: [PATCH v3 2/3] perf bench syscall: Add close syscall benchmark To: Ian Rogers References: <1665042130-15786-1-git-send-email-yangtiezhu@loongson.cn> <1665042130-15786-3-git-send-email-yangtiezhu@loongson.cn> Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org From: Tiezhu Yang Message-ID: <6a2d2031-0773-e1af-027f-8939ce596d52@loongson.cn> Date: Wed, 26 Oct 2022 12:37:42 +0800 User-Agent: Mozilla/5.0 (X11; Linux mips64; rv:45.0) Gecko/20100101 Thunderbird/45.4.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit X-CM-TRANSID: AQAAf8CxqFeWuVhjWCYFAA--.1146S3 X-CM-SenderInfo: p1dqw3xlh2x3gn0dqz5rrqw2lrqou0/ X-Coremail-Antispam: 1Uk129KBjvJXoWxZr1DJryDtF4xKw1xZF13Jwb_yoW5uFy7pF 47Ca1Utw4rAF4jv3W3Jr4kXFyrJr12qF1YywnIkws8Zr13X3s0gayjgay5XFnruFW7K345 ua1vvry8WF4xZaDanT9S1TB71UUUUjUqnTZGkaVYY2UrUUUUj1kv1TuYvTs0mT0YCTnIWj qI5I8CrVACY4xI64kE6c02F40Ex7xfYxn0WfASr-VFAUDa7-sFnT9fnUUIcSsGvfJTRUUU bqxYFVCjjxCrM7AC8VAFwI0_Jr0_Gr1l1xkIjI8I6I8E6xAIw20EY4v20xvaj40_Wr0E3s 1l1IIY67AEw4v_JrI_Jryl8cAvFVAK0II2c7xJM28CjxkF64kEwVA0rcxSw2x7M28EF7xv wVC0I7IYx2IY67AKxVWUJVWUCwA2z4x0Y4vE2Ix0cI8IcVCY1x0267AKxVWUJVW8JwA2z4 x0Y4vEx4A2jsIE14v26r4UJVWxJr1l84ACjcxK6I8E87Iv6xkF7I0E14v26r4UJVWxJr1l n4kS14v26r1Y6r17M2AIxVAIcxkEcVAq07x20xvEncxIr21l57IF6xkI12xvs2x26I8E6x ACxx1l5I8CrVACY4xI64kE6c02F40Ex7xfMcIj6xIIjxv20xvE14v26r126r1DMcIj6I8E 87Iv67AKxVW8JVWxJwAm72CE4IkC6x0Yz7v_Jr0_Gr1lF7xvr2IY64vIr41lc7I2V7IY0V AS07AlzVAYIcxG8wCY1x0262kKe7AKxVWUAVWUtwCF04k20xvY0x0EwIxGrwCFx2IqxVCF s4IE7xkEbVWUJVW8JwCFI7km07C267AKxVWUXVWUAwC20s026c02F40E14v26r1j6r18MI 8I3I0E7480Y4vE14v26r106r1rMI8E67AF67kF1VAFwI0_Jw0_GFylIxkGc2Ij64vIr41l IxAIcVC0I7IYx2IY67AKxVWUJVWUCwCI42IY6xIIjxv20xvEc7CjxVAFwI0_Jr0_Gr1lIx AIcVCF04k26cxKx2IYs7xG6r1j6r1xMIIF0xvEx4A2jsIE14v26r1j6r4UMIIF0xvEx4A2 jsIEc7CjxVAFwI0_Jr0_GrUvcSsGvfC2KfnxnUUI43ZEXa7IU8RuWPUUUUU== Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/25/2022 11:37 PM, Ian Rogers wrote: > On Thu, Oct 6, 2022 at 12:42 AM Tiezhu Yang wrote: >> >> This commit adds a simple close syscall benchmark, more syscall >> benchmarks can be added in the future. >> ... >> diff --git a/tools/perf/bench/syscall.c b/tools/perf/bench/syscall.c >> index 746fd71..058394b 100644 >> --- a/tools/perf/bench/syscall.c >> +++ b/tools/perf/bench/syscall.c >> @@ -46,6 +46,9 @@ static int bench_syscall_common(int argc, const char **argv, int syscall) >> case __NR_getppid: >> getppid(); >> break; >> + case __NR_close: >> + close(dup(0)); > > Thanks for contributing! This benchmark will compute the cost of close > and dup, naively dup could perform memory allocation and be slow. > Perhaps a number of file descriptors could be made outside of the > timed region? > Hi Ian, Thanks for your review and suggestion. I tried the following changes based on this patchset, it shows "dup failed" due to the default number of "max open files" (ulimit -n) is 1024 but the loops is 10000000, if reduce the loops to 1000, the test time is too short and seems meaningless. diff --git a/tools/perf/bench/syscall.c b/tools/perf/bench/syscall.c index c8f8bee..76571a4 100644 --- a/tools/perf/bench/syscall.c +++ b/tools/perf/bench/syscall.c @@ -57,10 +57,26 @@ static int bench_syscall_common(int argc, const char **argv, int syscall) struct timeval start, stop, diff; unsigned long long result_usec = 0; const char *name = NULL; - int i; + int i, *fd = NULL; argc = parse_options(argc, argv, options, bench_syscall_usage, 0); + if (syscall == __NR_close) { + fd = (int *) malloc(sizeof(int) * loops); + if (fd == NULL) { + fprintf(stderr, "malloc failed\n"); + exit(1); + } + + for (i = 0; i < loops; i++) { + fd[i] = dup(i); + if (fd[i] < 0) { + fprintf(stderr, "dup failed\n"); + exit(1); + } + } + } + gettimeofday(&start, NULL); for (i = 0; i < loops; i++) { @@ -69,7 +85,7 @@ static int bench_syscall_common(int argc, const char **argv, int syscall) getppid(); break; case __NR_close: - close(dup(0)); + close(fd[i]); break; case __NR_execve: test_execve(); @@ -85,6 +101,9 @@ static int bench_syscall_common(int argc, const char **argv, int syscall) gettimeofday(&stop, NULL); timersub(&stop, &start, &diff); + if (syscall == __NR_close) + free(fd); + switch (syscall) { case __NR_getppid: name = "getppid()"; What about the following changes? Use "open" instead of "dup" to generate fd (it nees more test time), or just leave the code as it is? diff --git a/tools/perf/bench/syscall.c b/tools/perf/bench/syscall.c index c8f8bee..3aab5fd 100644 --- a/tools/perf/bench/syscall.c +++ b/tools/perf/bench/syscall.c @@ -57,7 +57,7 @@ static int bench_syscall_common(int argc, const char **argv, int syscall) struct timeval start, stop, diff; unsigned long long result_usec = 0; const char *name = NULL; - int i; + int i, fd; argc = parse_options(argc, argv, options, bench_syscall_usage, 0); @@ -69,7 +69,12 @@ static int bench_syscall_common(int argc, const char **argv, int syscall) getppid(); break; case __NR_close: - close(dup(0)); + fd = open("/etc/passwd", O_RDONLY); + if (fd < 0) { + fprintf(stderr, "open failed\n"); + exit(1); + } + close(fd); break; case __NR_execve: test_execve(); Thanks, Tiezhu