From patchwork Thu Aug 19 15:33:43 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zhansaya Bagdauletkyzy X-Patchwork-Id: 499995 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4073DC00144 for ; Thu, 19 Aug 2021 15:33:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 21C286056B for ; Thu, 19 Aug 2021 15:33:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240423AbhHSPe0 (ORCPT ); Thu, 19 Aug 2021 11:34:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58790 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239964AbhHSPeY (ORCPT ); Thu, 19 Aug 2021 11:34:24 -0400 Received: from mail-lf1-x133.google.com (mail-lf1-x133.google.com [IPv6:2a00:1450:4864:20::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A96ECC061756; Thu, 19 Aug 2021 08:33:47 -0700 (PDT) Received: by mail-lf1-x133.google.com with SMTP id y34so13826091lfa.8; Thu, 19 Aug 2021 08:33:47 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=M9TwSY87XAPhsvv2+xxIfYeMLjCXKXv7wr0r+bI19IM=; b=Auj5nFOfwnF84p9IhpQf8B73+bLc3JiaXgIxjEJZW5fxWmo/rTvcApGRzrv3vs4wTD TcTBbH+b+cWPao9aAWdTy4bN8usIV34VvtzdUIr5bwQD+CE9BqksH6vq+sLxB+pIo0sB LURT5mNVW18p5vX8O2aXysrvxllRFVLlqPMjENJwWlbatLbwsi8BieJ9THdDWtEJA4hy pZjbw4x/vpAybpJ1z9hHelA5A1be2UTr46QhraFKcSbGkedx7zW6BfKgdnWqyLLxT4s/ TMFuXx7UHe1HPfWP5dRdZt885pvbJGUaK8+wNhrnsRD/mBbERR1ggb3Xsp5Jc2THAH8/ 1wRg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=M9TwSY87XAPhsvv2+xxIfYeMLjCXKXv7wr0r+bI19IM=; b=JvkXJfdMGLMQbO9vJbSP2NP2lFEjSaANOcIcJ/WPJjjYv4omUaR+Sdr19uUPna1Tg7 fcquzhoIi5n2nEakmAvIoJ0qr/rqzFl3P0zhYZNnEt0BsbvNc8Aw/Ip0PkHb3b7eNQCE HiKxGj+hJHCfIFth5xGRrySAxb/FCP46e1VtLcpxiFr17zcsjlbTk28bCDTO9trbt5sC j/rhnzsQ/SH8OiE1qm0adLFuXlsbtgIICLzEBsaJVKkj5bnPu/reKqWwgJZvEHnehkGZ cbDItHIgStnpcUnAyQ16ZXKoNPq2Ot5nU4WjZHk69GwXUkBIfsvimgBLrBrJe+yJTbh6 cRZw== X-Gm-Message-State: AOAM532o9LcwUBCcJwk2XvN4jRKMKL7OTK++I3ZonwMt4WlSH2e08vQQ AcdGFbLGZ1ga0J9UbFDPjGc= X-Google-Smtp-Source: ABdhPJwV83dZgXtO9SqMV+K96TQ39E7SH5UJ/EaqM3sJRcQn6I+4i3Lbsb8UskmduXxAVGb4vS88sw== X-Received: by 2002:a05:6512:3f9f:: with SMTP id x31mr10682570lfa.245.1629387226058; Thu, 19 Aug 2021 08:33:46 -0700 (PDT) Received: from asus ([147.30.82.254]) by smtp.gmail.com with ESMTPSA id u3sm281964lju.107.2021.08.19.08.33.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 19 Aug 2021 08:33:45 -0700 (PDT) Date: Thu, 19 Aug 2021 21:33:43 +0600 From: Zhansaya Bagdauletkyzy To: akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, tyhicks@linux.microsoft.com, pasha.tatashin@soleen.com Subject: [PATCH v3 2/2] selftests: vm: add COW time test for KSM pages Message-ID: <1d03ee0d1b341959d4b61672c6401d498bff5652.1629386192.git.zhansayabagdaulet@gmail.com> References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org Since merged pages are copied every time they need to be modified, the write access time is different between shared and non-shared pages. Add ksm_cow_time() function which evaluates latency of these COW breaks. First, 4000 pages are allocated and the time, required to modify 1 byte in every other page, is measured. After this, the pages are merged into 2000 pairs and in each pair, 1 page is modified (i.e. they are decoupled) to detect COW breaks. The time needed to break COW of merged pages is then compared with performance of non-shared pages. The test is run as follows: ./ksm_tests -C The output: Total size: 15 MiB Not merged pages: Total time: 0.002185489 s Average speed: 3202.945 MiB/s Merged pages: Total time: 0.004386872 s Average speed: 1595.670 MiB/s Signed-off-by: Zhansaya Bagdauletkyzy Reviewed-by: Pavel Tatashin --- v2 -> v3: - address Tyler's feedback Tyler's comments: https://lkml.org/lkml/2021/8/16/931 v1 -> v2: As suggested by Pavel, - add baseline figures with non-shared pages - instead of having all pages merged together, create pairs of duplicated pages Pavel's comments: https://lkml.org/lkml/2021/8/3/1363 tools/testing/selftests/vm/ksm_tests.c | 86 +++++++++++++++++++++++++- 1 file changed, 83 insertions(+), 3 deletions(-) diff --git a/tools/testing/selftests/vm/ksm_tests.c b/tools/testing/selftests/vm/ksm_tests.c index 432dfe615e50..c14927417759 100644 --- a/tools/testing/selftests/vm/ksm_tests.c +++ b/tools/testing/selftests/vm/ksm_tests.c @@ -33,7 +33,8 @@ enum ksm_test_name { CHECK_KSM_UNMERGE, CHECK_KSM_ZERO_PAGE_MERGE, CHECK_KSM_NUMA_MERGE, - KSM_MERGE_TIME + KSM_MERGE_TIME, + KSM_COW_TIME }; static int ksm_write_sysfs(const char *file_path, unsigned long val) @@ -98,7 +99,8 @@ static void print_help(void) " -U (page unmerging)\n" " -P evaluate merging time and speed.\n" " For this test, the size of duplicated memory area (in MiB)\n" - " must be provided using -s option\n\n"); + " must be provided using -s option\n" + " -C evaluate the time required to break COW of merged pages.\n\n"); printf(" -a: specify the access protections of pages.\n" " must be of the form [rwx].\n" @@ -455,6 +457,77 @@ static int ksm_merge_time(int mapping, int prot, int timeout, size_t map_size) return KSFT_FAIL; } +static int ksm_cow_time(int mapping, int prot, int timeout, size_t page_size) +{ + void *map_ptr; + struct timespec start_time, end_time; + unsigned long cow_time_ns; + + /* page_count must be less than 2*page_size */ + size_t page_count = 4000; + + map_ptr = allocate_memory(NULL, prot, mapping, '*', page_size * page_count); + if (!map_ptr) + return KSFT_FAIL; + + if (clock_gettime(CLOCK_MONOTONIC_RAW, &start_time)) { + perror("clock_gettime"); + return KSFT_FAIL; + } + for (size_t i = 0; i < page_count - 1; i = i + 2) + memset(map_ptr + page_size * i, '-', 1); + if (clock_gettime(CLOCK_MONOTONIC_RAW, &end_time)) { + perror("clock_gettime"); + return KSFT_FAIL; + } + + cow_time_ns = (end_time.tv_sec - start_time.tv_sec) * NSEC_PER_SEC + + (end_time.tv_nsec - start_time.tv_nsec); + + printf("Total size: %lu MiB\n\n", (page_size * page_count) / MB); + printf("Not merged pages:\n"); + printf("Total time: %ld.%09ld s\n", cow_time_ns / NSEC_PER_SEC, + cow_time_ns % NSEC_PER_SEC); + printf("Average speed: %.3f MiB/s\n\n", ((page_size * (page_count / 2)) / MB) / + ((double)cow_time_ns / NSEC_PER_SEC)); + + /* Create 2000 pairs of duplicate pages */ + for (size_t i = 0; i < page_count - 1; i = i + 2) { + memset(map_ptr + page_size * i, '+', i / 2 + 1); + memset(map_ptr + page_size * (i + 1), '+', i / 2 + 1); + } + if (ksm_merge_pages(map_ptr, page_size * page_count, start_time, timeout)) + goto err_out; + + if (clock_gettime(CLOCK_MONOTONIC_RAW, &start_time)) { + perror("clock_gettime"); + goto err_out; + } + for (size_t i = 0; i < page_count - 1; i = i + 2) + memset(map_ptr + page_size * i, '-', 1); + if (clock_gettime(CLOCK_MONOTONIC_RAW, &end_time)) { + perror("clock_gettime"); + goto err_out; + } + + cow_time_ns = (end_time.tv_sec - start_time.tv_sec) * NSEC_PER_SEC + + (end_time.tv_nsec - start_time.tv_nsec); + + printf("Merged pages:\n"); + printf("Total time: %ld.%09ld s\n", cow_time_ns / NSEC_PER_SEC, + cow_time_ns % NSEC_PER_SEC); + printf("Average speed: %.3f MiB/s\n", ((page_size * (page_count / 2)) / MB) / + ((double)cow_time_ns / NSEC_PER_SEC)); + + munmap(map_ptr, page_size * page_count); + return KSFT_PASS; + +err_out: + printf("Not OK\n"); + munmap(map_ptr, page_size * page_count); + return KSFT_FAIL; +} + int main(int argc, char *argv[]) { int ret, opt; @@ -468,7 +541,7 @@ int main(int argc, char *argv[]) bool merge_across_nodes = KSM_MERGE_ACROSS_NODES_DEFAULT; long size_MB = 0; - while ((opt = getopt(argc, argv, "ha:p:l:z:m:s:MUZNP")) != -1) { + while ((opt = getopt(argc, argv, "ha:p:l:z:m:s:MUZNPC")) != -1) { switch (opt) { case 'a': prot = str_to_prot(optarg); @@ -522,6 +595,9 @@ int main(int argc, char *argv[]) case 'P': test_name = KSM_MERGE_TIME; break; + case 'C': + test_name = KSM_COW_TIME; + break; default: return KSFT_FAIL; } @@ -571,6 +647,10 @@ int main(int argc, char *argv[]) ret = ksm_merge_time(MAP_PRIVATE | MAP_ANONYMOUS, prot, ksm_scan_limit_sec, size_MB); break; + case KSM_COW_TIME: + ret = ksm_cow_time(MAP_PRIVATE | MAP_ANONYMOUS, prot, ksm_scan_limit_sec, + page_size); + break; } if (ksm_restore(&ksm_sysfs_old)) {