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 X-Spam-Level: X-Spam-Status: No, score=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 7729FC4338F for ; Fri, 20 Aug 2021 17:20:43 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id E666B611AD for ; Fri, 20 Aug 2021 17:20:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org E666B611AD Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=soleen.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 883A16B0072; Fri, 20 Aug 2021 13:20:42 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 833E76B0073; Fri, 20 Aug 2021 13:20:42 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 722B56B0074; Fri, 20 Aug 2021 13:20:42 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0241.hostedemail.com [216.40.44.241]) by kanga.kvack.org (Postfix) with ESMTP id 582046B0072 for ; Fri, 20 Aug 2021 13:20:42 -0400 (EDT) Received: from smtpin08.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 0584322887 for ; Fri, 20 Aug 2021 17:20:42 +0000 (UTC) X-FDA: 78496123524.08.5C03746 Received: from mail-ej1-f44.google.com (mail-ej1-f44.google.com [209.85.218.44]) by imf13.hostedemail.com (Postfix) with ESMTP id BFEF2101DD1B for ; Fri, 20 Aug 2021 17:20:41 +0000 (UTC) Received: by mail-ej1-f44.google.com with SMTP id x11so21742605ejv.0 for ; Fri, 20 Aug 2021 10:20:41 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=soleen.com; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=CSRFa71O1Abz3CtsCgtEjDNe3nuYOG3QUi11RU5JHrg=; b=aQy1+sd63YYpCZOrulJQMkLK2awdFz2FpqFEiZc3cIQG36r1DGK8GKykRKWbpi+OdG 9l73NdbHKb1W0J4nM8drPm0iwly+paS/Yhe/D4tQbjN8DZlNGW41FCX9QGZPmnqwz187 cFzmvZTmFfffU8nrlZILZIBcZtKBFAvbhWbzwsByCf/p0b4upgcpSDcnjOq75gZv5n5Y gqQkEeF/qhGwT2zsb69Qaz0+xFoTqocWJTUpSbxTAYuSpaaiWERnMwPuEMEJm5Bp45w8 7hP1aRMzD1pnkK8UDQP4pQ+4KxbAaIVAEVHe8FMU6Y7ft2zouKpCemINyHSe3Qsqa8fA FsCQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=CSRFa71O1Abz3CtsCgtEjDNe3nuYOG3QUi11RU5JHrg=; b=FvyGLIlmJaUrvQgGwhgjF9JP+fM9q9M8fu+kWIc0kLtGRCbMflkwQcnYjx1HqNWkVM A7MdLr4LF3Ldq6U/HVGdGUFAT3cuqwFeHna91B0lZpXClxQtVniGfLq8eARwYNy01Nmn RI3bgQqmRWgFWQ81fN09hvjRg1sqyZHszTuzlHeYz+TuFzMxkn1MsdJC1BmQAApL57h2 GUzM4nlcStf6U9v1pE3F5a0ROMyLytIauQQUT0nkz2+9SSK3vlJneCAe5jF4iTJvA+g1 1uN1f61uii07Syp4hL8FpPoN3Bh2E66mdpNgdvH5Mh/Z4y53n4nWigoKgGM8Xyy0F2OA 7TAw== X-Gm-Message-State: AOAM5337pCDrdqoVXD3SmkFPL+BMWOefWOevl/NvboaSdAXk5Z9tirj7 9eEpzVHfqWdd7lJwBGZn2bYzgh1KnVEZrc4BGfPXsA== X-Google-Smtp-Source: ABdhPJyvZorW7EcurksXyiF19X7N66fLf9JK5b88Zy4/UR6KRUufyUQzC7h0X45htFcDrhic1PId5LzO7MPkT7mVDJA= X-Received: by 2002:a17:907:f95:: with SMTP id kb21mr22991486ejc.541.1629480040739; Fri, 20 Aug 2021 10:20:40 -0700 (PDT) MIME-Version: 1.0 References: <1d03ee0d1b341959d4b61672c6401d498bff5652.1629386192.git.zhansayabagdaulet@gmail.com> <20210819163117.GO5469@sequoia> In-Reply-To: <20210819163117.GO5469@sequoia> From: Pavel Tatashin Date: Fri, 20 Aug 2021 13:20:04 -0400 Message-ID: Subject: Re: [PATCH v3 2/2] selftests: vm: add COW time test for KSM pages To: Tyler Hicks Cc: Zhansaya Bagdauletkyzy , Andrew Morton , linux-mm , linux-kselftest@vger.kernel.org, LKML Content-Type: text/plain; charset="UTF-8" Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=soleen.com header.s=google header.b=aQy1+sd6; spf=pass (imf13.hostedemail.com: domain of pasha.tatashin@soleen.com designates 209.85.218.44 as permitted sender) smtp.mailfrom=pasha.tatashin@soleen.com; dmarc=none X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: BFEF2101DD1B X-Stat-Signature: x88s6h7zshrx11eb94uszwq1agr6grbh X-HE-Tag: 1629480041-273112 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Aug 19, 2021 at 12:31 PM Tyler Hicks wrote: > > On 2021-08-19 21:33:43, Zhansaya Bagdauletkyzy wrote: > > 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 > > --- > > v2 -> v3: > > - address Tyler's feedback > > Thanks for incorporating my suggestions! I can confirm that my feedback > was completely addressed. > > Reviewed-by: Tyler Hicks > > Tyler Reviewed-by: Pavel Tatashin