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=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 87AFFC4338F for ; Fri, 20 Aug 2021 17:20:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6D370611AD for ; Fri, 20 Aug 2021 17:20:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233512AbhHTRVZ (ORCPT ); Fri, 20 Aug 2021 13:21:25 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47170 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232598AbhHTRVU (ORCPT ); Fri, 20 Aug 2021 13:21:20 -0400 Received: from mail-ej1-x62c.google.com (mail-ej1-x62c.google.com [IPv6:2a00:1450:4864:20::62c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 31EA7C061756 for ; Fri, 20 Aug 2021 10:20:42 -0700 (PDT) Received: by mail-ej1-x62c.google.com with SMTP id bq25so21532665ejb.11 for ; Fri, 20 Aug 2021 10:20:42 -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=D3D9ppoomILsa9jLhBiNZwZaEInxxYCzC52Or3Myic1zA4ZADCiknJREtqbLy5va8W 1MLNrQ05EatEXiUpV25CN+CrqfRxJKNbNJNs7i+8c1E0n5KC6ZKG70A/br7hrUg8lnnf UcMjxhaipKDYLGNmMM2xgdjQ3njd7TD6ke56y/wksHXf4YKJU7yoY08C4d5QHvzLW1mh UMUss3/9txQDTdiKJiWreeXfIyv5YUy26zUIOC2aAcz6TIPBJwN2HjsTaXuNQisebQUI 9aboT9P82IFbEPcsghyOIk50JChCLf2YO5EAEr06t5x3noU998hTS2rO7UM0NoPIWyZE BlMA== X-Gm-Message-State: AOAM530VX4iQXBXxpQJLxURUpospZ7k5/RNhoRqGEwaw5Z6M0H5Cvsc2 6HHRjunoTCq91kAp7BE34JBZD1Mz++Zzgr4gzYZKDQ== 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" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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