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=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 12933C43603 for ; Wed, 11 Dec 2019 20:38:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D3B02206A5 for ; Wed, 11 Dec 2019 20:38:43 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="KBDqTVad" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728117AbfLKUin (ORCPT ); Wed, 11 Dec 2019 15:38:43 -0500 Received: from mail-io1-f68.google.com ([209.85.166.68]:41650 "EHLO mail-io1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726242AbfLKUim (ORCPT ); Wed, 11 Dec 2019 15:38:42 -0500 Received: by mail-io1-f68.google.com with SMTP id c16so217541ioo.8; Wed, 11 Dec 2019 12:38:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=js6RVN7j31/GZRIwpW6XAyIVVSgpszrUnhZR4AgZ4yE=; b=KBDqTVadjplSXvCM2S86+WTP7Y7TWI4QaZi2Y4hiulMVCDpjFy525FnKsnhC+tQHMn Qm89vJPIv7ua7tN1LSb51wRo6CpgCF/t12v3sZ9BhA/vGvvLWBxHHLugbd+o74h+ZSCM 3EWNEF2ZQZdjHGbN1IlHwH3QilNyMFTTAbt23QQkrRt9DBlMdSeXn1kQqVQGmcCpA2p7 11a+grgG/AJJO6RqVQwQcqqJxFGBc6dq+OgShyn1m2k5Vwdf6y+nkch0GW2ryOK09KH1 TGEALHLhPn/D+VNY5qH09UA4EGO1I9MuNe4cPSsq2QXwuZC/1DJ7Fi8yYnDLscDk72mi blGQ== 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=js6RVN7j31/GZRIwpW6XAyIVVSgpszrUnhZR4AgZ4yE=; b=JBVpMF7CeEoOz/x/nJ0aXHx1rBjKNZCjcUwEYiZDJdPRoKxQbdLNqRiVjpANaWb+74 +CIyeYodWBq21WSs6Cp+dqyXoZ5/kh9Ng8tTFMpSG+uEHuieyvKRPC4VI85fxsKlAShD CVAjyZLVB1J3notnuzb5/+qvUbZwqWVhZzLBlsbJv6fbUNVzb9xOaCP34giwdvcFBBfI BD91g7OcTRSoeGi1GJvFyjrULX+UOya1BQd2pQ6QDICM1TKfhnFRvs9PSnZYkIDuQhOT r8EHt56IpbXb8dg68zfvDzHIGhrtQ7dhI7WfFUiZXd7mNBNpy3L2HHFeKW9fMGALaYUN C/AA== X-Gm-Message-State: APjAAAWFEonEAfFi6leChRIvfAQfhx5l6hOLSfGtKsFMpwvrUHUD5B+0 7TvHo+NJTHx0sPbD7XO//vrZbl/iOKd7J+UuftI= X-Google-Smtp-Source: APXvYqwQeKbO/dYcrquPZ+NylZ+Iftd8dHKvUxFqZqGzmOWsz4cA0DN70p2YTHWuQO/mWHyZO8fVIy8IS6BiN6x2r48= X-Received: by 2002:a05:6638:a2c:: with SMTP id 12mr4977856jao.60.1576096721721; Wed, 11 Dec 2019 12:38:41 -0800 (PST) MIME-Version: 1.0 References: <20191112012724.250792-1-dima@arista.com> <20191121180555.GA440967@gmail.com> In-Reply-To: <20191121180555.GA440967@gmail.com> From: Dmitry Safonov <0x7f454c46@gmail.com> Date: Wed, 11 Dec 2019 20:38:30 +0000 Message-ID: Subject: Re: [PATCHv8 00/34] kernel: Introduce Time Namespace To: Thomas Gleixner , Andy Lutomirski , Ingo Molnar Cc: Dmitry Safonov , Andrei Vagin , open list , Adrian Reber , Andrei Vagin , Arnd Bergmann , Christian Brauner , Cyrill Gorcunov , "Eric W. Biederman" , "H. Peter Anvin" , Jann Horn , Jeff Dike , Oleg Nesterov , Pavel Emelyanov , Shuah Khan , Vincenzo Frascino , Linux Containers , crml , Linux API , X86 ML Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Gentle ping, in case you have time to look at this. On Thu, 21 Nov 2019 at 18:05, Andrei Vagin wrote: > > Hi Thomas, > > What is your plan on this series? We know you are probably busy with > the next merge window. We just want to check that this is still in your > TODO list. > > On Tue, Nov 12, 2019 at 01:26:49AM +0000, Dmitry Safonov wrote: > > > > v7..v8 Changes: > > * Fix compile-time errors: > > - on architectures without the support of time namespaces. > > - when CONFIG_POSIX_TIMERS isn't set. > > * Added checks in selftests for CONFIG_POSIX_TIMERS. > > * Inline do_hres and do_coarse. > > (And added Tested-by Vincenzo - thanks!) > > * Make TIME_NS depends on GENERIC_VDSO_TIME_NS and set it per-arch. > > > > [v1..v7 Changelogs is at the very bottom here] > > > > Our performance measurements show that the price of VDSO's clock_gettime() > > in a child time namespace is about 8% with a hot CPU cache and about 90% > > Here is a typo. The price of VDSO's clock_gettime() in a child time > namespace is about 12% with a cold CPU cache. The table with > measurements for a cold CPU cache contains correct data. > > > with a cold CPU cache. There is no performance regression for host > > processes outside time namespace on those tests. > > > > .... > > > > > Cold CPU cache (lesser tsc per cycle - the better): > > > > | before | CONFIG_TIME_NS=n | host | inside timens > > -------------------------------------------------------------- > > tsc | 476 | 480 | 487 | 531 > > stdev(tsc) | 0.6 | 1.3 | 4.3 | 5.7 > > diff (%) | 100 | 100.9 | 102 | 112 > > Thanks, Dmitry