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 3168FCDB474 for ; Fri, 20 Oct 2023 14:11:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1377519AbjJTOLw (ORCPT ); Fri, 20 Oct 2023 10:11:52 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41268 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1377419AbjJTOLv (ORCPT ); Fri, 20 Oct 2023 10:11:51 -0400 Received: from mout.gmx.net (mout.gmx.net [212.227.15.15]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 456F893 for ; Fri, 20 Oct 2023 07:11:49 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gmx.de; s=s31663417; t=1697811104; x=1698415904; i=efault@gmx.de; bh=nmczSBI2pFFgwL6eKCEn0u5bcuiQ7coKuKAHrXHH3Ag=; h=X-UI-Sender-Class:Subject:From:To:Cc:Date:In-Reply-To: References; b=XaVa51oGSBG0Qi/rS2iki0S1wle/NMdW7bV6ApC85XZCtq2OXZ7kC4RSPSZ6DECd OorcViNzE/cmd3pmTtiL+PIJkHvPGxjjYIlR7RlncMUPAQBkM2LXOJ7rUr6fqmbdc TdWs2pUptCzCfokxiLW98bnXrxKYMGVkVxiYF5IzlNt5k0MvvM+BUpc0fhHY+xwzF BCtlsesqiPLHu5DgOmjLMJkO+ys4N3NEQoLjgw1bHAed6zR/+LkPjHLh/dYfrzXgu ARW05SLnBKyjQL7XslQGyJp8LTDf0F57RBxNAyW88HUD68DttW+enFkP3Vk1VBN92 LATD52cMPvUuI6eTdg== X-UI-Sender-Class: 724b4f7f-cbec-4199-ad4e-598c01a50d3a Received: from homer.fritz.box ([185.221.149.246]) by mail.gmx.net (mrgmx005 [212.227.17.190]) with ESMTPSA (Nemesis) id 1MYvcA-1qyMTo0H0i-00UoPd; Fri, 20 Oct 2023 16:11:44 +0200 Message-ID: Subject: Re: Runtime overhead of PREEMPT_DYNAMIC From: Mike Galbraith To: Emanuele Rocca Cc: linux-kernel@vger.kernel.org, Michal Hocko Date: Fri, 20 Oct 2023 16:11:43 +0200 In-Reply-To: References: <7a818250a8f36476f13b57a172fdb1ab23645edc.camel@gmx.de> Content-Type: text/plain; charset="UTF-8" User-Agent: Evolution 3.42.4 MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Provags-ID: V03:K1:Ya0oBRzIObLGOe+BtNukTIBsIM22KAKK56AC/28STBvj5o0sjAH kU7ZByjiaZs/uj0B485f5CLBFDUuvlwLertcIyx9tLOrEwYwYvROBnWqfRYKOY9abnPqubH vXvFaaWWr4ceUEb1+rvLdN36fhxhZVI8liw06134hJFEKQzn4MSZ5OODvxj/8srvod9KDzU cFctldGHKElu9ujrJ/K8Q== UI-OutboundReport: notjunk:1;M01:P0:PG8iyFXqxXY=;1rorWEGKij9QHcZ1P/dWlS8eYH5 BhtDg68wCtjWS8PugD7f1tfba+wqoAT86C+hf8lV0hhhelHvQz44jil4cL6NbE8Ic7eJqRDpx HuixhhthHTg5Q0g2rH8pzxSkFvSdLmfCPJfx8pElILNiwmRpDdvKhN07zNCvFc6QbiQVhXWLY tahOzBekeqOyr3Ijwc+nEyDm0IvazvDjc5TKH6iwZVbUCm70XKA+hurmX9I0E7BVerQtFltBl nfc8Df9iMe9xh1ccl2zLZfAPoVnpYZW9ZDYSQcTR3Zu64WUdVPb2k+1Eji6Qg9tdqgc9AHCGL ETcM1kIa7e7ZhQucd6+yp7Mjof/JHQMMMbNR9a/DKCwzIFkOINVmuA3ElvadtGWBeGqe//lPL Yr+K/4HagPXtw6BSGfXkqluzVUp9hbHDGY0+QgMJ42fdPgEIIRVjMDm8ZGSGZJF5RFdoRTO3l wbAFszmI/9+hUjXahxwNs/15g5DEBmNQhHLl+MCce441VOmdIc9H8MsBn/SN+i8bQMteQxYBX zjul5UkoKZ9Fy4y72ASaMK3bQ9m/fjpBABobWCRuk0sv2mTH8+8tb5+QS+Ee+6fV1FKDcbvqh ficDPpx6sd23kcCfBkEytLtxwSowbx11RzcbcQyQBy1J3X7CLp3sx2/jM1tsFTWOMa8xMbUyv zM7PKZuVpNRG218T8Ty0t6UJ5Ck9/2wDeMmaNxFRSIfGJdvdS+xAXV9YiiG09PQmswdX5kd1J I2IUdbtXhVpNs1zkS2OdMTZVZR0+VoLeHKlAYoACTCbv4Ong8azMgJlmLvY3rPI3Q6e8plZfG 3lk1E5J7k6s2zMpvgDgtX+Or7ZJh2Yk91emkCTHRawvsO0/j02HaF/65Jqlq6sBicKFR31Mir CxaPcE6g9O8XQezPRVDew49co7YBo9+MfTcZUnlnDAIlJBgYWrm/FPwGWlNISFH1WJFoAXwA7 pBKz75AoBKwSFo5aJ1QhDgO4TYE= Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2023-10-20 at 15:40 +0200, Emanuele Rocca wrote: > Hi Mike, > > Here is the full diff between the kernel configurations I used. The only > change I made was setting CONFIG_PREEMPT_DYNAMIC=3Dn, everything else wa= s > a consequence of that AFAICT, but please do let me know if you see > anything that shouldn't be there. > > --- config-6.5.0-0.preempt-dynamic-amd64=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0= =C2=A0=C2=A0=C2=A02023-10-11 15:30:02.000000000 +0200 > +++ config-6.5.0-0.a.test-amd64=C2=A02023-10-11 14:30:02.000000000 +0200 > > @@ -10597,7 +10596,6 @@ > =C2=A0# end of Scheduler Debugging > =C2=A0 > =C2=A0# CONFIG_DEBUG_TIMEKEEPING is not set > -CONFIG_DEBUG_PREEMPT=3Dy > =C2=A0 > =C2=A0# > =C2=A0# Lock Debugging (spinlocks, mutexes, etc...) Seems you had also turned on DEBUG_PREEMPT in the dynamic setup, which adds some overhead.. but not a metric ton. -Mike