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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B3659C87FD2 for ; Thu, 7 Aug 2025 07:55:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:MIME-Version: Content-Transfer-Encoding:Content-Type:References:In-Reply-To:Date:CC:To:From :Subject:Message-ID:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=lDPf6gw3HXzny6ECXcfcEcO/+p36JpddaMwOtqXSszA=; b=owSB3xtO9Sn6QfQ7A59jE+El32 FozXZKxx9G/1sU3JUq6LU6/tK1ZpN2xz5qaSyqWDVdqhGrHLEBL2wg97pf4xP6Vb7TQlJBAdeID0k iu1Sxizlcn3lnAl/DmqTcYMJu+Y9N2v2xk7eyfWGNf0VyKyYz9OJgp4EXLSfIHsOu4C0O2nGj2AmC R0msdQzp0gS4E49KX0jLlNvpSWfJLV+Cx9F7YjlnWlDoj5osYe8p7g35lr8X/tomlso1NSYYsjfRe Z+QfVK4jmXlrMnVNa5FuCYovfPythA/E/lYUlJ2wmJz+cjMnNfSCka6fzaA4ZHbNKOLENdqJhplvu l8NIcFQA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98.2 #2 (Red Hat Linux)) id 1ujvT2-0000000HWQh-2A2Y; Thu, 07 Aug 2025 07:55:16 +0000 Received: from mailgw02.mediatek.com ([216.200.240.185]) by bombadil.infradead.org with esmtps (Exim 4.98.2 #2 (Red Hat Linux)) id 1ujvQQ-0000000HVzZ-1HIS; Thu, 07 Aug 2025 07:52:35 +0000 X-UUID: 7604e36a736311f09eb0dd999d3936bf-20250807 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=mediatek.com; s=dk; h=MIME-Version:Content-Transfer-Encoding:Content-Type:References:In-Reply-To:Date:CC:To:From:Subject:Message-ID; bh=lDPf6gw3HXzny6ECXcfcEcO/+p36JpddaMwOtqXSszA=; b=ddpZ5xXinw6yjqAAJBZkOiaPdkxiNGneBOJ5xzf08Odw6xbPk+y68wXnxAvDxQGs2HkizCq+Y81CYANcNUO3P9oSMnnF7QA2Ihcm2ayAcIHqsK/KpOre3UkiIFYz9hWCkvkfcRjxvTX9/dRsPq1XmGDLOq+MpeW7a/fNGJii48c=; X-CID-P-RULE: Release_Ham X-CID-O-INFO: VERSION:1.3.3,REQID:65e44c44-2769-4b8a-b7cb-ffbee277d53c,IP:0,UR L:0,TC:0,Content:0,EDM:0,RT:0,SF:0,FILE:0,BULK:0,RULE:Release_Ham,ACTION:r elease,TS:0 X-CID-META: VersionHash:f1326cf,CLOUDID:c0a529ce-1ac4-40cd-97d9-e8f32bab97d5,B ulkID:nil,BulkQuantity:0,Recheck:0,SF:80|81|82|83|102,TC:-5,Content:0|15|5 0,EDM:-3,IP:nil,URL:0,File:nil,RT:nil,Bulk:nil,QS:nil,BEC:nil,COL:0,OSI:0, OSA:0,AV:0,LES:1,SPR:NO,DKR:0,DKP:0,BRR:0,BRE:0,ARC:0 X-CID-BVR: 2,SSN|SDN X-CID-BAS: 2,SSN|SDN,0,_ X-CID-FACTOR: TF_CID_SPAM_SNR X-CID-RHF: D41D8CD98F00B204E9800998ECF8427E X-UUID: 7604e36a736311f09eb0dd999d3936bf-20250807 Received: from mtkmbs10n1.mediatek.inc [(172.21.101.34)] by mailgw02.mediatek.com (envelope-from ) (musrelay.mediatek.com ESMTP with TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384 256/256) with ESMTP id 1656311445; Thu, 07 Aug 2025 00:52:26 -0700 Received: from mtkmbs13n1.mediatek.inc (172.21.101.193) by MTKMBS14N1.mediatek.inc (172.21.101.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1258.39; Thu, 7 Aug 2025 15:52:23 +0800 Received: from [10.233.130.16] (10.233.130.16) by mtkmbs13n1.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.2.1258.39 via Frontend Transport; Thu, 7 Aug 2025 15:52:23 +0800 Message-ID: <9f91f77e5f39857aa84373fe1ae504de2a881533.camel@mediatek.com> Subject: Re: [PATCH] sched/deadline: Add DL server activated message From: Kuyo Chang To: Juri Lelli CC: Ingo Molnar , Peter Zijlstra , Vincent Guittot , Dietmar Eggemann , Steven Rostedt , "Ben Segall" , Mel Gorman , "Valentin Schneider" , Matthias Brugger , AngeloGioacchino Del Regno , , , Date: Thu, 7 Aug 2025 15:52:23 +0800 In-Reply-To: References: <20250805155347.1693676-1-kuyo.chang@mediatek.com> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.52.3-0ubuntu1 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250807_005234_354594_BEA9873C X-CRM114-Status: GOOD ( 24.90 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Thu, 2025-08-07 at 08:15 +0100, Juri Lelli wrote: >=20 > External email : Please do not click links or open attachments until > you have verified the sender or the content. >=20 >=20 > Hi, >=20 > On 05/08/25 23:53, Kuyo Chang wrote: > > From: kuyo chang > >=20 > > The DL server is introduced as a replacement for realtime > > throttling. > > When RT throttling is activated, a message > > "sched: RT throttling activated" is shown. However, it is currently > > difficult for users to know when the DL server is activated. > >=20 > > This patch adds a similar message to indicate when the DL server > > is activated, which helps users debug RT/CFS contention issues. > >=20 > > Signed-off-by: kuyo chang > > --- > > =C2=A0kernel/sched/deadline.c | 3 +++ > > =C2=A01 file changed, 3 insertions(+) > >=20 > > diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c > > index e2d51f4306b3..8e0de6cdb980 100644 > > --- a/kernel/sched/deadline.c > > +++ b/kernel/sched/deadline.c > > @@ -2042,6 +2042,9 @@ enqueue_dl_entity(struct sched_dl_entity > > *dl_se, int flags) > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 } > >=20 > > =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 __enqueue_dl_entity(dl_se); > > + > > +=C2=A0=C2=A0=C2=A0=C2=A0 if (dl_server(dl_se)) > > +=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2=A0=C2= =A0 printk_deferred_once("sched: dl_server activated\n"); > > =C2=A0} >=20 > Not sure if we want/need this, but, if we do, I believe > fair_server_pick_task() might be a better place to put it, as it's > really when the dl-server is called to do its job. >=20 Thanks for your suggestion, maybe the minor patch as below diff --git a/kernel/sched/deadline.c b/kernel/sched/deadline.c index e2d51f4306b3..82d1091e56f5 100644 --- a/kernel/sched/deadline.c +++ b/kernel/sched/deadline.c @@ -2395,6 +2395,7 @@ static struct task_struct *__pick_task_dl(struct rq *rq) goto again; } rq->dl_server =3D dl_se; + printk_deferred_once("sched: dl_server activated\n"); } else { p =3D dl_task_of(dl_se); } --=20 I believe the debug message could help to verify that the DL server is actually working. It will be a great help for users to debug RT/FAIR contention issues when this clue message occurs. > Thanks, > Juri >=20