From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailgw02.mediatek.com (unknown [210.61.82.184]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2DB541DF258 for ; Thu, 7 Aug 2025 07:52:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=210.61.82.184 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754553154; cv=none; b=LkzVf/KXTXdqM67cH5eRhgCz++ckOdlG92sgPXo/6QJYvfpzPZHOgOTh0fzTrjvWR/PCMV6P5k7eg+/ZNhKAiaHWhpgPVFbqDoM6gKnSHaxSK43YpXf5m7K4byPBnJ4Hy/p+nyZyJAkoCLgpDbGVuwMSEtW3xzSPcJZudGDyNDE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1754553154; c=relaxed/simple; bh=iU6+k605Pa6dK82vz9U+wSphvD1rr/weBJyGt8qTYck=; h=Message-ID:Subject:From:To:CC:Date:In-Reply-To:References: Content-Type:MIME-Version; b=mMsGPUpGnNFSQqMsGzW3QXIRwioNJ/CO3oiM1HwbnYDyeiD1L5QEuU4b3gno1fMrGlEurwODLltobYdT2EDm5w8YqqZkgxOL0m6o6YGoDoGYmE4asBkLFd7uHXkLcHUYdAzusUNHCyuk5lUaAG/7ZVLUIzRLbBYygXI3aFQ/ows= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=mediatek.com; spf=pass smtp.mailfrom=mediatek.com; dkim=pass (1024-bit key) header.d=mediatek.com header.i=@mediatek.com header.b=ddpZ5xXi; arc=none smtp.client-ip=210.61.82.184 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=mediatek.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=mediatek.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=mediatek.com header.i=@mediatek.com header.b="ddpZ5xXi" X-UUID: 7499c072736311f0b33aeb1e7f16c2b6-20250807 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:5a43bcd2-7f06-406c-9df2-b8511d72d3bf,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:fed62fa1-1800-4e4f-b665-a3d622db32cf,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: 7499c072736311f0b33aeb1e7f16c2b6-20250807 Received: from mtkmbs14n2.mediatek.inc [(172.21.101.76)] by mailgw02.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-GCM-SHA384 256/256) with ESMTP id 445442348; Thu, 07 Aug 2025 15:52:24 +0800 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 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 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