From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (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 325555339F for ; Wed, 11 Sep 2024 09:13:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.92.199 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726046025; cv=none; b=WJh/slRBtP1qX8ALrVZ4YYPO8WpAFWFZTN8HV4eXv9MQtAU24m02AQrg8djR0hqXzY1+2Fewtiz9sgsCiIqpcOMIEdlHZW0Uthl048eS2Xeqor4fSu6UHk+L0JtOJR0YZhTs0bqghu6diSueVm/iZeLBsV7jN4aWsJMkQUoqiKs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726046025; c=relaxed/simple; bh=+TPij8FfGpoiqOZVfxF7YnF6MD7c4NnCFj3YmqLJpRo=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=OHkwmtKKgHeEmpDaHKpe+0+9ak4N/TEyv95RaNP83QErCl6BRHzSGGbmPn+QQHLPDnhSVs0K5SPffpwxlfLOJMA8L66vuVSEHPw6olojKS3QX8Vmt8lJ1pB8p/Cldr7nNfzLS2Im0qWWes8AyIOwbPktW0tG/LovgZPxxOE+rk4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=mj4abAQJ; arc=none smtp.client-ip=90.155.92.199 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="mj4abAQJ" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=desiato.20200630; h=In-Reply-To:Content-Transfer-Encoding: Content-Type:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Sender:Reply-To:Content-ID:Content-Description; bh=34o6bTM0ZyPEB27rus1S/oT82gPMUgCCbVenuFYnt/c=; b=mj4abAQJXkdF+lR7gclmvb96me AUmBwIv8nLgNzWL3hv7LTebQCoELGemqfTudQ0Swv9BAvHDXJfcVRApLXe5M1FpNaNqYR8rlbP326 gzECLfhSIKqyi8+v8FUyKVhdZGTiy3gHq6RJ6QWQstD6iHNkARuVTWvhoobp03W1Pb4GYatlDNAKJ JNq/ZWFkPoC7UOylMTtOjgecSs4KY8J7nUsLGOg4V1J+PYQ0vSCcWEICl/6OpffRpO2WiZbv/buRt w7g/e46MRSwtZVF3FS0/WhzIkgkwHmgVU5neqntrHIxrEEPVEKIffSZaz4tYpPu2nouc9iku+gYa7 Abq3ZEnw==; Received: from j130084.upc-j.chello.nl ([24.132.130.84] helo=noisy.programming.kicks-ass.net) by desiato.infradead.org with esmtpsa (Exim 4.98 #2 (Red Hat Linux)) id 1soJPk-00000000963-1jev; Wed, 11 Sep 2024 09:13:28 +0000 Received: by noisy.programming.kicks-ass.net (Postfix, from userid 1000) id 1095B300642; Wed, 11 Sep 2024 11:13:28 +0200 (CEST) Date: Wed, 11 Sep 2024 11:13:28 +0200 From: Peter Zijlstra To: Mike Galbraith Cc: Luis Machado , Dietmar Eggemann , Vincent Guittot , Hongyan Xia , mingo@redhat.com, juri.lelli@redhat.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, linux-kernel@vger.kernel.org, kprateek.nayak@amd.com, wuyun.abel@bytedance.com, youssefesmat@chromium.org, tglx@linutronix.de Subject: Re: [PATCH 10/24] sched/uclamg: Handle delayed dequeue Message-ID: <20240911091328.GM4723@noisy.programming.kicks-ass.net> References: <20240905145354.GP4723@noisy.programming.kicks-ass.net> <20240906104525.GG4928@noisy.programming.kicks-ass.net> <8d0d01b9-a430-49cc-93a5-67b4d68aa35c@arm.com> <20240910140524.GH4723@noisy.programming.kicks-ass.net> <52ca4cea-8f65-434e-af17-e4bf664d9488@arm.com> <20240911084528.GJ4723@noisy.programming.kicks-ass.net> <4fde8f26a9aeaeafda15b81bbb17b0ffc96941f0.camel@gmx.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <4fde8f26a9aeaeafda15b81bbb17b0ffc96941f0.camel@gmx.de> On Wed, Sep 11, 2024 at 11:10:26AM +0200, Mike Galbraith wrote: > On Wed, 2024-09-11 at 10:45 +0200, Peter Zijlstra wrote: > > On Wed, Sep 11, 2024 at 09:35:16AM +0100, Luis Machado wrote: > > > > > > > > I'm assuming that removing the usage sites restores function? > > > > > > It does restore function if we remove the usage. > > > > > > From an initial look: > > > > > > cat /sys/kernel/debug/sched/debug | grep -i delay                                                                                                                                                                                                                             > > >   .h_nr_delayed                  : -4 > > >   .h_nr_delayed                  : -6 > > >   .h_nr_delayed                  : -1 > > >   .h_nr_delayed                  : -6 > > >   .h_nr_delayed                  : -1 > > >   .h_nr_delayed                  : -1 > > >   .h_nr_delayed                  : -5 > > >   .h_nr_delayed                  : -6 > > > > > > So probably an unexpected decrement or lack of an increment somewhere. > > > > Yeah, that's buggered. Ok, I'll go rebase sched/core and take this patch > > out. I'll see if I can reproduce that. > > Hm, would be interesting to know how the heck he's triggering that. > > My x86_64 box refuses to produce any such artifacts with anything I've > tossed at it, including full LTP with enterprise RT and !RT configs, > both in master and my local SLE15-SP7 branch. Hohum. Yeah, my hackbench runs also didn't show that. Perhaps something funny with cgroups. I didn't test cgroup bandwidth for exanple.