From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 17AC71EA7F6; Thu, 6 Feb 2025 13:53:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738850038; cv=none; b=o6dfU7E6dG/Ju+S7ifLhpql/aRCHdg8AvhkWduGwvXMz1O7HyQ8QrKeRMfTqgznNB3CjfFo1zNj3KGcP+NbicF9AcQa12UYEbghMgOPi6f0vYPs8mPwXBF5BxF5ZVF1c1tdm0EyLqhO2jRXzd9/ciJRr+Bv6QT0OT0EKDanV5Vc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738850038; c=relaxed/simple; bh=RIg4iOaqEgFYPkW2inMxoFeA8rI0uIk8n+pQO4qC1J0=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=al0TJ6dm7064NT/pg3ZYA2GahPm7ae2Qcl9frLV8NNyuBk7pHYUxlmZiVhEXadlcA7hnAEPk2lp9YKKYbw/wLkrMZbu415yUzW/3SLRBPyKprKBXz8f1YrwNTPwbrSI5vA8futDTizF34Eegzbul8eT9bhmC36n8doGL8kNenbo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=pzwTHOiw; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=iTyIeh7N; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="pzwTHOiw"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="iTyIeh7N" Date: Thu, 6 Feb 2025 14:53:53 +0100 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1738850035; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=5OhWPAu4aphIzD7xlFqULoTdQ1d9FLpBhL4JzORAtrE=; b=pzwTHOiw0eZL5YDmeqk51vz9SLKgEg85QZWTqMPS1jHY0dwDmSWRFIl4awVJf1+3JTqD1c EGbeNjBzmXsaL/ZBpZkb85ozSbbD0JPbF4NwdRakdpHOeDrP8LImCCi1Uqvieo15WRkXVJ UioM7O2jzD6wS8TQx+k5r4O46ML0VN+lhZZ8lV/Qg84z5w0HE0fSYIVmCHODc9fmmdwRF4 cW/8zakoTdOfZTue0x0Paz0+yDG1C/rUfQJkcUR+UXEpuezhP6gyKk0YiotiWEdSdUpJn7 9QyXU6SJX7aYAQ8rIuNt0Mf5/s2b4pXAMvUHzxsn2SVw/Q9Ic0QJlCdfgu7CEg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1738850035; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=5OhWPAu4aphIzD7xlFqULoTdQ1d9FLpBhL4JzORAtrE=; b=iTyIeh7Njzn/4TjYMIJNO4dZZ06HQrrqMMFtJMLkWxziMGXg5Pcp1QHiud1ezdWMm5fhIE oUSv4/bv/q0c5iDw== From: Sebastian Andrzej Siewior To: Peter Zijlstra Cc: Steven Rostedt , Joel Fernandes , Prakash Sangappa , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Thomas Gleixner , Ankur Arora , Linus Torvalds , linux-mm@kvack.org, x86@kernel.org, Andrew Morton , luto@kernel.org, bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com, juri.lelli@redhat.com, vincent.guittot@linaro.org, willy@infradead.org, mgorman@suse.de, jon.grimm@amd.com, bharata@amd.com, raghavendra.kt@amd.com, Boris Ostrovsky , Konrad Wilk , jgross@suse.com, Andrew.Cooper3@citrix.com, Vineeth Pillai , Suleiman Souhlal , Ingo Molnar , Mathieu Desnoyers , Clark Williams , daniel.wagner@suse.com, Joseph Salisbury , broonie@gmail.com Subject: Re: [RFC][PATCH 1/2] sched: Extended scheduler time slice Message-ID: <20250206135353.i1tp4vDv@linutronix.de> References: <9DA1FAE6-A008-4785-BDF9-541457E29807@joelfernandes.org> <20250204220418.35949317@gandalf.local.home> <20250205081635.397eacb0@gandalf.local.home> <20250206083039.0916ad24@gandalf.local.home> <20250206134408.lD_POjuG@linutronix.de> <20250206134859.GP7145@noisy.programming.kicks-ass.net> 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=utf-8 Content-Disposition: inline In-Reply-To: <20250206134859.GP7145@noisy.programming.kicks-ass.net> On 2025-02-06 14:48:59 [+0100], Peter Zijlstra wrote: > On Thu, Feb 06, 2025 at 02:44:08PM +0100, Sebastian Andrzej Siewior wrote: > > SCHED_OTHER vs SCHED_OTHER after all. But please don't delay a wakeup of > > SCHED_FIFO/ RR/ DL because of this LAZY hint. > > Thing will get delayed if interrupts are disabled or kernel has > preemption disabled too. So as long as we ensure hint crap is of equal > order, nothing cares if you do. > > If you can't tell the difference between task does hint crap in > userspace and task is in the middle of syscall, you can't tell the > difference. I can tell the difference if I see a trace where an interrupt fires, performs a wakeup and the SCHED_OTHER task remains on CPU while the task SCHED_FIFO task sits on the runqueue until a timer fires. Sebastian