From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 9984720ED; Sun, 2 Feb 2025 03:26:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738466789; cv=none; b=M4C8aAogwm9qG+RYYTbZoCZrIGYv6yXsDUEwFpq6VEx/XvdJVHAoVG+tBLISrH8C5t17i68+Do/juUs9/YiPcEAIwZ1snbXQumg8EC4E3R5lDkqHuVMSjPQqU1udcGKsLg97zgcDmj/RciDAVUI5PTPS1CpH9rUM0AUtq7jTnV4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738466789; c=relaxed/simple; bh=EL8R7+4DLL9JYXNTxNyqGEzs87ccKluFIBrQZ9V3Fxo=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=CHdmE1hD9QyhSdA8zI/1XIDao8sgiK5IjJkI6avqbWDzNw/Nk0/YUBQDHWolSv9uJRitSppTqq9b7kIKfj/dtOngPUN5SC4uA0/vxfyQ3DKW1G2nRAXKDQ7VdMa6K8NagbOO1aHug0pz70g+qLjNOztUUMj5ZL/h1lJJwwPDsVs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 Received: by smtp.kernel.org (Postfix) with ESMTPSA id EBDB2C4CED1; Sun, 2 Feb 2025 03:26:25 +0000 (UTC) Date: Sat, 1 Feb 2025 22:26:24 -0500 From: Steven Rostedt To: Linus Torvalds Cc: Mathieu Desnoyers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Thomas Gleixner , Peter Zijlstra , Ankur Arora , linux-mm@kvack.org, x86@kernel.org, akpm@linux-foundation.org, 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@oracle.com, konrad.wilk@oracle.com, jgross@suse.com, andrew.cooper3@citrix.com, Joel Fernandes , Vineeth Pillai , Suleiman Souhlal , Ingo Molnar , Clark Williams , bigeasy@linutronix.de, daniel.wagner@suse.com, joseph.salisbury@oracle.com, broonie@gmail.com Subject: Re: [RFC][PATCH 1/2] sched: Extended scheduler time slice Message-ID: <20250201222624.61722cdb@batman.local.home> In-Reply-To: References: <20250131225837.972218232@goodmis.org> <20250131225942.365475324@goodmis.org> <20250201180810.1faf4906@batman.local.home> X-Mailer: Claws Mail 3.17.8 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Sat, 1 Feb 2025 15:35:53 -0800 Linus Torvalds wrote: > I didn't actually check what current active schedulers do. I would > not be in the least surprised if different schedulers end up having > very different behavior (particularly any RT scheduler). The only real use of sched yield() I have ever seen in practice was in a RT application where all tasks were given the same RT FIFO priority, and the application would use the yield() system call to trigger the next task. That's also the only use case that really does have a strict defined behavior for yield(). In SCHED_FIFO, as the name suggests, tasks run in a first-in first-out order. yield() will put the task at the end of that queue. You can use this method to implement a strict application defined scheduler. -- Steve.