From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793984391; b=JSIziN4Is0IgsrsAlI3FO7ZrXWKdqRDpG9jBb6WOp8gliGXqmzl1u/K0lz+IgyiWrhjV 6fxzrvz5WrRxA+xQvcLfn1g6aTSPauJMw5btRXWkXvuy/oRxgxL+4LPpiJuDLkl5dMD4p KpDlyWNXNtghICkpPKNc9cxga3Ai9jjJswV/lzonTeTtjCCEvjB+I8pYDZRBPh4uWL/Fw LITRpbI8qH2f9jlQzUQ9XvnU3MZf949VzBPS6He/L0hNT6PE5y/JOnJXrLfu8BHVIWGPp DDM+EdSYi22R4dSv2Ibomz9j4pBxvZL87Gk6uZu4OhdGhicFykALtWCLCvtPjX+PjLw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793984391; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-ID: References:MIME-Version:Content-Type:Content-Disposition:In-Reply-To; bh=KL+KSSXu3b8P5TKRa9ZgiayGp/Utp/dI5DQ/LmoYroo=; b=IdU1M9tKmShKYmiau9mOkMcsPbGfpAhCw6yjSgLjUHq4SdGX5UEgTO5ewobddBBSisST YzwDBM6eQhih13f7kA6oulrgSGToJjTHxr0XNlCkNy5WVQRPcvR65NScJg0VEiKCpLOaD GiiZNCB+Qu+2TlB5vvTUWyU3pzJp937TEPw82uzAmTTG7hvkiCZucoO0QwzRvNuh9Ctul 8T1CL3IR/H+r1pD24rlWOZTGftPQfoRbAmOX9oe1+/42ulPaQY+mE2kMe8PN2UUQzsxNq JZhYDsuU1SejUpC7sKWv2odXqQqZPkc1GNsEhyAsijSSfpYx1+YsncVTFbe+IIUJA2A== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=XwIuSmBm; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 549DF606A335; Fri, 6 Nov 2026 16:59:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=XwIuSmBm Received: by smtp.kernel.org (Postfix) with ESMTPSA id D3AB11F008A2; Fri, 6 Nov 2026 16:59:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1793984391; bh=KL+KSSXu3b8P5TKRa9ZgiayGp/Utp/dI5DQ/LmoYroo=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=XwIuSmBmUiVCt4kN66UhGgrBG/oCgNdFJ6a+vDduteFCLQknDwuTd5vT06d1a0JJy SozeFV0CdkNSN79W7i5pdU12xifwDBz1ra6pN/MHJs0hJ67PYQ/q9BEDCWx+qEsu9u oYinMpVm+Q6nd71HytqI8seX78PE3dFBgAlTTcyxn/t+EaOuIQZfW3G2cHEm2LTme9 x4MARZcpBaU+4kC5ujG0k1gWL845TJ4Gmgxw8CQqt5gcrj0qXzG+ZfSlmHiqNd3RE/ BHFcknoq8ADyKHUGHryvc2drY4Cda3wDUFARr8OBUMnio+03YoGHz6q1MmrmeDELDM LmtpHi9Ou/KYQ== Date: Fri, 6 Nov 2026 06:59:50 -1000 From: Tejun Heo To: Radu Toader Cc: peterz@infradead.org, mingo@redhat.com, tglx@kernel.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de, vschneid@redhat.com, kprateek.nayak@amd.com, void@manifault.com, arighi@nvidia.com, changwoo@igalia.com, frederic@kernel.org, anna-maria@linutronix.de, bigeasy@linutronix.de, joshdon@google.com, haoluo@google.com, brho@google.com, linux-kernel@vger.kernel.org, sched-ext@lists.linux.dev, bpf@vger.kernel.org Subject: Re: [PATCH 1/2] sched_ext: Add scx_tickbug, a scheduler that holds a task on an idle CPU Message-ID: References: <20261106094343.174905-1-radu.m.toader@gmail.com> <20261106094343.174905-2-radu.m.toader@gmail.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261106094343.174905-2-radu.m.toader@gmail.com> Hello, On Fri, Nov 06, 2026 at 09:43:42AM +0000, Radu Toader wrote: ... > This scheduler is the same thing with the kick removed: a tagged task > is parked on the target CPU's run queue and released only by a timer > pinned to another CPU, so the window is as wide as -H says. Untagged > tasks go through a shared DSQ and per-CPU kthreads keep their local DSQ > and preemption, so the machine stays usable and the timer's softirq > cannot be starved. Thanks for catching the bug. However, this scheduler is more of an one-off debug code and I'm not sure we want to carry this in tree. Maybe put it in a github gist or sth and point to it from the fix patch? Thanks. -- tejun