From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id CA2EB3AE190 for ; Mon, 30 Mar 2026 08:51:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774860698; cv=none; b=uto9xLrR11R/gNrLuZj4mbRTube51KxluCMiWwop05/kSkkyDcmavgKThLHljOkpSwYhwfk9CzebgZOv1k+mul7ZHqaFrvUFVAl894lP9ysQdDz3pMkuWC7tAHRG+ixu8LTRKYjuxMBqh4n6VOEK/cfS34jDXqubmRyFUXes/oU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774860698; c=relaxed/simple; bh=DwD1DsSkIZC/Y1yrfZ4Aog/2TnNiAlz9yKJBYrkREas=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=MXEyzIwBGVb1QuhzCPU1YBYqhOrND7dF17d3EZ3HXGVeUoW1ozI7wzG7v5tFHgspw2c4GPDgq+lOw60ipygr/ZzO7f0m5mWOfkFILS25kzWe92z/QQumwQdES2hOFcn9myE5OEt28dSvp7yj9NeHZwk722Dkkl377Ynir5nnyuQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=TX6BQxm8; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="TX6BQxm8" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 16FD31C00; Mon, 30 Mar 2026 01:51:28 -0700 (PDT) Received: from [10.1.32.28] (e127648.arm.com [10.1.32.28]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id E3CA43F915; Mon, 30 Mar 2026 01:51:32 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1774860693; bh=DwD1DsSkIZC/Y1yrfZ4Aog/2TnNiAlz9yKJBYrkREas=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=TX6BQxm8cCikgdTWGKhOxxEmebbQuNGet6wEVDUVqRqj7/SMxQkZyMPm0h0c2CYYX klmKkLN8vrjQSR5IM5xU4TEyJMOGUq646ZKShdqTzJZfCLPYzu0saU2wXjTeZPcoIH 7ziho55PBCNJPZJ6MLnAnfzELtX6olXhMD/y6di0= Message-ID: <5e3191ef-32cb-44a3-90a1-66ad8327a030@arm.com> Date: Mon, 30 Mar 2026 09:51:31 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 2/2] selftests/sched_ext: Add cyclic SCX_KICK_WAIT stress test To: Tejun Heo , David Vernet , Andrea Righi , Changwoo Min Cc: Emil Tsalapatis , sched-ext@lists.linux.dev, linux-kernel@vger.kernel.org References: <20260329001856.835643-1-tj@kernel.org> <20260329001856.835643-3-tj@kernel.org> Content-Language: en-US From: Christian Loehle In-Reply-To: <20260329001856.835643-3-tj@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 3/29/26 00:18, Tejun Heo wrote: > Add a test that creates a 3-CPU kick_wait cycle (A->B->C->A). A BPF > scheduler kicks the next CPU in the ring with SCX_KICK_WAIT on every > enqueue while userspace workers generate continuous scheduling churn via > sched_yield(). Without the preceding fix, this hangs the machine within seconds. > > Signed-off-by: Tejun Heo Reviewed-by: Christian Loehle