From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) (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 1A3BC228C9D; Sat, 13 Dec 2025 06:40:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.12 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765608005; cv=none; b=duLBf7G9Iz63DPeYxNWQntNpLoh7kYlefGQqHMKqhluTi1BJiZg+pYiIfD/qQDzG481UYPnUAqsnEwJY42A7jZPiRK6MlvwzXJZ7f7FIY9+z93/Rn5ZcG/MJl+lNl5DYf/FJChLd9B/ugeiXHkmi6f4GpA6fcH8+PbbCVkjrG9c= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1765608005; c=relaxed/simple; bh=gb1M4S239Rk2pV8pAOHzG+Ffyav9kJa6yrKX+RMxYWE=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=HAufdEq84VG7scEiwNL1EgUQ+yV75bdiWYyFWmyJZyM+bbXEGqF1zwB7dnBbOg593vsH59L7wu31IHl6MAPRIsKDQkwSjgaN1G28GuYXWq5oUw4G7bHfZVh1I+FOZzyX5TqG2q4Cxu1EuQfU1JuWs3WHlPbveuM8x1rEv8ghSk8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org; spf=pass smtp.mailfrom=goodmis.org; arc=none smtp.client-ip=216.40.44.12 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=goodmis.org Received: from omf03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 961711404D6; Sat, 13 Dec 2025 06:20:58 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf03.hostedemail.com (Postfix) with ESMTPA id 39AA06000B; Sat, 13 Dec 2025 06:20:54 +0000 (UTC) Date: Sat, 13 Dec 2025 01:20:50 -0500 From: Steven Rostedt To: Mathieu Desnoyers Cc: "Paul E. McKenney" , Joel Fernandes , "linux-kernel@vger.kernel.org" , Sebastian Andrzej Siewior , "bpf@vger.kernel.org" , Thomas Gleixner Subject: Re: [PATCH v3] tracing: Guard __DECLARE_TRACE() use of __DO_TRACE_CALL() with SRCU-fast Message-ID: <20251213012050.576eead3@fedora> In-Reply-To: <09c76498-6a0b-4880-8a86-2a295c47c703@efficios.com> References: <0ec97a2d-5aee-4214-b387-229e9822b468@paulmck-laptop> <83cd4b4d-1eec-47d0-be91-57c915775612@paulmck-laptop> <7683319A-AB3D-4DF4-8720-9C39E3C683BA@nvidia.com> <39252902-567b-4e74-b6c4-91eae1df7c0d@paulmck-laptop> <20251212211839.6c3e2399@fedora> <09c76498-6a0b-4880-8a86-2a295c47c703@efficios.com> X-Mailer: Claws Mail 4.3.1 (GTK 3.24.51; x86_64-redhat-linux-gnu) 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=US-ASCII Content-Transfer-Encoding: 7bit X-Stat-Signature: n7qz5qdzzmnhwwfc8ir9r88gcrdijmgo X-Rspamd-Server: rspamout04 X-Rspamd-Queue-Id: 39AA06000B X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX19V07REGIYtSgIpxWl75AGch8puwtuOgxE= X-HE-Tag: 1765606854-447506 X-HE-Meta: U2FsdGVkX1+j32QEBIj90Zv4U/lD2XQyfLqcxFmK2ho22V44y2HEPw8I2nmkSve80cRQNfo/PWxisWwlQAd8WGpMylgYcLo1y8BmPDjbMDEr55WGX3Vik/3wq9uXjts4AtPZCrYLEzZaz8h2PAUE3HgMDDx86oVAAMbjWGjoYN3Bm3knIYXDj8xkT7/MRmNZRQl5puqqZjs+r8vXsGcNYBzoR8mfPpliFcVaSM2S/t43vA6btvQ03MY1S0MFwXfeJ38gnMdAxHvPcWNL70LgOb4u0lJHzJNl3bDuaVyzaKEi3p5i2ZOrRuMYBEbBOhQDcVgPz3WRjYk/5Hx/xtvzlqR9Yz74Wm2YhcrwcJBUk24pKpC6k58tDRjjVIv3iqSD On Fri, 12 Dec 2025 23:19:41 -0500 Mathieu Desnoyers wrote: > Here is one additional thing to keep in mind: although > SRCU-fast is probably quite fast (as the name implies), > last time I tried using migrate disable in a fast path > I was surprised to see verbosity of the generated assembly, > and how slow it was compared to preempt disable. > > So before using migrate disable on a fast path, at least on > non-preempt-RT configs, we should carefully consider the > performance impact of migrate disable. Right, which is another reason I'm keeping that part of the patch as-is. -- Steve