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 65ABE29CE9 for ; Tue, 5 Mar 2024 03:30:35 +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=1709609435; cv=none; b=lUoCt7iV9Wp8DT5QCwSHIvs2iOHmQwsOeE8A+rgl/2NtLDejqTzC0uO+tS7QE6OJ8uJcxiPr4ktX/ukosZHFkBZXzpNkwEUCn1ueyoNHcil4hjx0i5HmeIMF1cez8Pqxy0/EZqipAbmJGNI1W8IIECUTTSNAae8c13Ii/dkdhlk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1709609435; c=relaxed/simple; bh=Dq/B4ljB9H3GcsJ/1gKLhGkQjtIFUj74G/DiDDZrpuM=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=kY0dtoyBYB9RzWC+lqTLK7DnK2UGNsFPqdfysTsmSCKIWhpOWCPDK4r+eRS4+2yGFdDYFghcDYipICIdpoIzsJNxpQcqEfobi4MUHc69/Y6OnG/jXkttdneZd1F9g2EhRKfLpDP57nFcfrAWjDBZtF45jRP8IiXAW5XjKMXWhVU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=tnySXayk; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="tnySXayk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 8607EC433C7; Tue, 5 Mar 2024 03:30:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1709609435; bh=Dq/B4ljB9H3GcsJ/1gKLhGkQjtIFUj74G/DiDDZrpuM=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=tnySXaykffJTUD3hAOyXeU84hvJY/t/lcszYnRCWWBJ/nSXRHZQaZZvuFV/G/C87P TcxGVw8uvHCe6eQUH8PU2AqGd/iZRV3BfEvwK54qZetwcAqkmv/XAEt/iBmajooJZ2 OdqUSeP29nAXrsAUp/ROxIU1UGN1TdZRD6eZG6PqHwDnbuz2Dcjuz2yxeH4jy8YOMd xwzTe2OOUWuLYjP6d20F8Kkkv0xtO962vSPzJnyEgyutu7YNu5MdpE1S4av7ttvyG3 +n34cupnm/PdVMIHl5BauSjB9XXZX+Il5MrBX+WfASzE2cjWTwQt2DlHvt8A3vdsBe x8VfcT0HBYysw== Date: Mon, 4 Mar 2024 19:30:33 -0800 From: Jakub Kicinski To: Sebastian Andrzej Siewior Cc: netdev@vger.kernel.org, "David S. Miller" , Eric Dumazet , Jesper Dangaard Brouer , Paolo Abeni , Thomas Gleixner , Wander Lairson Costa , Yan Zhai Subject: Re: [PATCH v3 net-next 0/3] net: Provide SMP threads for backlog NAPI Message-ID: <20240304193033.1c433585@kernel.org> In-Reply-To: <20240228121000.526645-1-bigeasy@linutronix.de> References: <20240228121000.526645-1-bigeasy@linutronix.de> Precedence: bulk X-Mailing-List: netdev@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 Wed, 28 Feb 2024 13:05:47 +0100 Sebastian Andrzej Siewior wrote: > The RPS code and "deferred skb free" both send IPI/ function call > to a remote CPU in which a softirq is raised. This leads to a warning on > PREEMPT_RT because raising softiqrs from function call led to undesired > behaviour in the past. I had duct tape in RT for the "deferred skb free" > and Wander Lairson Costa reported the RPS case. > > This series only provides support for SMP threads for backlog NAPI, I > did not attach a patch to make it default and remove the IPI related > code to avoid confusion. I can post it for reference it asked. > > The RedHat performance team was so kind to provide some testing here. > The series (with the IPI code removed) has been tested and no regression > vs without the series has been found. For testing iperf3 was used on 25G > interface, provided by mlx5, ix40e or ice driver and RPS was enabled. I > can provide the individual test results if needed. Acked-by: Jakub Kicinski