From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 B2AB242E8D6 for ; Fri, 11 Sep 2026 10:19:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789121969; cv=none; b=nTECo/UZu2UwQsmO3R5P+6Zl9qt5MkHXi9KbAXvUwwUpoBhb/kDfDmBf2BDMFDEpoo4TV9gloBazfSVY45ShDyWG9bpcc+cGg+4QCcYLshcdKFbLcvWrH7zrsrn+m5SfsWzVrPiXTFrxuAJqCFbqTYwRSt7PXuSAQkoe5bieLgs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789121969; c=relaxed/simple; bh=LyM82dSPAoxD1ECL3cim9jzMpE05vcHmndgsrH4nxHE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=sce6RFNNb+qPn8MqDQF8hmBADPX3y/fbyUrPSQ0fUaWF5APuTkgsN12TbnE7koXsUbLSMQx/vfSX/wr12EvUJR9kmwOQAb++Tj75kQrNzkKSY2FpL07Nf/GwRCVZOwcyhoTM98NG4RCUQF4T02a7nUdAvOf0X7NUaU6IwKicy/Q= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bZIhiUjZ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="bZIhiUjZ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 733A61F000FF; Fri, 11 Sep 2026 10:19:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789121967; bh=RujwQAraUAFps8XFWwJ00y0IuC6HN+2wM5m56sc/vpc=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=bZIhiUjZ2l8LZMATomme7DqNaXjDz/ghJ1aOwpz4WSYdndTPuYzlna1VxFSfyUdkI HtNUV9pKo3N4HDusN07LB5Fi/JlIcO2lfMdqdBBaxoJhkNOXOiObN8jhuAQELcHNZd YulQWUjlzjBQ0CGiiKJq9mf8wIjF3om8uzetYkvyQOa4PLN/xFCFQ1+gQyiZJ5vk+l stua/1He6Ry9uDKhshPVfQwLGxklE4eOez4u0+2JmX8opNdayND5h13e5mMKsKiy5D WwBBIdJiwF+/O1LgjfxaHe/ZS7tppBNDP0nZurEeaJEZqeCTsMgMIyjAADUcpVPT4b bPOmDkbNBSjVg== Date: Fri, 11 Sep 2026 11:19:21 +0100 From: Simon Horman To: Mohsin Bashir Cc: netdev@vger.kernel.org, alexanderduyck@fb.com, kuba@kernel.org, kernel-team@meta.com, andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, mike.marciniszyn@gmail.com, lee@trager.us, jacob.e.keller@intel.com, leitao@debian.org, vadim.fedorenko@linux.dev, daskald@meta.com, bobbyeshleman@meta.com, asml.silence@gmail.com Subject: Re: [PATCH net-next] eth: fbnic: Make Rx completion coalescing configurable Message-ID: <20260911101921.GA48209@horms.kernel.org> References: <20260909211111.1795726-1-mohsin.bashr@gmail.com> 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-Disposition: inline In-Reply-To: <20260909211111.1795726-1-mohsin.bashr@gmail.com> On Wed, Sep 09, 2026 at 02:11:11PM -0700, Mohsin Bashir wrote: > From: Mohsin Bashir > > The Rx completion queue writeback coalescing window controls how long > the queue manager may defer writing completions to host memory. > > Expose this window through the standard rx-cqe-nsecs ethtool > parameter. Preserve the existing 2000 ns default and accept values > from 1000 ns through the device maximum (~109 us). > > Hardware expresses COAL_WAIT in 600 MHz core clock cycles, or 1.667 ns > per cycle. Programming rounds the configured value to the nearest clock > cycle, resulting in an error of less than 1 ns. Retain the requested > value for get_coalesce() because this error is below the one-nanosecond > resolution of the ethtool interface. > > Signed-off-by: Mohsin Bashir Reviewed-by: Simon Horman