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 E5EC81DE3C4 for ; Fri, 13 Dec 2024 11:54:42 +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=1734090883; cv=none; b=nSSiAtaBO27Qwy7d1PordxJ19jH7HUOJP1EHABb21NJzjQ5MNRGwPLDuPff1+0yDfxvFvY+lYn03zrXVKv+pOtzW3ZLnn7FHiygD/y6M0WFv4AXQgeZfEOWGKWZJHs4RqY7HY7kLsDH//nqimen7BCbxlNiX2QTabrswSql+gvY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734090883; c=relaxed/simple; bh=nEQGTQHmIQhO0/A9uStQC/R0spmJDZztIzVtIEjRsyk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=IaOF6y0eLRFlP2j2ZYHaXcRv0PYBVGGtKbflIfDXmnZhwsuMQS4ZOLduetY1A4BafV+PlfP58CaL14fSuNGBD3sK54xXZ+Z+L/IGlno1FTIgib2vQhqpx90Os/I1ZfVaVZtVvlOoQJovkg3UB/7oUl56GVrnirfk9fhAPdesDWA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ESq6JEwk; 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="ESq6JEwk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BE190C4CED0; Fri, 13 Dec 2024 11:54:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1734090882; bh=nEQGTQHmIQhO0/A9uStQC/R0spmJDZztIzVtIEjRsyk=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ESq6JEwktjriu1cljx3tf9sSHX+DDhg+Qm0bpw3zow1aJBEt9S/PWnlnint+AwgJG q8EI0fw4oTVEGvLMGAkjP2H7LwmMALFLMolYlZGeuopTmtaypJCBNt8jM7eTuj56Ih Ufs+Y8krPM6aSK8wSiRBkGmIHZpRFDCZfSfUC4q26wHfm3t+UTpzdQPci3i0pVmESZ EdW4G6baxNiCi+smBSpGKfhrUFKuAMtk6HHwAvp9UsEtVal7xTWKeHiM/zUF2TLuP4 xJK9Ml6ZhO8pcA1YA3pBlWMTtrLuBDD1wmtjUiOxxmVIeQuJTw39JK7orudUwBHiwr QZcFzfEn5R34w== Date: Fri, 13 Dec 2024 11:54:38 +0000 From: Simon Horman To: Michal Schmidt Cc: intel-wired-lan@lists.osuosl.org, netdev@vger.kernel.org, Arkadiusz Kubalewski , Karol Kolacinski , Przemek Kitszel , Tony Nguyen , Miroslav Lichvar Subject: Re: [PATCH iwl-next 2/3] ice: lower the latency of GNSS reads Message-ID: <20241213115438.GP2110@kernel.org> References: <20241212153417.165919-1-mschmidt@redhat.com> <20241212153417.165919-3-mschmidt@redhat.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: <20241212153417.165919-3-mschmidt@redhat.com> On Thu, Dec 12, 2024 at 04:34:16PM +0100, Michal Schmidt wrote: > The E810 is connected to the u-blox GNSS module over I2C. The ice driver > periodically (every ~20ms) sends AdminQ commands to poll the u-blox for > available data. Most of the time, there's no data. When the u-blox > finally responds that data is available, usually it's around 800 bytes. > It can be more or less, depending on how many NMEA messages were > configured using ubxtool. ice then proceeds to read all the data. > AdminQ and I2C are slow. The reading is performed in chunks of 15 bytes. > ice reads all of the data before passing it to the kernel GNSS subsystem > and onwards to userspace. > > Improve the NMEA message receiving latency. Pass each 15-bytes chunk to > userspace as soon as it's received. > > Tested-by: Miroslav Lichvar > Signed-off-by: Michal Schmidt Reviewed-by: Simon Horman