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 6F02517E9; Sat, 27 Jul 2024 02:38:05 +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=1722047885; cv=none; b=MwWs+Xyi5X7L3DuEdakpsppBHo9Br29BcvDZNV97xXxVIed4a72f3wmJgQpvdcOMNfx+baUYMO+JVQu23VxOPo2fzal7qK9aH7Ni8ouYXqfKylVpaWZeFxrxrwKs9/r87kB2QCIIVHsZFXigVGSZJE9oo0/jV5rGscAXTJglHRE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722047885; c=relaxed/simple; bh=eovpOsg4Kr/mIT7zpUFC8+Q4yEFsMXjxDoGqBIQ1fps=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Kawl1jRz5rWp4aAz7aA0BglXU+IuODgUpb481fqLMXj4wP0Hjbfv2MVErb42vxytzgImP+WLc+p1+S3vOJhSIHJyQ9x5AtQZYfcIN7PAjN9pYQ6lw+CY54XZvLFg0U9WjjObabJgjec9CPyZPskUr2CtSbTJ0py1JHT8L/j9HTk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=gdtcpQCW; 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="gdtcpQCW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7F807C32782; Sat, 27 Jul 2024 02:38:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1722047884; bh=eovpOsg4Kr/mIT7zpUFC8+Q4yEFsMXjxDoGqBIQ1fps=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=gdtcpQCWTkifX0Jp9dxA3GQfTXU/LvC4V/rCtRZdKIEHEuTY9EbHvBrzZDHzKrUoB 68BnafkMYeTKDpH+pcA22WRfbMsLbXgu12TYQw383gk2J08q4uiRRoaWtYYu8xcayY i1H3MZtX20gADdPI3dgeGaw4zB1Bob/GA98Trb+ziUXQCLWswwlPakZzK7hn4Qt0LQ zcKPSgjUTD4qenjI63vZL2Ow0ARUPX3IAclGOZ4EP8uzUHifO7t6BLp5EIjZ5KzT5u KI6WkBAZ1xEhunT8A1BCKBtIi+cRoYMglGY67cjlre30Y/jzGSk/ADk2Zxpg8yHbgv uHOlswA5A0Y9w== Date: Fri, 26 Jul 2024 19:38:03 -0700 From: Jakub Kicinski To: Shenwei Wang Cc: Wei Fang , "David S. Miller" , Eric Dumazet , Paolo Abeni , Clark Wang , imx@lists.linux.dev, netdev@vger.kernel.org, linux-imx@nxp.com Subject: Re: [PATCH v2 net-next] net: fec: Enable SOC specific rx-usecs coalescence default setting Message-ID: <20240726193803.20c36d7c@kernel.org> In-Reply-To: <20240726145312.297194-1-shenwei.wang@nxp.com> References: <20240726145312.297194-1-shenwei.wang@nxp.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-Transfer-Encoding: 7bit On Fri, 26 Jul 2024 09:53:12 -0500 Shenwei Wang wrote: > The current FEC driver uses a single default rx-usecs coalescence setting > across all SoCs. This approach leads to suboptimal latency on newer, high > performance SoCs such as i.MX8QM and i.MX8M. > > For example, the following are the ping result on a i.MX8QXP board: > > $ ping 192.168.0.195 > PING 192.168.0.195 (192.168.0.195) 56(84) bytes of data. > 64 bytes from 192.168.0.195: icmp_seq=1 ttl=64 time=1.32 ms > 64 bytes from 192.168.0.195: icmp_seq=2 ttl=64 time=1.31 ms > 64 bytes from 192.168.0.195: icmp_seq=3 ttl=64 time=1.33 ms > 64 bytes from 192.168.0.195: icmp_seq=4 ttl=64 time=1.33 ms > > The current default rx-usecs value of 1000us was originally optimized for > CPU-bound systems like i.MX2x and i.MX6x. However, for i.MX8 and later > generations, CPU performance is no longer a limiting factor. Consequently, > the rx-usecs value should be reduced to enhance receive latency. > > The following are the ping result with the 100us setting: > > $ ping 192.168.0.195 > PING 192.168.0.195 (192.168.0.195) 56(84) bytes of data. > 64 bytes from 192.168.0.195: icmp_seq=1 ttl=64 time=0.554 ms > 64 bytes from 192.168.0.195: icmp_seq=2 ttl=64 time=0.499 ms > 64 bytes from 192.168.0.195: icmp_seq=3 ttl=64 time=0.502 ms > 64 bytes from 192.168.0.195: icmp_seq=4 ttl=64 time=0.486 ms > > Performance testing using iperf revealed no noticeable impact on > network throughput or CPU utilization. Sounds like an optimization, net-next is still closed: https://netdev.bots.linux.dev/net-next.html Please repost after Monday. -- pw-bot: defer