From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail.tipi-net.de (mail.tipi-net.de [194.13.80.246]) (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 C081D3E5578; Mon, 15 Jun 2026 11:44:23 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=194.13.80.246 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781523867; cv=none; b=CZwcBlL+GxB/RxRwSyvPxek8ppcpMrETis5m3/J4dHNaxA1VoRZqeQJtVslrx4Nn/K6VKzUmJxrpUQu8NUEI0xEh1XjHiDAD/nc0OlYnlgK5em1+T08WwjixYrlOSdCuPIqsxE1dOZl710IIosN1tJHX5ZotbNDjqZ0vGKNy0gE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781523867; c=relaxed/simple; bh=QzEQ8bmQRcac/cdT+HGYuruEQVR11ZuItIOQrzpOmVk=; h=MIME-Version:Date:From:To:Cc:Subject:In-Reply-To:References: Message-ID:Content-Type; b=UJPCeDPFPg1v8MdXLVG61jjDLYWGDUVuFLrMZ3bwmsA7VPQTtmdvmq3Z3EpWOPi11FxQhSfoXb0y5bQFIKkBhf1zLaVXxaGQb6YRLeA71woupFKZbAZLzciLXLCEyr2znaRtwu5HWbQM3YY3WRGjqY1LntCrkaH5+yzM9pciplg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=tipi-net.de; spf=pass smtp.mailfrom=tipi-net.de; dkim=pass (2048-bit key) header.d=tipi-net.de header.i=@tipi-net.de header.b=n4eepFDb; arc=none smtp.client-ip=194.13.80.246 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=tipi-net.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=tipi-net.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=tipi-net.de header.i=@tipi-net.de header.b="n4eepFDb" Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 3E6E2A4B51; Mon, 15 Jun 2026 13:35:57 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tipi-net.de; s=dkim; t=1781523360; h=from:subject:date:message-id:to:cc:mime-version:content-type: content-transfer-encoding:in-reply-to:references; bh=vcQo2gA7ahzyNWTX7sbWOasW0OaO/03aDK6BDJtgCBk=; b=n4eepFDbySOqpEaPs8y8xch/b32ovHXoy6YC2tV9ekCiWvfOekjgnSr4rEwqVfIvDp5Ana /IRJCL9kQIJrHbxs0K4ChL6KMN4pvhbddP+4GcfIIR11WbDIt0O34YKY8T1I8fPhUWcJHZ zEIBA6dtw+3C0wTCSj5yECmORAI97gQn47kzkmdI0RRTi01oZgMaAX4kcqpCkGBPJiBRDV NM/Crds8cV+K7wncHQ9II3yAEGIJyz9v4vS6bvg3dTki58dWDN+yZBm8dQFYTYcaoBTjuZ XFTt/f/Vut7ZfzrwWMWHsblKTYWEzbNv4bZWo4/oxH51hcl7/Ea2BNf7aDG2Qg== Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Date: Mon, 15 Jun 2026 13:35:57 +0200 From: Nicolai Buchwitz To: Jakub Kicinski Cc: Doug Berger , Florian Fainelli , bcm-kernel-feedback-list@broadcom.com, Andrew Lunn , "David S . Miller" , Eric Dumazet , Paolo Abeni , Justin Chen , Ovidiu Panait , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net-next 0/3] net: bcmgenet: collapse TX priority queues In-Reply-To: <20260613145745.36c5403e@kernel.org> References: <20260612205915.3156127-1-nb@tipi-net.de> <20260613145745.36c5403e@kernel.org> Message-ID: <59249267ef946bb39b647fb9cc816c98@tipi-net.de> X-Sender: nb@tipi-net.de Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit X-Last-TLS-Session-Version: TLSv1.3 Hi Jakub On 13.6.2026 23:57, Jakub Kicinski wrote: > On Fri, 12 Jun 2026 22:59:12 +0200 Nicolai Buchwitz wrote: >> Tested on Raspberry Pi CM4 (BCM2711): >> - Ovidiu's reproducer (iperf3 -u -b0 -P16 -t60) no longer trips >> NETDEV_WATCHDOG. >> - UDP sustains 956 Mbit/s line rate over 60 s with 0 datagrams >> lost (0/4952890). >> - Single-stream TCP throughput unchanged at 943 Mbit/s. > > Of course it has no impact on a single TCP stream test, since TCP > stream can only use one queue. If anything it should help. > The testing here is not very convincing. At least install a realistic > qdisc (fq/fq_codel/cake) and run multi-stream test with multiple cores? > What's the CPU idle delta in such a test? Fair. Tests I ran with fq_codel: # TCP iperf3 -c -P 16 # UDP iperf3 -c -u -b 1000M -P 16 # RR iperf3 -c -t 60 & netperf -H -t TCP_RR -l 30 -- -r 1,1 With the following results (all based on net-next with PP): PP PP+WRR PP+series TCP -P16 Mbit/s 938 941 941 TCP retransmits 56228 57679 48606 UDP -b1000M -P16 Mbit/s 956 956 956 TCP_RR under TCP load 451.7 453.8 596.8 CPU idle 91.55% 90.53% 90.97% CPU0 softirq 32.6% 33.4% 33.5% CPU1-3 idle (avg) 97.6% 97.7% 97.7% So WRR fixes the watchdog issue, otherwise is within noise. This series adds ~31% TCP_RR under load and reduces retransmits by ~14%. Note, that bcmgenet on BCM2711 has only two IRQs and no per-queue affinity, so all HW interrupts are handled by one core regardless of queue count. > > The reason for this change is not coming thru from the submission. > Ovidiu's patch makes much more intuitive sense. I'll apply that, > please rebase. Will rebase and resend with a hopefully better reasoning :) Thanks Nicolai