From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from unimail.uni-dortmund.de (mx1.hrz.uni-dortmund.de [129.217.128.51]) (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 7823F3AE19C for ; Thu, 30 Apr 2026 09:45:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=129.217.128.51 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777542349; cv=none; b=eaiwQUVVVG0zeLWqBV3RJb/7aw6BPYw7ynLL7R2FnyABz7xEMF+dqCAc0r7yfvzxSJJ9AZ0ePTvs3BX7dvrLmY7ZQlrQmequ02cSERUGWpU7pPF6jWqFn5EwimkswpHK0YoF04M60P/ydi1P6jgjPiv4pIagvtdwHDnkA3VeYrY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1777542349; c=relaxed/simple; bh=QDslXe+wxXz5Sle2ZLJzuC1bnySYRgtXv3okkVLqu5g=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=U+hMABiYcOFt6IWXMQ4EoOHYlcVxqY2Kvkdfvps/Ssd1wjAhoqC4tCeYy4SEYpybk90WCFZbMsNzjEg+ZxK+bHntDrqA+37h8UiaRZEmPaFuh/UanGEv7ZSuFLaQBWOOSq9Igo7obqckdoxSkPXBJf0xRJng8Kowp8wy2aBg38E= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=tu-dortmund.de; spf=pass smtp.mailfrom=tu-dortmund.de; dkim=pass (1024-bit key) header.d=tu-dortmund.de header.i=@tu-dortmund.de header.b=aH0YYmPC; arc=none smtp.client-ip=129.217.128.51 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=tu-dortmund.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=tu-dortmund.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=tu-dortmund.de header.i=@tu-dortmund.de header.b="aH0YYmPC" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=tu-dortmund.de; s=unimail; t=1777542327; bh=QDslXe+wxXz5Sle2ZLJzuC1bnySYRgtXv3okkVLqu5g=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=aH0YYmPCsnknvGmIaOKTwAjqO0F8P7l7dCNyLzCUAqStulfZVer3U3XddZnaItI7h ZUqkhDpQkZ60eyKO1LfKRseletXxRX3PJcEF3BwM4ao6wwn1aXlplcpH9qBnuXcnEm 0KqX+FT7s5siIV3fu3zCpVnO1gy8qgieNw9abaw4= Received: from [129.217.186.229] ([129.217.186.229]) (authenticated bits=0) by unimail.uni-dortmund.de (8.18.2/8.18.2) with ESMTPSA id 63U9jEZE021677 (version=TLSv1.3 cipher=TLS_AES_256_GCM_SHA384 bits=256 verify=NOT); Thu, 30 Apr 2026 11:45:15 +0200 (CEST) Message-ID: <7bc8edc9-1b46-471a-9a6e-cd2c27aebcfc@tu-dortmund.de> Date: Thu, 30 Apr 2026 11:45:14 +0200 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net-next 5/5] selftests: net: add veth BQL stress test To: =?UTF-8?Q?Jonas_K=C3=B6ppeler?= , hawk@kernel.org Cc: andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, horms@kernel.org, jhs@mojatatu.com, jiri@resnulli.us, kernel-team@cloudflare.com, kuba@kernel.org, netdev@vger.kernel.org, pabeni@redhat.com References: <20260324174719.1224337-7-hawk@kernel.org> <02a713ac-f794-416f-9d69-95ea98d515b6@tu-dortmund.de> <1c435d90-8d08-4ac1-8b84-cc72c0b4e30f@tu-berlin.de> Content-Language: en-US From: Simon Schippers In-Reply-To: <1c435d90-8d08-4ac1-8b84-cc72c0b4e30f@tu-berlin.de> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 4/30/26 11:17, Jonas Köppeler wrote: > On 3/28/26 4:19 PM, Simon Schippers wrote: >> Hi, thanks for your work! I am really interested in this patchset. >> >> I am planning to submit a similar patch set (see [1]) for the tun/tap >> driver, where I am currently implementing qdisc backpressure similar >> to that used in veth. >> >> Can you run pktgen [2] to see if there is a regression? >> I think that there might be a slowdown due to BQL not choosing a big >> enough queue size. > I ran some tests using pktgen by replacing the trafficgen from the > selftest with samples/pktgen/pktgen_sample01_simple.sh (Patch v3) > and used --nrules 0. In general the throughput is quite similar: > > BQL disabled (using --bql-disable): > 2378694pps 1141Mb/sec (1141773120bps) errors: 0 > 2400898pps 1152Mb/sec (1152431040bps) errors: 0 > 2358125pps 1131Mb/sec (1131900000bps) errors: 0 > 2402034pps 1152Mb/sec (1152976320bps) errors: 0 > 2362061pps 1133Mb/sec (1133789280bps) errors: 0 > 2416301pps 1159Mb/sec (1159824480bps) errors: 0 > 2398496pps 1151Mb/sec (1151278080bps) errors: 0 > 2415200pps 1159Mb/sec (1159296000bps) errors: 0 > 2375921pps 1140Mb/sec (1140442080bps) errors: 0 > 2427419pps 1165Mb/sec (1165161120bps) errors: 0 > 2382461pps 1143Mb/sec (1143581280bps) errors: 0 > > mean: 2392510pps > > BQL enabled: > 2159545pps 1036Mb/sec (1036581600bps) errors: 0 > 2321899pps 1114Mb/sec (1114511520bps) errors: 0 > 2477853pps 1189Mb/sec (1189369440bps) errors: 0 > 2447857pps 1174Mb/sec (1174971360bps) errors: 0 > 2400284pps 1152Mb/sec (1152136320bps) errors: 0 > 2442841pps 1172Mb/sec (1172563680bps) errors: 0 > 2442540pps 1172Mb/sec (1172419200bps) errors: 0 > 2410585pps 1157Mb/sec (1157080800bps) errors: 0 > 2395902pps 1150Mb/sec (1150032960bps) errors: 0 > 2393260pps 1148Mb/sec (1148764800bps) errors: 0 > 2401959pps 1152Mb/sec (1152940320bps) errors: 0 > > mean: 2390411pps > > BQL enabled is ~2099pps (~0.09%) lower than BQL disabled. Sounds great! One more thing: Could you check what BQL limit settles during the test run using something like: watch -n 0.1 'cat /sys/class/net/XXXXX/queues/tx-0/byte_queue_limits/limit' I guess it will just choose the ptr_ring size as limit in this case, but it would be nice if you could briefly verify this :) Thanks! > >> Thanks! >> >> [1] Link:https://lore.kernel.org/all/20260312130639.138988-1-simon.schippers@tu-dortmund.de/ >> [2] Link:https://www.kernel.org/doc/html/latest/networking/pktgen.html