From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo2-f38.google.com (mail-oo2-f38.google.com [74.125.231.166]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0EADA33A6F1 for ; Thu, 1 Oct 2026 23:34:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.231.166 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790897646; cv=none; b=ptHQjzC8mN2PpYUQ3i0l6AvT89vWiEj/vXhqlmY0pXJPv48R/zLz4c9ri2AQLOObhflsySaJQJO43/HLaV5ORCWgUN+RWqyjtmf4/IZnDtTStTzzvS6Qz8L43S0C79F6O3plECa7QrKL90A+c8Hci5aEJ/8ofQptmC/Jov36lxw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790897646; c=relaxed/simple; bh=5ECVtE0WiBYLfGFk+kpWXr/4i8mDtbhUhuO2MP6x2LI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=obiUo0rKLNnRWydf3yY8s7X1DXl97b0na+4ozTZmiF/4T6DCpLt0lrafwwCGf34B9ncfsZ3+9wdd72EnxT1GT1ob9LzS2pzrfzku8RnSHZH+xla5BUSBeb0zlTHDU0bDL0bftloVxa8Vujd2cbms6eGFJfeBzokU2IG6NFtg6FM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=openai.com; spf=pass smtp.mailfrom=openai.com; dkim=pass (1024-bit key) header.d=openai.com header.i=@openai.com header.b=FAFlAwcp; arc=none smtp.client-ip=74.125.231.166 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=openai.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=openai.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=openai.com header.i=@openai.com header.b="FAFlAwcp" Received: by mail-oo2-f38.google.com with SMTP id 46e09a7af769-80a18990c76so4539958a34.2 for ; Thu, 01 Oct 2026 16:34:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=openai.com; s=google; t=1790897644; x=1791502444; darn=vger.kernel.org; h=content-transfer-encoding:content-type:mime-version:references :in-reply-to:message-id:date:subject:cc:to:from:from:to:cc:subject :date:message-id:reply-to:content-type; bh=5ECVtE0WiBYLfGFk+kpWXr/4i8mDtbhUhuO2MP6x2LI=; b=FAFlAwcpCIE32KmG15bPV6djIiD1G9NKzmYT6NfYF0IUiv+XSbpJjUp1822V0UasA3 omc4hfWG7IqC3PyEkjXm2Rzjp2TN1sI9ZGjaUrbvH2c3Szrs71BcW5RufOWdDXZAyTPo CyWjciMMmcXVyhYwU2RZTfrrfcl8t3jVoqQ8g= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1790897644; x=1791502444; h=content-transfer-encoding:content-type:mime-version:references :in-reply-to:message-id:date:subject:cc:to:from:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=5ECVtE0WiBYLfGFk+kpWXr/4i8mDtbhUhuO2MP6x2LI=; b=JcOnGIUVIq8fBnHJZiEd4xj9YOAthfm7h1yKZxphuLAGXZuvXTE7OyaCNNrW4kN0Ih WXqnx7NwW0CjrOhG8V1fmIQFWXMu6hwsp33J6rUoRpixKujc2gI+iyyOSoJmB1P8VEn7 Hf+EZErIoL3LWTLOk8YHAD/bqBBKaayt3G7rJc24KlfPCvTX5qbOzZkcbBeBGD2/JWnm ejUbdRm+4/9xQFvBVi00gFJEGpevhhkR40Kaz4qjTEJXbOD9lwMmhPy4TpcfBXQMHK+z fXt5TMRPuVRBK8xngpm6WmSCADQ7qDqrdwMPoc4IC4MNX4RArO7neQK17jOTiN1yMA0l +Vgw== X-Forwarded-Encrypted: i=1; AKwUvBzGcIwqqLxYtkUUG1qFxQ36puGuT0Lvq1Q9wztJ9aAZmqRRxRQQ1xnE3/ElOtAYrXtuZPdYcbA=@vger.kernel.org X-Gm-Message-State: AFuF++nPq4bUoHoMtr4serCdRFtp4tO1WFRcm2Pu468NGnGiy8E82gA8 f/nHpUZf4ws+XP38CIxumLypym0afrPW/bMHG6y84XBRUfFIg6Co08NxNjuRaXGnQvXco19n2Sg pXDYCoUM= X-Gm-Gg: AYBFou0ZMDFPv2kkCbZCo5Xq1lCMukPB7Jv3CXk+DA+1OcBumfqm4IwhRGZRbPuXOT6 eERK+Vd8dY1YjXW9tU2ytqtvbdulqgqTNaOae8Tb1dwgMqDz3YeYc10eNkTn6FLA33HiJXPoYac 74kWF/JjxxuAM7/0WlSOiFTodmFw0enRRtu+/HB3/P8wODIagMedMgPMToCdX6228C3JC5c/L84 kWtOLTVhokJIod4PZG4nBBT7/UHVyxSnwK0xidL7G3bm4ISkozn4axuOfQMTBwDgtrg5DSIBZT7 YTDLDbMWyzS8oEU5txRWuKRGv6L/s0K97zCPKQNVZhnrUFlcsB2do0724xGAeOHwJ+XTrgklVXx WfgYGKo/EkOe5tgLz4iSD9qLkQhnte7ucHM0CijWNuuM5gBSejIcoyjGAzGYMRqf3zyYlElvJLA hCgobDVVc/ZieG3/60TItYXqUgtw7sDoqNgLUH8YeizMGrrRSCuN/GL54xDvevrqSthOIPZawbQ DmrXTDvNQkX6UVs4erZktRmnEzERUeqpPQ19qbpEvw6+t+cm0kUhNSQD4QjlJ/Qr7pCrcrwZGbX Lt8= X-Received: by 2002:a05:6808:1a06:b0:4e7:3fd7:2752 with SMTP id 5614622812f47-4f52b1a630emr589736b6e.54.1790897643831; Thu, 01 Oct 2026 16:34:03 -0700 (PDT) Received: from com-68297.corp.openai.org ([199.47.143.7]) by smtp.gmail.com with ESMTPSA id 5614622812f47-4f5243d47absm687513b6e.8.2026.10.01.16.34.02 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Thu, 01 Oct 2026 16:34:03 -0700 (PDT) From: nramaswamy@openai.com To: Jakub Kicinski Cc: Neil Ramaswamy , netdev@vger.kernel.org Subject: Re: [PATCH net 1/2] tcp: restore RACK list membership when undoing loss Date: Thu, 1 Oct 2026 16:33:50 -0700 Message-ID: <20261001233352.75988-2-nramaswamy@openai.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20261001160720.0a663ec7@kernel.org> References: <20260926002520.42955-4-nramaswamy@openai.com> <20260926002520.42955-5-nramaswamy@openai.com> <20261001160720.0a663ec7@kernel.org> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Neil Ramaswamy On Thu, 1 Oct 2026 16:07:20 -0700, Jakub Kicinski wrote: > Could you add to the commit msg if this was found with an LLM scan > of the source code or its been seen in prod? Yes, I can add that to the commit message once review settles. My investigation started from seeing repeated TCP stalls in prod and the mitigation that seemed to prevent these stalls was limiting SO_SNDBUF to 96 KiB. It also seems like others have seen similar symptoms before [1] but I can't definitively say it's the same root cause. [1] https://lore.kernel.org/netdev/35A4DDAA-7E8D-43CB-A1F5-D1E46A4ED42E@gmail.com/