From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-fw-80009.amazon.com (smtp-fw-80009.amazon.com [99.78.197.220]) (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 398DC13A89D; Thu, 15 Feb 2024 20:16:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=99.78.197.220 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708028206; cv=none; b=QnjxWdqm7IdNmf3O6/TKg9GZ13/FPZvVjN8eZQr7pRTqDdY0NZGemf9SFEoo8B0ASrPDiQItCU+6hAclDA7KKcs5NDm3uTO8SXCwKacUqiPK+lV5/4SHZlLh8wElJNxKDIZ9wn+vvW38LHjeHwTyWGuUxnbC7Zcg9de3ONr3KbA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708028206; c=relaxed/simple; bh=qEoishFH9LSRy8HKcQT4KXqD7rpsFJk2tkkb37zTSQg=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=CdhnNvI6XpXlXPt3JwczEBm4C1DCC1KLVE52fWIMkDED5/GcGw8Q1vxuFLeGDSgmFABsGBKQ96fFZbfIWz53qicrgQZrFDlm5M9gFmgdSySDd3xM3bn2bV3nefF+rF12H8Yn46JKf7ldcCJmhjyB/PABljDQH/OuRhGuvsv9tZ8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com; spf=pass smtp.mailfrom=amazon.co.jp; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b=RWejxXsq; arc=none smtp.client-ip=99.78.197.220 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=amazon.co.jp Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="RWejxXsq" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1708028205; x=1739564205; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=YBjtAKZ77n9OzAqyM18gje3GFkDj2C2xPunRe3LSwdE=; b=RWejxXsq9zUWRFHl4oHihpRhXJ39V1A90fmfOnqT/8UtLAlsykdRiu6d 1XDCXlznSjj3F/cC5XwlfkjBiqGeI/dha7SYfa2aSfnQyWzohmmxJsYBs 2g+mZqorBBJ+H3ixBW1Y3rIfoe2jTi7NsI4EJyQ4rz5I2/8gJa8vpFSaL E=; X-IronPort-AV: E=Sophos;i="6.06,162,1705363200"; d="scan'208";a="66349554" Received: from pdx4-co-svc-p1-lb2-vlan2.amazon.com (HELO smtpout.prod.us-west-2.prod.farcaster.email.amazon.dev) ([10.25.36.210]) by smtp-border-fw-80009.pdx80.corp.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Feb 2024 20:16:42 +0000 Received: from EX19MTAUWC001.ant.amazon.com [10.0.7.35:14292] by smtpin.naws.us-west-2.prod.farcaster.email.amazon.dev [10.0.60.209:2525] with esmtp (Farcaster) id 1a26d7d8-1842-4416-a8a6-b81504bdf866; Thu, 15 Feb 2024 20:16:42 +0000 (UTC) X-Farcaster-Flow-ID: 1a26d7d8-1842-4416-a8a6-b81504bdf866 Received: from EX19D004ANA001.ant.amazon.com (10.37.240.138) by EX19MTAUWC001.ant.amazon.com (10.250.64.174) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.40; Thu, 15 Feb 2024 20:16:38 +0000 Received: from 88665a182662.ant.amazon.com (10.187.170.20) by EX19D004ANA001.ant.amazon.com (10.37.240.138) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1118.40; Thu, 15 Feb 2024 20:16:34 +0000 From: Kuniyuki Iwashima To: CC: , , , , , , , , , , , , , , , Subject: Re: [PATCH v1 net-next] net: Deprecate SO_DEBUG and reclaim SOCK_DBG bit. Date: Thu, 15 Feb 2024 12:16:27 -0800 Message-ID: <20240215201627.14449-1-kuniyu@amazon.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: References: Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit X-ClientProxiedBy: EX19D035UWA002.ant.amazon.com (10.13.139.60) To EX19D004ANA001.ant.amazon.com (10.37.240.138) From: Neal Cardwell Date: Thu, 15 Feb 2024 12:57:35 -0700 > On Tue, Feb 13, 2024 at 3:32 PM Kuniyuki Iwashima wrote: > > > > Recently, commit 8e5443d2b866 ("net: remove SOCK_DEBUG leftovers") > > removed the last users of SOCK_DEBUG(), and commit b1dffcf0da22 ("net: > > remove SOCK_DEBUG macro") removed the macro. > > > > Now is the time to deprecate the oldest socket option. > > > > Signed-off-by: Kuniyuki Iwashima > > --- > > I would like to kindly implore you to please not remove the > functionality of the SO_DEBUG socket option. This socket option is a > key mechanism that the Google TCP team uses for automated testing of > Linux TCP, including BBR congestion control. > > Widely used tools like netperf allow users to enable the SO_DEBUG > socket option via the command line (-g in netperf). Then debugging > code in the kernel can use the SOCK_DBG bit to decide whether to take > special actions, such as logging debug information, which can be used > to generate graphs or assertions about correct internal behavior. For > example, the transperf network testing tool that our team open-sourced > - https://github.com/google/transperf - uses the netperf -g/SO_DEBUG > mechanism to trigger debug logging that we use for testing, > troubleshooting, analysis, and development. > > The SO_DEBUG mechanism is nice in that it works well no matter what > policy an application or benchmarking tool uses for choosing other > attributes (like port numbers) that could conceivably be used to point > out connections that should receive debug treatment. For example, most > benchmarking or production workloads will effectively end up with > random port numbers, which makes port numbers hard to use for > triggering debug treatment. > > This mechanism is very simple and battle-tested, it works well, and > IMHO it would be a tragedy to remove it. It would cause our team > meaningful headaches to replace it. Please keep the SO_DEBUG socket > option functionality as-is. :-) > > Thanks for your consideration on this! Oh that's an interesting use case! I didn't think of out-of-tree uses. Sure, I'll drop the patch. Thanks!