From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 753CEA0032; Wed, 17 Aug 2022 17:15:07 +0200 (CEST) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 3FDCA4068E; Wed, 17 Aug 2022 17:15:07 +0200 (CEST) Received: from mail-lj1-f181.google.com (mail-lj1-f181.google.com [209.85.208.181]) by mails.dpdk.org (Postfix) with ESMTP id 35DE3410E7 for ; Wed, 17 Aug 2022 17:15:06 +0200 (CEST) Received: by mail-lj1-f181.google.com with SMTP id l21so13868426ljj.2 for ; Wed, 17 Aug 2022 08:15:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:from:to:cc; bh=I0PnMtE91uTlqi3HzURFR4ULA7HULI5BTsnrnf76UAM=; b=WxnWh1AbAZ4cOU8hLiSYpKJw6VRmXrlqJQB3a4TTb0tpRB7GUZJFxm3PJS48P/RvUQ uXOXbPhN8Jqxr1pDuwWxMGCclNMwTMtp7yPpXnVKnnEDk8PmahO2dphl7nuZN8CDReaP Imw0dZYwfMbP7wXryb0eceV8xQLvl7iNJhiJC2wJo2Bt/MGSU2RQW0GeFannE4hlaUp2 sFwP4JqCQ2BkEQ2bXb3ogRFtKbkY6MJ7JG6l5YUT+iNkSyWDX/I3v+SsRq7Bz9HnK7D8 AEpmgKLR5OcAC/ph8yespOF30hr+rjgKT1jzWCvhFfBH4pNCiv6npZ7ikXp0WF0MuEgy XRWg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-message-state:from:to:cc; bh=I0PnMtE91uTlqi3HzURFR4ULA7HULI5BTsnrnf76UAM=; b=zzIGaea49pd1byLLJa+W7ZrCRtSMVUqdV2XxzgtWmcHmUuzlxh1y+jN33NN8Xu9RwC 0SOxU2jmjIHzZLlaLurmJPcUDK8lhazriwJxDXaLXdOdO/dj/Qg2B4YLc7/dD3unzcY4 jsHif3NrZfnEYR2GljPYnBTtjGldtzRraPEz/J25oqeQouVlly6egXF0pO2RWlSSDgah nhrKXdAKgDyv9kXMQ9+SaDKzhVwvfIO5q8xkrwmUE2pNyCq0l79b+gUwySrSZE7TUMiS O2peqFF8+xFjvMC0amsML5vy4GKHNkY/JEF07AUQ5kseiBOkfNFkiWVKdBzWfBJDJldX FrxA== X-Gm-Message-State: ACgBeo2u4pcQ4+vDfC1t6Tp3aK8mUUKn+D9ksWJsQWqai71Rissxqrns tFre04qnlDPxYyFwZHM6CJ8GhM8sQ2c= X-Google-Smtp-Source: AA6agR5UdLz8ZWLtMWR1rfIQOeXH64vyG+/BH205pVqTRG4P0T+Ca+qqJGLURPEdaz6AKVthlUtNqQ== X-Received: by 2002:a2e:92c4:0:b0:25d:9d30:5d61 with SMTP id k4-20020a2e92c4000000b0025d9d305d61mr8494767ljh.202.1660749305543; Wed, 17 Aug 2022 08:15:05 -0700 (PDT) Received: from sovereign (broadband-37-110-65-23.ip.moscow.rt.ru. [37.110.65.23]) by smtp.gmail.com with ESMTPSA id s2-20020a056512202200b0048ae8e4cebdsm1720609lfs.139.2022.08.17.08.15.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 17 Aug 2022 08:15:04 -0700 (PDT) Date: Wed, 17 Aug 2022 18:15:03 +0300 From: Dmitry Kozlyuk To: Stephen Hemminger Cc: dev@dpdk.org Subject: Re: [RFC] Dynamic log/trace control via telemetry Message-ID: <20220817181503.323b6230@sovereign> In-Reply-To: <20220816190837.40c557bb@hermes.local> References: <20220816021738.5498f802@sovereign> <20220816190837.40c557bb@hermes.local> X-Mailer: Claws Mail 3.18.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org 2022-08-16 19:08 (UTC-0700), Stephen Hemminger: > Not sure if turning telemetry into a do all control api makes sense. I'm sure it doesn't, for "do all". Controlling diagnostic collection and output, however, is directly related to the telemetry purpose. > This seems like a different API. > Also, the default would have to be disabled for application safety reasons. This feature would be for collecting additional info in case the collection was not planned and a restart is not desired. If it is disabled by default, it is likely to be off when it's needed. Let's consider how exactly can safety be compromised. 1. Securing telemetry socket access is out of scope for DPDK, that is, any successful access is considered trusted. 2. Even read-only telemetry still comes at cost, for example, memory telemetry takes a global lock that blocks all allocations, so affecting the app performance is already possible. 3. Important logs and traces enabled at startup may be disabled dynamically. If it's an issue, the API can refuse to disable them. 4. Bogus logs may flood the output and slow down the app. Bogus traces can exhaust disk space. Logs should be monitored automatically, so flooding is just an annoyance. Disk space can have a quota. Since the user is trusted (item 1), even if they do it by mistake, they can quickly correct themselves using the same API.