From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from simark.ca by simark.ca with LMTP id lZxVIzgoL2RG6SQAWB0awg (envelope-from ) for ; Thu, 06 Apr 2023 16:14:48 -0400 Received: by simark.ca (Postfix, from userid 112) id 856D81E221; Thu, 6 Apr 2023 16:14:48 -0400 (EDT) Authentication-Results: simark.ca; dkim=pass (2048-bit key; unprotected) header.d=lists.lttng.org header.i=@lists.lttng.org header.a=rsa-sha256 header.s=default header.b=xGZ7/gt0; dkim-atps=neutral X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on simark.ca X-Spam-Level: X-Spam-Status: No, score=-8.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.6 Received: from lists.lttng.org (lists.lttng.org [167.114.26.123]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by simark.ca (Postfix) with ESMTPS id B23851E0D3 for ; Thu, 6 Apr 2023 16:14:47 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=lists.lttng.org; s=default; t=1680812087; bh=Lw06925XhiDg7BfB2YxIjWDfbw5ZghIs7HrSD6K30P0=; h=Date:To:Subject:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:List-Subscribe:From:Reply-To:From; b=xGZ7/gt0P2oY55HwrtwVkEhsz/ggbTOqS6vPJ4K+9HS/uiN5T6nhdf6vbu5W8Ws3O xgUe52Vx7ihEz/bthL1m3BBX/QZxX20xI7N5EyOSPxy1C0PSy0QAWR1KVdpp/sT3oy rmtmRX3LY2ZwIw9h/wjd28HM/rzmRlJs7z29nCeawzu1McHAV5b1kLxXrGSJBV6E4W obdjg1i3/6UFaJGAVpnrxHKBr9Mt4HKgNtQ04N50m4WXbIed7Fq9p4Io2zJYk1c7wc DBv+TaOaR9VohPLYvkjTgAne/G7Rx+LPvAUb+Z673GmeYb7IXfemzZmScI/aONo9Tc /zDTRI+QqcC2w== Received: from lists-lttng01.efficios.com (localhost [IPv6:::1]) by lists.lttng.org (Postfix) with ESMTP id 4Pst5M031Nz2NYQ; Thu, 6 Apr 2023 16:14:47 -0400 (EDT) Received: from smtp.polymtl.ca (smtp.polymtl.ca [132.207.4.11]) by lists.lttng.org (Postfix) with ESMTPS id 4Pssjv1b2Gz2NKL for ; Thu, 6 Apr 2023 15:57:55 -0400 (EDT) Received: from horde2019.polymtl.ca (www.imp.polymtl.ca [132.207.6.45]) by smtp.polymtl.ca (8.14.7/8.14.7) with ESMTP id 336JuVEd021794 for ; Thu, 6 Apr 2023 15:56:31 -0400 DKIM-Filter: OpenDKIM Filter v2.11.0 smtp.polymtl.ca 336JuVEd021794 Received: from Sansfil-Eduroam-Etudiants-15-40.polymtl.ca (Sansfil-Eduroam-Etudiants-15-40.polymtl.ca [10.200.15.40]) by www.imp.polymtl.ca (Horde Framework) with HTTPS; Thu, 06 Apr 2023 19:56:30 +0000 Date: Thu, 06 Apr 2023 19:56:30 +0000 Message-ID: <20230406195630.Horde.jhBZfsMqxFud8S3napU7CjJ@www.imp.polymtl.ca> To: lttng-dev@lists.lttng.org User-Agent: Horde Application Framework 5 MIME-Version: 1.0 Content-Disposition: inline X-Poly-FromMTA: (www.imp.polymtl.ca [132.207.6.45]) at Thu, 6 Apr 2023 19:56:31 +0000 X-Mailman-Approved-At: Thu, 06 Apr 2023 16:14:45 -0400 Subject: [lttng-dev] Seeking Assistance on LTTng for Kubernetes Performance Research X-BeenThere: lttng-dev@lists.lttng.org X-Mailman-Version: 2.1.39 Precedence: list List-Id: LTTng development list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Benjamin Saint-Cyr via lttng-dev Reply-To: Benjamin Saint-Cyr Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed"; DelSp="Yes" Errors-To: lttng-dev-bounces@lists.lttng.org Sender: "lttng-dev" Dear LTTng Developers, I am currently conducting performance research on Kubernetes for my master's thesis and am using LTTng for data collection and Trace Compass for analysis. I have a couple of questions and concerns, and I would appreciate your guidance to ensure I am using your tools effectively. 1. In the Control Flow view, I can see the CPU throttling due to the quota defined in the Cgroup as the pod runs and then waits for the CPU periodically. However, it is unclear whether the pod is waiting due to a full CPU or because of timeshares. I can easily find this information in /sys/fs/cgroup/cpu,cpuacct/kubepods//pod/cpu.stat if the pod is being throttled. Is there a way to extract this information using LTTng or Trace Compass? 2. I am attempting to determine which PID is running a specific Container/Pod UID. Currently, I can deduce this by observing the process named runc[*:INIT], as it creates the cgroup and clones the process for the container. However, this approach is fragile and only works due to an implementation detail. It also fails if tracing starts after deployment. This information is easily available in /sys/fs/cgroup/cpu,cpuacct/kubepods//pod//cgroup.procs. Is there an existing method within LTTng to obtain this information that I may not be aware of? I have been informed that it might be possible to read the information in cpu.stat or cgroup.procs using a state dump at the beginning or end, but the process remains unclear. Alternatively, I could instrument the kernel or the process handling the accounting, but this would be quite challenging. Another option would be to use something similar to cAdvisor, but its efficiency is questionable since it dedicates an entire process to reading a few files. I would greatly appreciate any guidance or suggestions you may have on improving my approach and effectively utilizing LTTng for my research. Thank you for your time and assistance. Best regards, Benjamin Saint-Cyr _______________________________________________ lttng-dev mailing list lttng-dev@lists.lttng.org https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev