From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from simark.ca by simark.ca with LMTP id kDGbNLd5ZmRJ3A0AWB0awg (envelope-from ) for ; Thu, 18 May 2023 15:17:11 -0400 Received: by simark.ca (Postfix, from userid 112) id D586B1E11E; Thu, 18 May 2023 15:17:11 -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=AaTkCy87; 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=-9.0 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,NICE_REPLY_A, 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)) (No client certificate requested) by simark.ca (Postfix) with ESMTPS id 93FF31E0D4 for ; Thu, 18 May 2023 15:17:11 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=lists.lttng.org; s=default; t=1684437431; bh=AZpIv7DawULSDWeW//ktltTGXptYrfsd3p+hEYa6iRw=; h=Date:To:Cc:References:In-Reply-To:Subject:List-Id: List-Unsubscribe:List-Archive:List-Post:List-Help:List-Subscribe: From:Reply-To:From; b=AaTkCy87+DAGFYhkHXKTZDnfHv2yfDUZKVvkWFR83hA+22cJ4BFKdgjWN+VyBRQeo J2603T1+YSVLbK0pXMyH+9gu66wBMGdr3UMDGjoH/Vgb/XsbX4/H3QVsUJVzc0xL2Z vbDVfbRMG/UJExedu7v2P+h8SbjXLEZWWLSIPs5g48QsGcPGDm4EVXjh4VbjTfJJvH hFmx5jz1CVLL6kBmYeWXwkWv2Uw8fo/jFHzGh/j2Q98cZm/FxgRf1Mxk78Ld7qZ0+T YiI72kI9YSLJiBFCsZWmEDJSDunqsuCwC0tBLFC3Do1/+E0bxhgn+/5DZy5+9vcZMZ Wt2GLdpV87ipA== Received: from lists-lttng01.efficios.com (localhost [IPv6:::1]) by lists.lttng.org (Postfix) with ESMTP id 4QMfqW0VHNz1Fyq; Thu, 18 May 2023 15:17:10 -0400 (EDT) Received: from smtpout.efficios.com (smtpout.efficios.com [167.114.26.122]) by lists.lttng.org (Postfix) with ESMTPS id 4QMfqT5Wbqz1Fyp for ; Thu, 18 May 2023 15:17:09 -0400 (EDT) Received: from [172.16.0.117] (192-222-143-198.qc.cable.ebox.net [192.222.143.198]) by smtpout.efficios.com (Postfix) with ESMTPSA id 4QMfpt6ggwz134x; Thu, 18 May 2023 15:16:38 -0400 (EDT) Message-ID: Date: Thu, 18 May 2023 15:16:45 -0400 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.10.0 Content-Language: en-US To: Brian Hutchinson Cc: lttng-dev@lists.lttng.org References: <2d953bd2-6544-3357-1424-fa44731e2bf5@efficios.com> <2f8ea79e-9515-854b-d3b0-707baba60b92@efficios.com> In-Reply-To: Subject: Re: [lttng-dev] Trying to understand use of lttng enable-event --kernel --userspace-probe= 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: Mathieu Desnoyers via lttng-dev Reply-To: Mathieu Desnoyers Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset="us-ascii"; Format="flowed" Errors-To: lttng-dev-bounces@lists.lttng.org Sender: "lttng-dev" On 2023-05-18 15:07, Brian Hutchinson wrote: [...] >> >> If you attach to an ELF symbol (function), then there is no USDT in >> play, so it should not be related to the issue you have. > > That is what I was thinking which is why I wanted to try it. > >> >> But if your functions happen to be inlined, then there will be nothing >> to attach to. Perhaps this is what happens there ? > > I don't see any evidence of anything being inlined in this module. I > grepped the code to verify. > > Back to being stumped/stuck. Make sure to check the resulting assembler and ELF symbol tables. The compiler is free to inline various functions unless they are explicitly marked as __attribute__((noinline)). Also, if LTO is enabled, further optimization can be done at link-time. One purpose of the UST tracepoints is to be less fragile with respect to specific optimizations done by the compiler and linker, thus guaranteeing that whatever is instrumented with a tracepoint is indeed available for tracing. Also, double-check that the path you pass to --userspace-probe really targets your executable or .so binary file, and is not just a symbolic link. Thanks, Mathieu -- Mathieu Desnoyers EfficiOS Inc. https://www.efficios.com _______________________________________________ lttng-dev mailing list lttng-dev@lists.lttng.org https://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev