From owner-freebsd-dtrace@freebsd.org Mon Jan 2 21:54:31 2017 Return-Path: Delivered-To: freebsd-dtrace@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 1C14CC9C466 for ; Mon, 2 Jan 2017 21:54:31 +0000 (UTC) (envelope-from markjdb@gmail.com) Received: from mail-qk0-x22c.google.com (mail-qk0-x22c.google.com [IPv6:2607:f8b0:400d:c09::22c]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id BF3901E03 for ; Mon, 2 Jan 2017 21:54:30 +0000 (UTC) (envelope-from markjdb@gmail.com) Received: by mail-qk0-x22c.google.com with SMTP id t184so360221084qkd.0 for ; Mon, 02 Jan 2017 13:54:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=8aEjlqO7opmsR/Saxk8A+8zWIzlt9BlXxBAL1+MQOiU=; b=mIrMxK6jvyibv+TyUGsO4TqFlZnvxR/xK7TKeUqftmEGtz2sU7VZcQ9aZ/McWnU16i Tmq9IubUiPneibFG9Z3RyOxbsqecJM/36i+w6NEHUqhBkUnoF/dGsUCs4/nuJhI3DIzh 7B+0FYK9nrQCzr8I5HIBl1oA884U2WRxpQ5kTZvqNAUsKQVpUIb5rXcPAolDZcfcq0PN 4AqKs/JWSLW28BdJw+y9us+n2W7MPz6V4g39b4DO4wx3nV31DJxX78oWvfXCiB6XrlK8 l0OTqCwRWh927id6ak2a3nALbJxXAYkfJI1tql4fMWRcJW3jmBEx92cZGgi14KiJh6M4 xwpg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=8aEjlqO7opmsR/Saxk8A+8zWIzlt9BlXxBAL1+MQOiU=; b=rv4+M3iakx0rMdGbzopfmoB6EzR0qvLqV+lGawwnMl/bmQlQ18osXc3+NGy2GH17NB 7FmONuF/wAcw1s8JlK1g6ZhT4fBmRuozZEctmpajONLfF9HHDCPF/UJ6haJjb+jy3KoR fLyBrwCIGvIhVnP8YANuScl0ZalcjJDRiIAwmr9WmJ1QXpl6nFtot/cWt194uowgJf7i kQiDsCUt2Ih6Hzoi/7UN5u5eEebUhFQa5VHBsUbWvp18/QmLkN2qZuD6wJHCZxnnTgpT yrJfZQ/OcjN2YVeZo2ORdZeSBUTh1zHU2wsNSORbW+aIisvD8vceBu12ELMSKaYyrYtN 0p2A== X-Gm-Message-State: AIkVDXIgY69RWTYc4+63Y7ycLCaM+GfS1zofOpyMeSYzMZhQtNWsBHT0bfa1Eif7ZfFYIQ== X-Received: by 10.55.190.66 with SMTP id o63mr58283826qkf.254.1483394069965; Mon, 02 Jan 2017 13:54:29 -0800 (PST) Received: from wkstn-mjohnston.west.isilon.com (c-76-104-201-218.hsd1.wa.comcast.net. [76.104.201.218]) by smtp.gmail.com with ESMTPSA id p19sm42300231qtp.4.2017.01.02.13.54.28 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 02 Jan 2017 13:54:29 -0800 (PST) Sender: Mark Johnston Date: Mon, 2 Jan 2017 14:00:29 -0800 From: Mark Johnston To: Domagoj Stolfa Cc: freebsd-dtrace@freebsd.org Subject: Re: RFC: Changes in DTrace to allow for distributed operation Message-ID: <20170102220029.GC46812@wkstn-mjohnston.west.isilon.com> References: <20161230173747.GB46006@freebsd-laptop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161230173747.GB46006@freebsd-laptop> User-Agent: Mutt/1.7.2 (2016-11-26) X-BeenThere: freebsd-dtrace@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "A discussion list for developers working on DTrace in FreeBSD." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 02 Jan 2017 21:54:31 -0000 On Fri, Dec 30, 2016 at 06:37:47PM +0100, Domagoj Stolfa wrote: > Hello, > > I have been working on extending DTrace to allow for a natural way of tracing in > a distributed environment. This would consist of being able to trace events on > different virtual machines, remote servers with access, cluster nodes and so on. > I will summarize the changes I have made and have thought of making, outly all > the design tradeoffs, flaws and merits of each design tradeoff I have thought of > making in hopes of getting feedback from others interested in distributed > tracing. I think some concrete examples of what you'd like to be able to accomplish with this would help a lot. Is the goal here to be able to trace multiple independent systems at once and somehow aggregate their trace records? That's what "distributed tracing" suggests to me, but from reading your email it seems as though you're primarily interested in some form of remote tracing whereby one could execute something like # dtrace -n 'fbt$guest::kern_ioctl:entry' on a hypervisor and get records (in real time?) from a guest. Assuming I'm not completely off-base, this is a cool idea, but I think your objective needs to be more clearly defined before it's possible to evaluate the merits of different designs, especially when you're proposing adding new concepts to the core DTrace code.