Date: Thu, 18 Oct 2007 13:39:49 +0200 From: Alexander Leidinger <Alexander@Leidinger.net> To: John Baldwin <jhb@freebsd.org> Cc: arch@freebsd.org, "Constantine A. Murenin" <cnst@freebsd.org> Subject: Re: sensors fun.. Message-ID: <20071018133949.1430dlowvks8w4kg@webmail.leidinger.net> In-Reply-To: <200710171245.36949.jhb@freebsd.org>
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Quoting John Baldwin <jhb@freebsd.org> (from Wed, 17 Oct 2007 12:45:36 -0400): Without commenting on specific parts of what you wrote, I think we need to clarify something before we proceed. > Other things that might be nice: > > - IWBN to have a userland interface to sensors. For example, if nothing else Here's what I wrote to Julian (with minor modifications) this morning, before I've seen your mail here on arch. I see several levels of stuff which can be named "sensors framework" here. One level is in the kernel. It's just an export interface to transfer status data from the kernel to userland. The goal of this framework is IMO to "collect" all this data in the kernel and provide a single point of contact for the userland to query this in-kernel data. That's what the soc project was about. Let's call this kernel sensors framework here. Then there's something in the userland, what can also be named "sensors framework". This part would be responsible to be a single point of contact to query the status data of the entire system. This userland part would be responsible to collect data which is exported from the kernel, and to collect data from userland stuff. It would provide an interface to be able to query the in-machine data (some people may say SNMP can be used for this). Let's call this single-system sensors framework here. And then there's something in the network what can be named "sensors framework". This part would be responsible to collect sensor data in the entire (sub-)network and provide an interface to query the data from the entire (sub-)network (an example can be nagios or some commercial offering). Let's call this group-level sensors framework for now. The term "sensor data" may by ambiguous too. When I talk about sensor data, this can be some data from a device, like temperature/voltage/humidity/tv channel/ rotation speed/pressure level/fill level/coordinates/whatever (what we want to include of this stuff or not I don't talk about, e.g., ATM I don't see a need to provide the TV channel via the sensors framework). Sensor data can also be the status of a subsystem in the kernel, some database related things in userland, the hitrate per second of a webserver, or whatever. All (more or less) of those things may in the end need to arrive in the group-level sensors framework. Before they arrive there, they ideally arrive in the single-system sensors framework (reduces probing complexity and the amount of work of the person who has to configure the group-level sensors framework). And parts of this stuff was collected from the kernel sensors framework by the single-system sensors framework. The group-level sensors framework doesn't belong into FreeBSD IMO. For the single-system sensors framework I have no strong opinion (and with bsnmp we may have some sort of this already which just needs to be a little bit extend (MIBs), but this depends upon your needs and expectations). What I would like to know is where you see problems with the above description and how your proposal fits into this description (if you don't see major flaws in the description). To me it looks like your proposal spans more than one of the above described layers in one package. It seems you describe what I call single-system sensors framework above. It looks like you want to have this with parts of it in the kernel. I don't think this is a good idea as I don't think userland data should be feed into the kernel. Could you please describe where you see benefits of your architecture compared to the description I provided above? Bye, Alexander. -- BOFH excuse #266: All of the packets are empty http://www.Leidinger.net Alexander @ Leidinger.net: PGP ID = B0063FE7 http://www.FreeBSD.org netchild @ FreeBSD.org : PGP ID = 72077137home | help
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