>>> On Wed, Dec 5, 2007 at 3:48 PM, in message <[EMAIL PROTECTED]>, Matthias Blankenhaus <[EMAIL PROTECTED]> wrote: > Hi Brad ! > > Nice meeting you yesterday :-) > > I took a closer look at PCP to see what it uses for the meta level > description for every metric. I thought this might be interesting for > you. Here you go: > > > - Data type: union of all C types, plus blob > - Semantics: counter, instant, descrete > - Units and scale: dimension and scale for space, time, count > > > Here are some examples: > > > kernel.all.load [1, 5 and 15 minute load average] > Data Type: float InDom: 60.2 0xf000002 > Semantics: instant Units: none > > kernel.percpu.cpu.user [percpu user CPU time metric from /proc/stat] > Data Type: 64-bit unsigned int InDom: 60.0 0xf000000 > Semantics: counter Units: millisec > > > For detailed info you can check out "man PMAPI" on any SLES box. > > > Matthias
If I am understanding this correctly, this is actually similar in concept to the XDR restructuring that I did for gmond. However the metadata and the value message are split into two different structures. The metadata is a struct that contains the basic metric description elements plus a blob (basically. It is really an array of additional elements). The value message is a union of all of the supported data types. Both message types (metadata, value) carry a metric ID header struct that defines the host, metric name and spoof indicator. Since this structure is basically the header for every XDR message, even before the XDR message type is determined, the host and metric can be identified. Take a look at lib/protocol.h. You asked about spoofing or IP proxying the other night. Creating a proxied metric metadata or value message is really no different than any other metric message. The difference is in the additional metadata that is added to the message. The following API will convert a regular metric message to a proxied message: Ganglia_metadata_add (ganglia_metric, SPOOF_HOST, host_name); Basically all this is doing is adding a proxied host name or IP as extra metadata to a metric message (metadata or value). Gmond looks at the SPOOF_HOST and alters the XDR packet with the appropriate host name. This is actually how gmetric now deals with actual metrics vs. spoofed metrics. Brad ------------------------------------------------------------------------- SF.Net email is sponsored by: The Future of Linux Business White Paper from Novell. From the desktop to the data center, Linux is going mainstream. Let it simplify your IT future. http://altfarm.mediaplex.com/ad/ck/8857-50307-18918-4 _______________________________________________ Ganglia-developers mailing list Ganglia-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/ganglia-developers
