Hi Marko,
----- Original Message -----
> Hi,
>
> please see below for a proposal for a new process level PMDA.
>
> There are other related PMDAs already (at least hotproc, linux_proc,
> and process) but I think this one complements the offering nicely
> with the ability to easily monitor certain processes (e.g., just say
> $procs = 'java' on the fly to start monitoring all java processes
> regardless of their PIDs) and also by providing e.g. per-process
> IO stats which are not easily (if at all) available from other PMDAs.
It sounds like there's alot of overlap here with hotproc.* - pmdaproc
nowadays provides hotproc.* metrics, thanks to Martins recent efforts,
which may not be widely known yet (not really following the advantage
to parsing pidstat over accessing proc.* via hotproc ... am I missing
something subtle there?).
Those new hotproc.* metrics do allow both a configuration file-based
mechanism (like this new PMDA) & also support a very dynamic pmstore
update model too, like:
# pmstore hotproc.control.config 'fname = "java"'
to set the process filtering on-the-fly (the above syntax may not be
100% correct, thats just from memory - it'll be close though).
Is there something missing from the hotproc.* metrics that this new
PMDA would provide Marko? I don't really follow the IO-stats comment
- there's no magic that pidstat can do that pmdaproc cannot AFAIK in
terms of querying the kernel for stats.
>From a quick look, the docs for the (recently-added-to-Linux) hotproc
metrics could be improved - Martins, could we find a way to report
help text for hotproc.control, hotproc.predicate, and hotproc.total?
And the pmdaproc(1) man page is a bit lacking in coverage of how to
use hotproc. Maybe a tutorial page would suit here too?
On a vaguely related note, we have had several requests for a PMAPI
pcp-pidstat(1) tool (that uses the proc.* metrics, supports archives,
and could swap in hotproc.* for proc.* via command line option). We
could also think of extending pcp-collectl(1) in a similar way, which
might answer that other question you had (elsewhere) perhaps.
cheers.
--
Nathan
|