systemtap/pcp integration

[David Smith <dsmith@redhat.com>]

[-- Attachment #1: Type: text/plain, Size: 1035 bytes --]

Here's a small update on the prototype systemtap/pcp integration work
I'm doing. I've create a systemtap branch, called 'dsmith/mmv' that
contains all my work. Basically this work allows systemtap to create
'mmv' memory mapped files.

If you checkout and build that, then you should be able to run the
attached systemtap script. This script is a translation of pcp's example
python mmv script found in src/python/mmv.py.

Note that systemtap will create a file called 'mmv' in
/proc/systemtap/{MODULE_NAME}. I've just been using pcp's 'mmvdump'
utility to dump the contents of the /proc/systemtap/{MODULE_NAME}/mmv
file. Currently the pcp mmv pmda only looks in one place for mmv files,
but it might be possible to create a symbolic link to systemtap's mmv
file to make it happy.

The code works for the attached script, but I'm sure it is quite
fragile. Things like locking, error checking, documentation, etc. need
to be done.

-- 
David Smith
dsmith@redhat.com
Red Hat
http://www.redhat.com
256.217.0141 (direct)
256.837.0057 (fax)

[-- Attachment #2: mmv.stp --]
[-- Type: text/plain, Size: 1286 bytes --]

global inst0, inst1, counter_metric, instant_metric, indom_metric
global instant_value

probe begin
{
	inst0 = mmv_add_instance(0, "zero")
	inst1 = mmv_add_instance(1, "hero")
	printf("instances: %d, %d\n", inst0, inst1)

	indom0 = mmv_add_indom(1, "We can be heroes",
			       "Set of instances from zero to hero")
 	mmv_add_indom_instance(indom0, inst0)
 	mmv_add_indom_instance(indom0, inst1)

	printf("indom: %d\n", indom0)

	counter_metric = mmv_add_metric("counter", 1, MMV_TYPE_NUMBER,
				 	MMV_SEM_COUNTER,
					mmv_units(0, 0, 1, 0, 0, 0),
					0, "Example counter metric",
					"Yep, a test counter metric")
	instant_metric = mmv_add_metric("instant", 2, MMV_TYPE_NUMBER,
					MMV_SEM_INSTANT,
					mmv_units(0, 0, 0, 0, 0, 0), 0,
					"Example instant metric",
					"Yep, a test instantaneous metric")
	indom_metric = mmv_add_metric("indom", 3, MMV_TYPE_NUMBER,
				      MMV_SEM_DISCRETE,
				      mmv_units(0, 0, 0, 0, 0, 0),
				      1, "", "")
	printf("metrics: %d, %d, %d\n", counter_metric, instant_metric,
	       indom_metric)

	mmv_stats_start(42, 0)

	instant_value = mmv_lookup_value(instant_metric, 0)
	mmv_set_value(instant_value, 41)
	mmv_inc_value(instant_value, 2)
}

probe timer.s(1)
{
	mmv_inc_value(instant_value, 3)
}

probe end
{
	mmv_stats_stop()
}