The pmval Command - pcp Documentation Performance Co-Pilot Mar 16, 2021

The pmval command dumps the current values for the named performance metrics. For example, the following command reports the value of performance metric proc.nprocs once per second (by default), and produces output similar to this:

In this example, the number of running processes was reported once per second.

6.2. The pmrep Command 53

Where the semantics of the underlying performance metrics indicate that it would be sensible, pmval reports the rate of change or resource utilization.

For example, the following command reports idle processor utilization for each of four CPUs on the remote host dove, each five seconds apart, producing output of this form:

pmval -h dove -t 5sec -s 4 kernel.percpu.cpu.idle metric: kernel.percpu.cpu.idle

host: dove

semantics: cumulative counter (converting to rate) units: millisec (converting to time utilization) samples: 4

interval: 5.00 sec

cpu:1.1.0.a cpu:1.1.0.c cpu:1.1.1.a cpu:1.1.1.c

1.000 0.9998 0.9998 1.000

0.8989 0.9987 0.9997 0.9995

0.9568 0.9998 0.9996 1.000

Similarly, the following command reports disk I/O read rate every minute for just the disk /dev/disk1, and produces output similar to the following:

pmval -t 1min -i disk1 disk.dev.read metric: disk.dev.read

host: localhost

semantics: cumulative counter (converting to rate) units: count (converting to count / sec) samples: indefinite

interval: 60.00 sec disk1

33.67 48.71 52.33 11.33 2.333

The -r flag may be used to suppress the rate calculation (for metrics with counter semantics) and display the raw values of the metrics.

In the example below, manipulation of the time within the archive is achieved by the exchange of time control messages between pmval and pmtime.

pmval -g -a ${PCP_LOG_DIR}/pmlogger/myserver/20170731 kernel.all.load

The pmval command is documented by the pmval(1) man page, and annotated examples of the use of pmval can be found in the PCP Tutorials and Case Studies companion document.

6.4 The pminfo Command

The pminfo command displays various types of information about performance metrics available through the Perfor-mance Co-Pilot (PCP) facilities.

The -T option is extremely useful; it provides help text about performance metrics:

pminfo -T mem.util.cached mem.util.cached

Help:

Memory used by the page cache, including buffered file data.

This is in-memory cache for files read from the disk (the pagecache) but doesn't include SwapCached.

The -t option displays the one-line help text associated with the selected metrics. The -T option prints more verbose help text.

Without any options, pminfo verifies that the specified metrics exist in the namespace, and echoes those names.

Metrics may be specified as arguments to pminfo using their full metric names. For example, this command returns the following response:

pminfo hinv.ncpu network.interface.total.bytes hinv.ncpu

network.interface.total.bytes

A group of related metrics in the namespace may also be specified. For example, to list all of the hinv metrics you would use this command:

If no metrics are specified, pminfo displays the entire collection of metrics. This can be useful for searching for metrics, when only part of the full name is known. For example, this command returns the following response:

pminfo | grep nfs

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The -d option causes pminfo to display descriptive information about metrics (refer to the pmLookupDesc(3) man page for an explanation of this metadata information). The following command and response show use of the -d option:

pminfo -d proc.nprocs disk.dev.read filesys.free proc.nprocs

Data Type: 32-bit unsigned int InDom: PM_INDOM_NULL 0xffffffff Semantics: instant Units: none

disk.dev.read

Data Type: 32-bit unsigned int InDom: 60.1 0xf000001 Semantics: counter Units: count

filesys.free

Data Type: 64-bit unsigned int InDom: 60.5 0xf000005 Semantics: instant Units: Kbyte

The -l option causes pminfo to display labels about metrics (refer to the pmLookupLabels(3) man page for an explanation of this metadata information). If the metric has an instance domain, the labels associated with each instance of the metric is printed. The following command and response show use of the -l option:

pminfo -l -h shard kernel.pernode.cpu.user kernel.percpu.cpu.sys

inst [0 or "cpu0"] labels

{"agent":"linux","cpu":0,"device_type":"cpu","domainname":"acme.com","groupid":1000,