This chapter describes the performance monitoring tools available in Performance Co-Pilot (PCP). This product provides a group of commands and tools for measuring system performance. Each tool is described completely by its own man page. The man pages are accessible through the man command. For example, the man page for the tool pmchart is viewed by entering the following command:
man pmchart |
The following major sections are covered in this chapter:
“The pmchart Tool”, describes pmchart, a useful charting tool that graphically monitors system performance.
“The pmgadgets Command”, presents pmgadgets, a graphical tool that displays system performance in a small area.
“The pmkstat Command”, discusses pmkstat, a utility that provides a periodic one-line summary of system performance.
“The pmdumptext Command”, discusses pmdumptext, a utility that shows the current values for named performance metrics.
“The pmval Command”, describes pmval, a utility that displays performance metrics in ASCII tables.
“The pmem Command”, discusses pmem, a utility that reports per-process memory usage statistics.
“The pminfo Command”, describes pminfo, a utility that displays information about performance metrics.
“The pmstore Command”, describes the use of the pmstore utility to arbitrarily set or reset selected performance metric values.
Further monitoring tools covering performance visualization and automated reasoning about performance are described in Chapter 5, “System Performance Visualization Tools” and Chapter 6, “Performance Metrics Inference Engine”.
The following sections describe the various graphical and text-based PCP tools used to monitor local or remote system performance.
The pmchart utility supports interactive selection and plotting of trends over time for arbitrarily selected performance metrics from one or more hosts and one or more domains of performance metrics. First, you enter the following command:
pmchart |
You then see the Performance Co-Pilot Chart window shown in Figure 4-1.
Normally, pmchart operates in live mode where performance metrics are fetched in real time and plotted against a time axis. The user can choose performance metrics and monitor the current values for these metrics from any host that is accessible on the network and has the PMCD server running.
When launched with the -a command line option, pmchart can also replay PCP archive logs of performance metrics created by pmlogger.
The man page for pmchart explains how to configure charts based on performance metrics, using either the Open View option of the File menu or the New Plot option of the File menu. Once charts have been configured and applied, the charts are placed in an expanded Performance Co-Pilot Chart window, as shown in Figure 4-2.
All metrics in the Performance Metrics Name Space (PMNS) with numeric value semantics can be graphed. By default, pmchart initially allows the user to select metrics to be plotted from the local host. However, the graphical user interface allows other hosts or archives to be chosen at any time as alternate sources of performance metrics and all metrics (independent of their source) are plotted on a common time axis.
For horizontal lines at major tick marks, see “Displaying Horizontal Lines”.
The -h command line option nominates an alternate default host to be used in preference to the local host.
The -a command line option may be used to start pmchart processing performance metrics from one or more PCP archive logs. The first named archive becomes the default source of performance metrics. This mode is particularly useful for retrospective comparisons and for postmortem analysis of performance problems, where a remote system is not directly accessible or a performance analyst is not available on site.
The pmchart utility examines the semantics of selected metrics, and where sensible, uses the metadata provided by the Performance Metrics Collection Subsystem (PMCS) to convert fetched metric values to a rate before plotting. In the case where different metrics are plotted in the same chart (for example, against a common Y-axis), the metrics must have the same dimension (taking into account any automatic rate conversion), but pmchart may scale metric values where necessary, to produce comparable values with common units and scale.
When replaying archive logs, the user may interactively control the current replay time, direction of replay, and replay rate, using the PCP time control dialog, as described in the “Time Duration and Control” in Chapter 3.
The pmchart tool uses the mouse buttons as follows:
| Left | The primary mouse button may be used to select the current chart by clicking anywhere in a specific chart. The current chart always has a border drawn around the graph area and its legend of metric names rendered in red. The Edit menu contains a variety of choices that operate only on the current chart. This mouse button also interacts with menus and dialog boxes in the usual manner. | |
| Middle | The middle mouse button is unused. | |
| Right | The secondary mouse button may be used to display metric values in a dialog box. Click this mouse button in the graph drawing area of any chart to display information about the nearest metric and its value at that point as plotted. The Metric Value Information dialog box remains visible until you dismiss it, and can be refreshed with new metric values by clicking this mouse button again, or updated automatically using the Show most Recent toggle button. |
A view in pmchart is a predefined collection of charts, typically constructed to display some common performance scenario. Default views are included in the PCP distribution, others are part of the various PCP add-on products, and others may be created by the pmchart end user. The Open View... option in the File menu launches a Select Performance View dialog box similar to Figure 4-3.
You may use this dialog to select one of the available views. The default PCP views include the following:
You can create your own custom views using the metric selection facilities, and save your views for later using the Save View... option of the File menu.
You can have pmchart display horizontal lines, usually in a lighter background color, at major tick marks by calling pmchart with the following arguments (quotes required):
% pmchart -xrm "PmChart*xrtYGridUseDefault: True" |
For greater convenience, you can place the following line in your $HOME/.Xresources file, to have pmchart always display horizontal lines:
PmChart*xrtYGridUseDefault: True |
The pmchart Metric Selection window, shown in Figure 4-4, allows interactive navigation of the Performance Metrics Name Space (PMNS) to create new chart configurations.
You can choose metrics, display information about metrics, change the current host or archive, select metric instances, and plot metric values on a common time axis. You bring up this window by choosing New Plot... from the File menu of pmchart.
Metric selection proceeds by navigating through the tree-structured PMNS. If you enter a partial metric specification in the Path field in the Metric Selection dialog, you can avoid having to navigate through the PMNS for the metrics you need. For example, if you enter network.interface, the window changes dynamically, as shown in Figure 4-5.
You can continue the selection process by choosing non-leaf nodes from the Nodes list, and finally a leaf node from the Metrics list. At this stage, the Path corresponds to a leaf node in the PMNS, as shown in Figure 4-6.
Once a metric has been selected, the Info button in the Metric Selection dialog launches the Metric Information dialog, as shown in Figure 4-7.
This dialog displays the name, unit, and semantics for the currently selected metric, along with the verbose help text that describes the metric, and optionally a description of the underlying instance domain.
Finally, you may have to select from several instances of a metric. In the example shown in Figure 4-7, you wish to monitor the input packet rate for some network interface(s). For the current source of performance metrics, there are two network interfaces configured. You must select one or more instances, as shown in Figure 4-8.
You can select multiple instances either by clicking and dragging up and down the list with the left mouse button, or by selecting the first instance and then using the Shift key (or Ctrl key) with the left mouse button to select one or more other instances.
From the File menu of pmchart when running in live mode, the Record (Stop Recording) option may be used to start (or stop) the creation of a PCP archive log. The archive log is created using pmlogger and includes the update interval and all of the performance metrics in the current pmchart configuration when recording begins.
| Note: Any changes made to the pmchart configuration after recording has been started will not be reflected in the archive log. For these to take effect, the recording must be stopped and restarted (thereby creating a second PCP archive log). |
When recording is started, a File Chooser dialog is launched, and the user must provide the name of a new file to be used as the PCP archive folio for the new archive (see “PCP Archive Folios” in Chapter 7). The recording session produces multiple files in the same directory as the archive folio.
If necessary, pmchart creates directories on the path to the named archive folio.
It is often convenient to maintain one directory for each new folio, or else one directory for each group of folios related by collector host(s), service type, or chart selection.
When recording is active, a small red indicator appears in the time control button, as shown at the bottom left of Figure 4-9.
If you choose File > Stop Recording, logging stops immediately. The red light in the lower left turns gray.
To start recording again, chose File > Record and specify a new archive folio name.
If you exit pmchart by choosing File > Quit, an Archive Recording Session-pmchart dialog similar to that shown in Figure 4-10 appears to remind you where the archive folio was created, and to confirm that recording should be terminated.
If you select Yes, recording stops immediately.
If you select No, recording continues. This is a useful way to continue archive logging without keeping pmchart active.
When using a video projector, or when making presentations to a large group, or as a result of personal preference, the default pastel color scheme used by pmchart may be inappropriate.
The Colors option in the Edit menu allows arbitrary changes to the colors of individual charts. For more global changes, you can override the defaults using the X11 resources that pmchart honors.
For example, create or add the following entries in the $HOME/.xrdb file:
PmChart*xrtForegroundColor: "green"
PmChart*xrtBackgroundColor: "black"
PmChart*xrtGraphForegroundColor: "rgb:00/b0/00"
PmChart*xrtGraphBackgroundColor: "black"
PmChart*xrtHeaderForegroundColor: "green"
PmChart*xrtHeaderBackgroundColor: "black"
PmChart*pmDefaultColors: rgb:ff/ff/00 rgb:00/ff/00 rgb:00/00/ff \
rgb:ff/ff/00 rgb:00/ff/ff rgb:ff/00/ff |
Use the following command to change the default color scheme for pmchart to one with bright primary colors on a black background:
xrdb -merge $HOME/.xrdb |
The pmchart Edit menu provides options and a dialog that you may use to change and customize the display as follows:
| Chart Style | Chooses from line, bar, stacked bar, area plot, and utilization. | |
| Chart Title and Legend... | Changes the chart title, and enable or disable the legend annotation at the top of each chart. | |
| Y-Axis Scaling... | Fixes the maximum and minimum values of the range on the Y-axis, or allow pmchart to adjust the range dynamically to reflect currently displayed values. | |
| Colors... | Customizes plot colors. | |
| Delete | Selects all charts, a complete chart, or individual plots from a chart. |
The pmchart Options menu provides another option for customizing the display:
The Options menu provides access to the PCP Time Control Dialog (as described in the “Time Duration and Control” in Chapter 3).
| Show Time Control | Exposes the dialog for the controlling pmtime instance, thereby allowing users to change the sampling interval. Selecting the Time Control button in the lower left corner of the main pmchart window also exposes the Time Control dialog. If the current source of performance metrics is one or more PCP archive logs, this same dialog may be used for temporal navigation within the archive(s). | |
| New Time Control | Detaches pmchart from the controlling pmtime instance and launches a new pmtime instance, initially dedicated to this pmchart. | |
| Launch New Pmchart | Starts a new pmchart, with shared pmtime control. |
The Print option in the File menu enables the current pmchart display to be printed in a variety of PostScript styles. The output can be saved in a file or sent directly to a printer.
The -o option for pmchart also provides the facility to produce Graphics Interchange Format (GIF) image snapshots of the pmchart display.
It is often convenient to publish performance summary information for the users of a particular computing environment. The pmchart tool, in combination with the pmsnap script and its associated control files, can be used to produce high-quality performance summary snapshot images in GIF format. These images can be incorporated into Web pages, reports, e-mail, or presentation material.
The following files and utilities are included in support of this feature:
Instructions for configuring pmsnap are in the man page. There is also a verbose comment at the head of the control file. The pmchart(1) man page is also useful.
The annotated examples in the pmchart chapter of the PCP Tutorial provide a guided illustration to a typical user's interactions with pmchart. The PCP Tutorial can be optionally installed as the pcp.man.tutorial subsystem. To view the pmchart chapter of the tutorial, open the following URL with your Web browser:
file:/var/pcp/Tutorial/pmchart.html |
The pmgadgets tool creates a small window containing a collection of graphical gadgets driven by performance metrics supplied by the PCP framework. Any numeric metric supported by PCP can be displayed.
| Note: In the current PCP release, pmgadgets is constrained to process performance metrics from real-time sources (and not PCP archive logs), although metrics from several different hosts may be displayed simultaneously in the same window. |
The layout of the gadgets and the performance metrics that lie behind them are specified in a configuration file, and pmgadgets is typically run on an existing configuration file or in conjunction with an application that automatically generates a configuration file. For example, pmgsys generates a configuration file for various IRIX performance metrics and feeds it to pmgadgets. The resulting display depends on the host configuration, but the display shown in Figure 4-11 is representative of a system with four CPUs, eleven disks on three controllers, and four network interfaces.
Other pmgadget front end tools such as pmgcluster, pmgevctr, pmgcisco, and pmgshping are not described in this chapter. For information about these tools, see the pmgcluster(1), pmgevctr(1), pmgcisco(1), and pmgshping(1) man pages.
The pmgadgets tool displays much the same information as pmchart, but more compactly, and with less historical information.
The pmgadgets specification language provides the ability to define the following gadgets and components:
Each visible gadget must be assigned a Cartesian position in the pmgadgets display.
By way of an example, the pmgadgets specification shown in Example 4-1 includes CPU, disk, and load average information from two hosts, and produces a customized pmgadgets display like the one shown in Figure 4-12.
Example 4-1. Specification File for pmgadgets
_colourlist cpuColours (blue3 red3 yellow3 cyan3 green3)
_legend diskLegend (
_default green3
15 yellow
40 orange
75 red
)
# host moomba
_label 70 12 "moomba"
_multibar 5 5 30 6
_metrics (
moomba:kernel.all.cpu.user
moomba:kernel.all.cpu.sys
moomba:kernel.all.cpu.intr
moomba:kernel.all.cpu.wait.total
moomba:kernel.all.cpu.idle
)
_maximum 0.0
_colourlist cpuColours
_bargraph 40 5 25 20
_metric moomba:kernel.all.load["1 minute"]
_max 1.0
_led 12 16 6 6
_metric moomba:disk.all.read _legend diskLegend
_led 25 16 6 6
_metric moomba:disk.all.write _legend diskLegend
# host gonzo
_label 70 39 "gonzo"
_multibar 5 32 30 6
_metrics (
gonzo:kernel.all.cpu.user
gonzo:kernel.all.cpu.sys
gonzo:kernel.all.cpu.intr
gonzo:kernel.all.cpu.wait.total
gonzo:kernel.all.cpu.idle
)
_maximum 0.0
_colourlist cpuColours
_bargraph 40 32 25 20
_metric gonzo:kernel.all.load["1 minute"]
_max 1.0
_led 12 43 6 6
_metric gonzo:disk.all.read _legend diskLegend
_led 25 43 6 6
_metric gonzo:disk.all.write _legend diskLegend |
In addition to the drill-down capabilities of pmgadgets, positioning the cursor over a gadget and entering a space character causes an information dialog to be exposed. This dialog tracks the current values of the performance metrics that are associated with the gadget as illustrated by the pmgadgets information dialog in Figure 4-13.
The pmgadgets(1) man page provides a complete description of the gadget specification language and the user interface controls of pmgadgets.
The pmkstat command provides a periodic, one-line summary of system performance. This command is intended to monitor system performance at the highest level, after which other tools may be used for examining subsystems to observe potential performance problems in greater detail. After entering the pmkstat command, you see output similar to the following, with successive lines appearing periodically:
pmkstat # hostname load avg: 0.26, interval: 5 sec, Thu Jan 19 12:30:13 1995 runq | memory | system | disks| cpu mem swp | free page | scall ctxsw intr| rd wr|usr sys idl wt 0 0 16268 0 64 19 2396 0 0 0 1 99 0 0 0 16264 0 142 45 2605 0 8 0 2 97 0 0 0 16268 0 308 62 2532 0 1 1 1 98 0 0 0 16268 0 423 88 2643 0 0 1 1 97 0 |
An additional line of output is added every five seconds. The update interval may be varied using the -t interval option.
The output from pmkstat is directed to standard output, and the columns in the report are interpreted as follows:
| runq | Average number of runnable processes in main memory (mem) and in swap memory (swp) during the interval. | |
| memory | The free column indicates average free memory during the interval, in kilobytes. The page column is the average number of page-out operations per second during the interval. I/O operations caused by these page-out operations are included in the disk write I/O rate. | |
| system | System call rate (scall), context switch rate (ctxsw), and interrupt rate (intr). Rates are expressed as average operations per second during the interval. | |
| disks | Aggregated physical read (rd) and write (wr) rates over all disks, expressed as physical I/O operations issued per second during the interval. These rates are independent of the I/O block size. | |
| cpu | Percentage of CPU time spent executing user code (usr), system and interrupt code (sys), idle loop (idl) and idle waiting for resources (wt), typically disk I/O. |
As with most PCP utilities, real-time metric, and archive logs are interchangeable.
For example, the following command uses the PCP archive log foo and the timezone of the host (tokyo) from which performance metrics in the archive were collected:
pmkstat -a foo -z Note: timezone set to local timezone of host "tokyo" # tokyo load avg: 1.06, interval: 5 sec, Thu Feb 2 08:42:55 1995 runq | memory | system | disks | cpu mem swp| free page| scall ctxsw intr| rd wr|usr sys idl wt 0 0 4316 0 195 64 2242 32 21 0 3 8 89 0 0 3976 0 279 86 2143 50 17 0 5 8 87 1 0 3448 0 186 63 2304 35 14 0 4 9 87 0 0 4364 0 254 81 2385 35 0 0 4 9 87 0 0 3696 0 266 92 2374 41 0 0 3 9 88 0 0 2668 42 237 81 2400 44 2 1 4 7 89 0 0 4644 100 206 68 2590 25 1 0 3 5 91 0 0 5384 0 174 63 2296 32 22 0 2 8 89 0 0 4736 0 189 65 2197 31 28 0 3 8 89 pmFetch: End of PCP archive log |
For complete information on pmkstat usage and command line options, see the pmkstat(1) man page.
The pmdumptext command displays performance metrics in ASCII tables, suitable for export into databases or report generators. It is a flexible command. For example, the following command provides continuous memory statistics on a host named serv:
pmdumptext -imu -h serv -f `%H:%M:%S' mem.util
Metric kernel fs_ctl _dirty _clean free user
Units b b b b b b
20:14:28 99.14M 6.03M 0.85M 98.42M 0.17G 0.16G |
See the pmdumptext(1) man page for more information.
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:
pmval proc.nprocs
metric: proc.nprocs
host: localhost
semantics: instantaneous value
units: none
samples: indefinite
interval: 1.00 sec
73
72
70
75
75 |
In this example, the number of running processes was reported once per second.
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 moomba, each five seconds apart, producing output of this form:
pmval -h moomba -t 5sec -s 4 kernel.percpu.cpu.idle
metric: kernel.percpu.cpu.idle
host: moomba
semantics: cumulative counter (converting to rate)
units: millisec (converting to time utilization)
samples: 4
interval: 5.00 sec
cpu0 cpu1 cpu2 cpu3
0.8193 0.7933 0.4587 0.8193
0.7203 0.5822 0.8563 0.7303
0.6100 0.6360 0.7820 0.7960
0.8276 0.7037 0.6357 0.6997 |
Similarly, the following command reports disk I/O read rate every minute for just the disk /dev/dsk/dks0d1, and produces output similar to the following:
pmval -t 1min -i dks0d1 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
dks0d1
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.
When used in conjunction with a PCP archive, the -g option may be used to associate a PCP time control dialog (see “Time Duration and Control” in Chapter 3) with the execution of pmval to support temporal navigation within the archive. 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 /var/adm/pcplog/myserver/960801 |
The pmval command is documented by the pmval(1) man page, and annotated examples of the use of pmval are in the PCP Tutorial.
The pmem command reports per-process memory usage statistics within the PCP framework.
Both virtual size and prorated physical memory usage are reported. The virtual memory usage statistics represent the total virtual size of each process, irrespective of how many pages are valid (resident). Prorated physical memory statistics indicate real memory usage (only valid pages are counted) and are prorated on a per-page basis between all processes that reference each page. Thus the prorated physical memory counts reflect the real memory demands for individual processes in the context of the current process mix.
The output of pmem can be very large. Here is an abbreviated example of pmem output:
Host: gonzo Configured: 65536 Free:18380 Tue Jul 9 16:45:08 1996
pid ppid user vtxt ptxt vdat pdat vshm pshm command
1 0 root 232 144 84 76 0 0 /etc/init
832 827 root 3204 1013 5796 3096 0 0 /usr/bin/X11/Xsg
221 1 root 1424 54 156 84 0 0 /usr/lib/saf/sad
838 827 root 2948 36 268 75 0 0 /usr/bin/X11/xdm
86 1 root 1264 32 144 76 0 0 /usr/etc/syslogd
182 1 root 1476 129 596 387 0 0 /usr/etc/rpcbind
827 1 root 2948 13 252 22 0 0 /usr/bin/X11/xdm
172 1 root 1276 52 148 100 0 0 /usr/etc/routed
Total vtxt ptxt vdat pdat vshm pshm 77 user processes
121M 36256 0 = 157M virtual
13982 20194 0 = 34176 physical |
The columns report the following information:
| pid | Process ID number. |
| ppid | Parent process ID number. |
| user | Login name of the process owner. |
| vtxt | Total virtual memory used by text (executable code) regions mapped by the process. |
| ptxt | Prorated physical memory used by text regions. |
| vdat | Total virtual memory used by all non-executable regions, excluding shared memory regions. This includes initialized data, bss, and stack but not shared memory regions. |
| pdat | Prorated physical memory used by all data regions (data, bss, and stack but not shared memory regions). |
| vshm | Total virtual memory used by all shared memory regions. |
| pshm | Prorated physical memory used by shared memory regions. |
| command | The command and arguments. |
For complete information on pmem usage and command line options, see the pmem(1) man page.
The pminfo command displays various types of information about performance metrics available through the Performance Co-Pilot (PCP) facilities.
The -T option is extremely useful; it provides help text about performance metrics:
pminfo -T mem.util.fs_dirty mem.util.fs_dirty Help: The amount of memory in Kbytes that is holding file system data. |
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 Name Space, 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 Name Space may also be specified. For example, to list all of the hinv metrics you would use this command:
pminfo hinv hinv.ncpu hinv.cpuclock hinv.dcache hinv.icache hinv.secondarycache hinv.physmem hinv.pmeminterleave hinv.ndisk |
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 nfs.client.badcalls nfs.client.badcalls nfs.client.calls nfs.client.nclget nfs.client.nclsleep nfs.client.reqs nfs.server.badcalls nfs.server.calls nfs.server.reqs nfs.client.badcalls nfs.client.calls nfs.client.nclget nfs.client.nclsleep nfs.client.reqs nfs.server.badcalls nfs.server.calls nfs.server.reqs |
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 int InDom: PM_INDOM_NULL 0xffffffff
Semantics: instant Units: none
disk.dev.read
Data Type: 32-bit unsigned int InDom: 1.2 0x400002
Semantics: counter Units: count
filesys.free
Data Type: 32-bit int InDom: 1.7 0x400007
Semantics: instant Units: Kbyte |
The -f option to pminfo forces the current value of each named metric to be fetched and printed. In the example below, all metrics in the group hinv are selected:
pminfo -f hinv
hinv.ncpu
value 1
hinv.cpuclock
value 100
hinv.dcache
value 8192
hinv.icache
value 8192
hinv.secondarycache
value 1048576
hinv.physmem
value 64
hinv.pmeminterleave
value 0
hinv.ndisk
value 1 |
The -h option directs pminfo to retrieve information from the specified host. If the metric has an instance domain, the value associated with each instance of the metric is printed:
pminfo -h babylon.engr.sgi.com -f filesys.mountdir
filesys.mountdir
inst [1 or "/dev/root"] value "/"
inst [2 or "/dev/dsk/dks1d3s7"] value "/usr2"
inst [3 or "/dev/dsk/dks3d1s7"] value "/dbv"
inst [4 or "/dev/dsk/dks3d4s7"] value "/dbv/d4"
inst [5 or "/dev/dsk/dks3d2s7"] value "/dbv/d2"
inst [6 or "/dev/dsk/dks3d3s7"] value "/dbv/d3"
inst [7 or "/dev/dsk/dks2d4s7"] value "/vicepb"
inst [8 or "/dev/dsk/xlv/build9"] value "/build9"
inst [9 or "/dev/dsk/xlv/build8"] value "/build8"
inst [10 or "/dev/dsk/xlv/lv9.xfs"] value "/lv9"
inst [11 or "/dev/dsk/dks2d5s7"] value "/usenet"
inst [12 or "/dev/dsk/xlv/work"] value "/usr/work"
inst [13 or "/dev/dsk/xlv/build10"] value "/build10"
inst [14 or "/dev/dsk/xlv/dist"] value "/usr/dist"
inst [15 or "/dev/dsk/xlv/people"] value "/usr/people"
inst [16 or "/dev/dsk/xlv/build12"] value "/build12"
inst [17 or "/dev/dsk/xlv/build11"] value "/build11" |
The -m option prints the Performance Metric Identifiers (PMIDs) of the selected metrics. This is useful for finding out which PMDA supplies the metric. For example, the output below identifies the PMDA supporting domain 4 (the leftmost part of the PMID) as the one supplying information for the metric environ.extrema.mintemp:
pminfo -m environ.extrema.mintemp environ.extrema.mintemp PMID: 4.0.3 |
The -v option verifies that metric definitions in the PMNS correspond with supported metrics, and checks that a value is available for the metric. Descriptions and values are fetched, but not printed. Only errors are reported.
Some instance domains are not enumerable. That is, it is not possible to ask for all of the instances at once. Only explicit instances may be fetched from such instance domains. This is because instances in such a domain may have a very short lifetime or the cost of obtaining all of the instances at once is very high. The proc metrics are an example of such an instance domain. The -f option is not able to fetch metrics with non-enumerable instance domains; however, the -F option tells pminfo to obtain a snapshot of all of the currently available instances in the instance domain and then to retrieve a value for each.
Complete information on the pminfo command is found in the pminfo(1) man page. There are examples of the use of pminfo in the PCP Tutorial.
From time to time you may wish to change the value of a particular metric. Some metrics are counters that may need to be reset, and some are simply control variables for agents that collect performance metrics. When you need to change the value of a metric for any reason, the command to use is pmstore.
| Note: For obvious reasons, the ability to arbitrarily change the value of a performance metric is not supported. Rather, the PMCS selectively allows some metrics to be modified in a very controlled fashion. |
The basic syntax of the command is as follows:
pmstore metricname value |
There are also command line flags to further specify the action. For example, the -i option restricts the change to one or more instances of the performance metric.
The value may be in one of several forms, according to the following rules:
If the metric has an integer type, then value should consist of an optional leading hyphen, followed either by decimal digits or “0x” and some hexadecimal digits; “0X” is also acceptable instead of “0x.”
If the metric has a floating point type, then value should be in the form of an integer (described above), a fixed point number, or a number in scientific notation.
If the metric has a string type, then value is interpreted as a literal string of ASCII characters.
If the metric has an aggregate type, then an attempt is made to interpret value as an integer, a floating point number, or a string. In the first two cases, the minimal word length encoding is used; for example, “123” would be interpreted as a four-byte aggregate, and “0x100000000” would be interpreted as an eight-byte aggregate.
The following example illustrates the use of pmstore to enable performance metrics collection in the txmon PMDA (see /usr/pcp/pmdas/txmon for the source code of the txmon PMDA). When the metric txmon.control.level has the value 0, no performance metrics are collected. Values greater than 0 enable progressively more verbose instrumentation.
pminfo -f txmon.count
txmon.count
No value(s) available!
pmstore txmon.control.level 1
txmon.control.level old value=0 new value=1
pminfo -f txmon.count
txmon.count
inst [0 or "ord-entry"] value 23
inst [1 or "ord-enq"] value 11
inst [2 or "ord-ship"] value 10
inst [3 or "part-recv"] value 3
inst [4 or "part-enq"] value 2
inst [5 or "part-used"] value 1
inst [6 or "b-o-m"] value 0 |
For complete information on pmstore usage and syntax, see the pmstore(1) man page.