pcp-vmstat(1)
NAME
pcp-vmstat, pmstat - high-level system performance overview
SYNOPSIS
pcp [pcp options] vmstat [interval [samples]] pmstat [-gLlPxz] [-A align] [-a archive] [-h host] [-H file] [-n pmnsfile] [-O offset] [-p port] [-S starttime] [-s samples] [-T endtime] [-t interval] [-Z timezone]
DESCRIPTION
pmstat provides a one line summary of system performance every interval unit of time (the default is 5 seconds). pmstat is intended to monitor system performance at the highest level, after which other tools may be used to examine subsystems in which potential performance problems may be observed in greater detail. pcp-vmstat is a simple wrapper for use with the pcp(1) command, providing a more familiar command line format for some users. It also enables the extended reporting option by default, see the -x option below. Multiple hosts may be monitored by supplying more than one host with multiple -h flags (for live monitoring) or by providing a name of the hostlist file, where each line contain one host name, with -H, or multiple -a flags (for retrospective monitoring from sets of archives). The -t option may be used to change the default reporting interval. The interval argument follows the syntax described in PCPIntro(1), and in the simplest form may be an unsigned integer (the implied units in this case are seconds). By default, pmstat fetches metrics by connecting to the Performance Metrics Collector Daemon (PMCD) on the local host. If the -L option is specified, then pmcd(1) is bypassed, and metrics are fetched from PMDAs on the local host using the standalone PM_CONTEXT_LOCAL variant of pmNewContext(3). When the -h option is specified, pmstat connects to the pmcd(1) on host and fetches metrics from there. As mentioned above, multiple hosts may be monitored by supplying multiple -h flags. Alternatively, if the -a option is used, the metrics are retrieved from the Performance Co-Pilot archive log files identified by archive, which is a comma-separated list of names, each of which may be the base name of an archive or the name of a directory containing one or more archives. Multiple sets of archives may be replayed by supplying multiple -a flags. When the -a flag is used, the -P flag may also be used to pause the output after each interval. Standalone mode can only connect to the local host, using a set of archives implies a host name, and nominating a host precludes using an archive, so the options -L, -a and -h are mutually exclusive. Normally pmstat operates on the default Performance Metrics Name Space (PMNS), however if the -n option is specified an alternative namespace is loaded from the file pmnsfile. If the -s the option is specified, samples defines the number of samples to be retrieved and reported. If samples is 0 or -s is not specified, pmstat will sample and report continuously - this is the default behavior. When processing a set of archives, pmstat may relinquish its own timing control, and operate as a ``slave'' of a pmtime(1) process that uses a GUI dialog to provide timing control. In this case, either the -g option should be used to start pmstat as the sole slave of a new pmtime(1) instance, or -p should be used to attach pmstat to an existing pmtime(1) instance via the IPC channel identified by the port argument. The -S, -T, -O and -A options may be used to define a time window to restrict the samples retrieved, set an initial origin within the time window, or specify a ``natural'' alignment of the sample times; refer to PCPIntro(1) for a complete description of these options. The -l option prints the last 7 characters of a hostname in summaries involving more than one host (when more than one -h option has been specified on the command line). The -x option (extended CPU metrics) causes two additional CPU metrics to be reported, namely wait for I/O ("wa") and virtualisation steal time ("st"). The output from pmstat is directed to standard output, and the columns in the report are interpreted as follows: loadavg The 1 minute load average. memory The swpd column indicates average swap space used during the interval, in Kbytes. The free column indicates average free memory during the interval, in Kbytes. The buff column indicates average buffer memory in use during the interval, in Kbytes. The cache column indicates average cached memory in use during the interval, in Kbytes. If the values become large, they are reported as Mbytes (m suffix) or Gbytes (g suffix). swap The metrics in this area of the kernel instrumentation are of varying value. We try to report the average number of pages that are paged in (pi) and out (po) per second during the interval. If the corresponding page swapping metrics are unavailable, we report the average rate per second of swap operations in (si) and out (so) during the interval. It is normal for the ``in'' values to be non-zero, but the system is suffering memory stress if the ``out'' values are non-zero over an extended period. If the values become large, they are reported as thousands of operations per second (K suffix) or millions of operations per second (M suffix). io The bi and bo columns indicate the average rate per second of block input and block output operations (respectfully) during the interval. Unless all file systems have a 1 Kbyte block size, these rates do not directly indicate Kbytes transferred. If the values become large, they are reported as thousands of operations per second (K suffix) or millions of operations per second (M suffix). system Interrupt rate (in) and context switch rate (cs). Rates are expressed as average operations per second during the interval. Note that the interrupt rate is normally at least HZ (the clock interrupt rate, usually 100) interrupts per second. If the values become large, they are reported as thousands of operations per second (K suffix) or millions of operations per second (M suffix). cpu Percentage of CPU time spent executing user and "nice user" code (us), system and interrupt processing code (sy), idle loop (id). If any values for the associated performance metrics are unavailable, the value appears as ``?'' in the output. By default, pmstat reports the time of day according to the local timezone on the system where pmstat is run. The -Z option changes the timezone to timezone in the format of the environment variable TZ as described in environ(7). The -z option changes the timezone to the local timezone at the host that is the source of the performance metrics, as identified via either the -h or -a options.
FILES
$PCP_VAR_DIR/pmns/*
default PMNS specification files
$PCP_VAR_DIR/config/pmlogger/config.pmstat
pmlogger(1) configuration for creating an archive suitable
for replay with pmstat
PCP ENVIRONMENT
Environment variables with the prefix PCP_ are used to parameterize the file and directory names used by PCP. On each installation, the file /etc/pcp.conf contains the local values for these variables. The $PCP_CONF variable may be used to specify an alternative configuration file, as described in pcp.conf(5).
SEE ALSO
PCPIntro(1), pmclient(1), pmtime(1), PMAPI(3), pmNewContext(3), pcp.conf(5) and pcp.env(5).
DIAGNOSTICS
All are generated on standard error, and are intended to be self- explanatory.
Opportunity
Personal Opportunity - Free software gives you access to billions of dollars of software at no cost. Use this software for your business, personal use or to develop a profitable skill. Access to source code provides access to a level of capabilities/information that companies protect though copyrights. Open source is a core component of the Internet and it is available to you. Leverage the billions of dollars in resources and capabilities to build a career, establish a business or change the world. The potential is endless for those who understand the opportunity.
Business Opportunity - Goldman Sachs, IBM and countless large corporations are leveraging open source to reduce costs, develop products and increase their bottom lines. Learn what these companies know about open source and how open source can give you the advantage.
Free Software
Free Software provides computer programs and capabilities at no cost but more importantly, it provides the freedom to run, edit, contribute to, and share the software. The importance of free software is a matter of access, not price. Software at no cost is a benefit but ownership rights to the software and source code is far more significant.
Free Office Software - The Libre Office suite provides top desktop productivity tools for free. This includes, a word processor, spreadsheet, presentation engine, drawing and flowcharting, database and math applications. Libre Office is available for Linux or Windows.
Free Books
The Free Books Library is a collection of thousands of the most popular public domain books in an online readable format. The collection includes great classical literature and more recent works where the U.S. copyright has expired. These books are yours to read and use without restrictions.
Source Code - Want to change a program or know how it works? Open Source provides the source code for its programs so that anyone can use, modify or learn how to write those programs themselves. Visit the GNU source code repositories to download the source.
Education
Study at Harvard, Stanford or MIT - Open edX provides free online courses from Harvard, MIT, Columbia, UC Berkeley and other top Universities. Hundreds of courses for almost all major subjects and course levels. Open edx also offers some paid courses and selected certifications.
Linux Manual Pages - A man or manual page is a form of software documentation found on Linux/Unix operating systems. Topics covered include computer programs (including library and system calls), formal standards and conventions, and even abstract concepts.
