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NAME

       pmie - inference engine for performance metrics

SYNOPSIS

       pmie  [-bCdeFfPqvVWxXz?]  [-a archive] [-A align] [-c filename] [-h host] [-l logfile] [-m
       note] [-j stompfile] [-n pmnsfile] [-o format] [-O offset] [-S  starttime]  [-t  interval]
       [-T endtime] [-U username] [-Z timezone] [filename ...]

DESCRIPTION

       pmie  accepts a collection of arithmetic, logical, and rule expressions to be evaluated at
       specified frequencies.  The base data for the expressions consists of performance  metrics
       values  delivered  in  real-time  from any host running the Performance Metrics Collection
       Daemon (PMCD), or using historical data from Performance Co-Pilot (PCP) archives.

       As well as computing arithmetic and  logical  values,  pmie  can  execute  actions  (popup
       alarms,  write  system  log  messages,  and  launch  programs)  in  response  to specified
       conditions.  Such actions are extremely useful in  detecting,  monitoring  and  correcting
       performance related problems.

       The expressions to be evaluated are read from configuration files specified by one or more
       filename arguments.  In the absence of any filename, expressions are  read  from  standard
       input.

       Output from pmie is directed to standard output and standard error as follows:

       stdout
            Expression values printed in the verbose -v mode and the output of print actions.

       stderr
            Error  and  warning messages for any syntactic or semantic problems during expression
            parsing, and  any  semantic  or  performance  metrics  availability  problems  during
            expression evaluation.

OPTIONS

       The available command line options are:

       -a archive, --archive=archive
            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  written  by
            pmlogger(1).   Multiple  instances  of  the -a flag may appear on the command line to
            specify a list of sets of archives.  In this case, it is required that only  one  set
            of  archives be present for any one host.  Also, any explicit host names occurring in
            a pmie expression must match the host name recorded in one of the archive labels.  In
            the  case  of multiple sets of archives, timestamps recorded in the archives are used
            to ensure temporal consistency.

       -A align, --align=align
            Force the initial time window to be aligned on the boundary of a  natural  time  unit
            align.  Refer to PCPIntro(1) for a complete description of the syntax for align.

       -b, --buffer
            Output will be line buffered and standard output is attached to standard error.  This
            is most useful for background execution in conjunction with the -l  option.   The  -b
            option is always used for pmie instances launched from pmie_check(1).

       -c config, --config=config
            An alternative to specifying filename at the end of the command line.

       -C, --check
            Parse  the  configuration  file(s)  and  exit before performing any evaluations.  Any
            errors in the configuration file are reported.

       -d, --interact
            Normally pmie would be launched as a non-interactive process to  monitor  and  manage
            the  performance  of  one  or  more  hosts.   Given the -d flag however, execution is
            interactive and the user is presented with a menu of options.   Interactive  mode  is
            useful mainly for debugging new expressions.

       -e, --timestamp
            When  used  with -V, -v or -W, this option forces timestamps to be reported with each
            expression.  The timestamps are in  ctime(3)  format,  enclosed  in  parenthesis  and
            appear after the expression name and before the expression value, e.g.
                 expr_1 (Tue Feb  6 19:55:10 2001): 12

       -f, --foreground
            If  the  -l option is specified and there is no -a option (i.e. real-time monitoring)
            then pmie is run as a daemon in the background (in all other cases foreground is  the
            default).  The -f (and -F, see below) options force pmie to be run in the foreground,
            independent of any other options.

       -F, --systemd
            Like -f, the -F option runs pmie in the foreground, but also does  some  housekeeping
            (like  create  a pid file, change user id and notify systemd(1) when pmie has started
            or is shutting down).  This is intended for use when pmie is launched from systemd(1)
            and  the  daemonising  has  already  been  done.   The -f and -F options are mutually
            exclusive.

       -h host, --host=host
            By default performance data is fetched from the local host (in real-time mode) or the
            host  for the first named set of archives on the command line (in archive mode).  The
            host argument overrides this default.  It does not override hosts explicitly named in
            the  expressions  being  evaluated.  The host argument is interpreted as a connection
            specification for pmNewContext, and is  later  mapped  to  the  remote  pmcd's  self-
            reported  host  name for reporting purposes.  See also the %h vs. %c substitutions in
            rule action strings below.

       -j file
            An alternative STOMP protocol configuration is loaded from stompfile.  If this option
            is  not  used,  and  the  stomp  action  is  used  in  any rule, the default location
            $PCP_SYSCONF_DIR/pmie/config/stomp will be used.

       -l logfile, --logfile=logfile
            Standard error is sent to logfile.

       -m note, --note=note
            Used  to  indicate  where  pmie  has  been  launched  from,  e.g.  pmie_check(1)  and
            pmie_daily(1)  use -m pmie_check and this is used by pmie to determine if it needs to
            be restarted should the PMCD hostname change, as described in  the  HOSTNAME  CHANGES
            section below.

       -n pmnsfile, --namespace=pmnsfile
            An  alternative  Performance  Metrics  Name  Space  (PMNS)  is  loaded  from the file
            pmnsfile.

       -o format, --format=format
            When precessing performance data from an archive,  the  -o  option  may  be  used  to
            specify  an  alternate  output  format  when  a  rule  action  is  executed.  See the
            DIFFERENCES IN HOST AND ARCHIVE MODES section for a description  of  how  the  output
            format may be constructed.

       -O origin, --origin=origin
            Specify  the  origin of the time window.  See PCPIntro(1) for complete description of
            this option.

       -P, --primary
            Identifies this as the primary  pmie  instance  for  a  host.   See  the  ``AUTOMATIC
            RESTART'' section below for further details.

       -q, --quiet
            Suppresses  diagnostic  messages that would be printed to standard output by default,
            especially the "evaluator exiting" message as this can confuse scripts.

       -S starttime, --start=starttime
            Specify the starttime of the time window.  See PCPIntro(1) for  complete  description
            of this option.

       -t interval, --interval=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).  The value is used to determine the sample interval for expressions that do
            not explicitly set their sample interval using  the  pmie  variable  delta  described
            below.  The default is 10.0 seconds.

       -T endtime, --finish=endtime
            Specify  the endtime of the time window.  See PCPIntro(1) for complete description of
            this option.

       -U username, --username=username
            User account under which to run pmie.  The default is the current  user  account  for
            interactive  use.   When  run  as a daemon, the unprivileged "pcp" account is used in
            current versions of PCP, but in older versions the  superuser  account  ("root")  was
            used by default.

       -v   Unless  one  of  the  verbose  options  -V,  -v  or  -W  appears on the command line,
            expressions are evaluated silently, the only output is as a  result  of  any  actions
            being  executed.  In the verbose mode, specified using the -v flag, the value of each
            expression is printed as it is evaluated.  The values are in canonical  units;  bytes
            in the dimension of ``space'', seconds in the dimension of ``time'' and events in the
            dimension of ``count''.  See pmLookupDesc(3) for details of the  supported  dimension
            and  scaling  mechanisms  for  performance  metrics.   The  verbose mode is useful in
            monitoring the value of given expressions, evaluating  derived  performance  metrics,
            passing  these  values  on to other tools for further processing and in debugging new
            expressions.

       -V, --verbose
            This option has the same effect as the -v option, except that the name  of  the  host
            and instance (if applicable) are printed as well as expression values.

       -W   This  option  has  the  same effect as the -V option described above, except that for
            boolean expressions, only those names and values that make the  expression  true  are
            printed.   These  are the same names and values accessible to rule actions as the %h,
            %i, %c and %v bindings, as described below.

       -x, --secret-agent
            Execute in domain agent mode.  This mode is  used  within  the  Performance  Co-Pilot
            product  to  derive  values for summary metrics, see pmdasummary(1).  Only restricted
            functionality is available in this mode (expressions with actions may not be used).

       -X, --secret-applet
            Run in secret applet mode (thin client).

       -z, --hostzone
            Change the reporting timezone to the timezone of the host that is the source  of  the
            performance metrics, as identified via either the -h option or the first named set of
            archives (as described above for the -a option).

       -Z timezone, --timezone=timezone
            Change the reporting timezone to timezone in the format of the  environment  variable
            TZ as described in environ(7).

       -?, --help
            Display usage message and exit.

EXAMPLES

       The  following  example  expressions demonstrate some of the capabilities of the inference
       engine.

       The directory $PCP_DEMOS_DIR/pmie contains a number of other annotated  examples  of  pmie
       expressions.

       The  variable  delta  controls  expression  evaluation frequency.  Specify that subsequent
       expressions be evaluated once a second, until further notice:

            delta = 1 sec;

       If the total context switch rate exceeds 10000 per second per CPU, then display  an  alarm
       notifier:

            kernel.all.pswitch / hinv.ncpu > 10000 count/sec
            -> alarm "high context switch rate %v";

       If  the  high  context  switch  rate  is sustained for 10 consecutive samples, then launch
       top(1) in an xterm(1) window to monitor processes, but  do  this  at  most  once  every  5
       minutes:

            all_sample (
                kernel.all.pswitch @0..9 > 10 Kcount/sec * hinv.ncpu
            ) -> shell 5 min "xterm -e 'top'";

       The following rules are evaluated once every 20 seconds:

            delta = 20 sec;

       If  any  disk is performing more than 60 I/Os per second, then print a message identifying
       the busy disk to standard output and launch dkvis(1):

            some_inst (
                disk.dev.total > 60 count/sec
            ) -> print "busy disks:" " %i" &
                 shell 5 min "dkvis";

       Refine the preceding rule to apply only between the hours of 9am and 5pm, and to require 3
       of 4 consecutive samples to exceed the threshold before executing the action:

            $hour >= 9 && $hour <= 17 &&
            some_inst (
              75 %_sample (
                disk.dev.total @0..3 > 60 count/sec
              )
            ) -> print "disks busy for 20 sec:" " [%h]%i";

       The following two rules are evaluated once every 10 minutes:

            delta = 10 min;

       If  either the / or the /usr filesystem is more than 95% full, display an alarm popup, but
       not if it has already been displayed during the last 4 hours:

            filesys.free #'/dev/root' /
                filesys.capacity #'/dev/root' < 0.05
            -> alarm 4 hour "root filesystem (almost) full";

            filesys.free #'/dev/usr' /
                filesys.capacity #'/dev/usr' < 0.05
            -> alarm 4 hour "/usr filesystem (almost) full";

       The following rule requires a machine that supports the lmsensors metrics.  If the machine
       environment  temperature  rises  more  than  2 degrees over a 10 minute interval, write an
       entry in the system log:

            lmsensors.coretemp_isa.temp1 @0 - lmsensors.coretemp_isa.temp1 @1 > 2
            -> alarm "temperature rising fast" &
               syslog "machine room temperature rise alarm";

       And something interesting if you have performance problems with your Oracle database:

            // back to 30sec evaluations
            delta = 30 sec;
            sid = "ptg1";       # $ORACLE_SID setting
            lid = "223";        # latch ID from v$latch
            lru = "#'$sid/$lid cache buffers lru chain'";
            host = ":moomba.melbourne.sgi.com";
            gets = "oracle.latch.gets $host $lru";
            total = "oracle.latch.gets $host $lru +
                     oracle.latch.misses $host $lru +
                     oracle.latch.immisses $host $lru";

            $total > 100 && $gets / $total < 0.2
            -> alarm "high lru latch contention in database $sid";

       The following ruleset will emit exactly one message  depending  on  the  availability  and
       value of the 1-minute load average.

            delta = 1 minute;
            ruleset
                 kernel.all.load #'1 minute' > 10 * hinv.ncpu ->
                     print "extreme load average %v"
            else kernel.all.load #'1 minute' > 2 * hinv.ncpu ->
                     print "moderate load average %v"
            unknown ->
                     print "load average unavailable"
            otherwise ->
                     print "load average OK"
            ;

       The  following  rule will emit a message when some filesystem is more than 75% full and is
       filling at a rate that if sustained would fill the filesystem to  100%  in  less  than  30
       minutes.

            some_inst (
                100 * filesys.used / filesys.capacity > 75 &&
                filesys.used + 30min * (rate filesys.used) > filesys.capacity
            ) -> print "filesystem will be full within 30 mins:" " %i";

       If  the  metric mypmda.errors counts errors then the following rule will emit a message if
       the rate of errors exceeds 1 per second provided the error count is less than 100.

            mypmda.errors > 1 && instant mypmda.errors < 100
            -> print "high error rate: %v";

QUICK START

       The pmie specification language is powerful and large.

       To expedite rapid development of pmie rules, the pmieconf(1) tool provides a facility  for
       generating  a  pmie configuration file from a set of generalized pmie rules.  The supplied
       set of rules covers a wide range of performance scenarios.

       The Performance Co-Pilot User's and Administrator's Guide provides  a  detailed  tutorial-
       style chapter covering pmie.

EXPRESSION SYNTAX

       This  description  is  terse  and  informal.  For a more comprehensive description see the
       Performance Co-Pilot User's and Administrator's Guide.

       A pmie specification is a sequence of semicolon terminated expressions.

       Basic operators are modeled on the arithmetic, relational and Boolean operators of  the  C
       programming  language.   Precedence rules are as expected, although the use of parentheses
       is encouraged to enhance readability and remove ambiguity.

       Operands are performance metric names (see PMNS(5)) and the normal literal constants.

       Operands involving performance metrics  may  produce  sets  of  values,  as  a  result  of
       enumeration in the dimensions of hosts, instances and time.  Special qualifiers may appear
       after a performance metric name to define the enumeration in each dimension.  For example,

           kernel.percpu.cpu.user :foo :bar #cpu0 @0..2

       defines 6 values corresponding to the time spent executing in user mode on CPU  0  on  the
       hosts ``foo'' and ``bar'' over the last 3 consecutive samples.  The default interpretation
       in the absence of : (host), # (instance) and @ (time) qualifiers is all instances  at  the
       most recent sample time for the default source of PCP performance metrics.

       Host  and  instance  names  that  do  not  follow  the  rules for variables in programming
       languages, i.e. alphabetic optionally followed by alphanumerics,  should  be  enclosed  in
       single quotes.

       Expression  evaluation  follows the law of ``least surprises''.  Where performance metrics
       have the semantics of a counter, pmie will automatically convert  to  a  rate  based  upon
       consecutive  samples and the time interval between these samples.  All numeric expressions
       are evaluated in double  precision,  and  where  appropriate,  automatically  scaled  into
       canonical units of ``bytes'', ``seconds'' and ``counts''.

       A rule is a special form of expression that specifies a condition or logical expression, a
       special operator (->) and actions to be performed when the condition is found to be true.

       The following table summarizes the basic pmie operators:

                   ┌────────────────┬────────────────────────────────────────────────┐
                   │   Operators    │                  Explanation                   │
                   ├────────────────┼────────────────────────────────────────────────┤
                   │+ - * /         │ Arithmetic                                     │
                   │< <= == >= > != │ Relational (value comparison)                  │
                   │! && ||         │ Boolean                                        │
                   │->              │ Rule                                           │
                   │rising          │ Boolean, false to true transition              │
                   │falling         │ Boolean, true to false transition              │
                   │rate            │ Explicit rate conversion (rarely required)     │
                   │instant         │ No automatic rate conversion (rarely required) │
                   └────────────────┴────────────────────────────────────────────────┘
       All operators are supported for numeric-valued  operands  and  expressions.   For  string-
       valued operands, namely literal string constants enclosed in double quotes or metrics with
       a data type of string (PM_TYPE_STRING), only the operators == and != are supported.

       The rate and instant operators are the logical inverse of one another,  so  an  arithmetic
       expression  expr  is equal to rate instant expr.  The more useful cases involve using rate
       with a metric that is not a counter to determine the rate of change over time  or  instant
       with  a  metric that is a counter to determine if the current value is above or below some
       threshold.

       Aggregate operators may be used to aggregate or summarize along one dimension  of  a  set-
       valued  expression.   The following aggregate operators map from a logical expression to a
       logical expression of lower dimension.

                  ┌─────────────────────────┬─────────────┬──────────────────────────┐
                  │       Operators         │    Type     │       Explanation        │
                  ├─────────────────────────┼─────────────┼──────────────────────────┤
                  │some_inst                │ Existential │ True if at least one set │
                  │some_host                │             │ member is true in the    │
                  │some_sample              │             │ associated dimension     │
                  ├─────────────────────────┼─────────────┼──────────────────────────┤
                  │all_inst                 │ Universal   │ True if all set members  │
                  │all_host                 │             │ are true in the          │
                  │all_sample               │             │ associated dimension     │
                  ├─────────────────────────┼─────────────┼──────────────────────────┤
                  │N%_inst                  │ Percentile  │ True if at least N       │
                  │N%_host                  │             │ percent of set members   │
                  │N%_sample                │             │ are true in the          │
                  │                         │             │ associated dimension     │
                  └─────────────────────────┴─────────────┴──────────────────────────┘
       The  following  instantial  operators  may be used to filter or limit a set-valued logical
       expression,  based  on  regular  expression  matching  of  instance  names.   The  logical
       expression  must be a set involving the dimension of instances, and the regular expression
       is of the form used by egrep(1) or the Extended Regular Expressions of regcomp(3).

                       ┌─────────────┬──────────────────────────────────────────┐
                       │ Operators   │               Explanation                │
                       ├─────────────┼──────────────────────────────────────────┤
                       │match_inst   │ For each value of the logical expression │
                       │             │ that is ``true'', the result is ``true'' │
                       │             │ if the associated instance name matches  │
                       │             │ the regular expression.  Otherwise the   │
                       │             │ result is ``false''.                     │
                       ├─────────────┼──────────────────────────────────────────┤
                       │nomatch_inst │ For each value of the logical expression │
                       │             │ that is ``true'', the result is ``true'' │
                       │             │ if the associated instance name does not │
                       │             │ match the regular expression.  Otherwise │
                       │             │ the result is ``false''.                 │
                       └─────────────┴──────────────────────────────────────────┘
       For example, the expression below will be ``true'' for disks attached to controllers 2  or
       3 performing more than 20 operations per second:
            match_inst "^dks[23]d" disk.dev.total > 20;

       The  following  aggregate  operators  map  from  an arithmetic expression to an arithmetic
       expression of lower dimension.

                   ┌─────────────────────────┬───────────┬──────────────────────────┐
                   │       Operators         │   Type    │       Explanation        │
                   ├─────────────────────────┼───────────┼──────────────────────────┤
                   │min_inst                 │ Extrema   │ Minimum value across all │
                   │min_host                 │           │ set members in the       │
                   │min_sample               │           │ associated dimension     │
                   ├─────────────────────────┼───────────┼──────────────────────────┤
                   │max_inst                 │ Extrema   │ Maximum value across all │
                   │max_host                 │           │ set members in the       │
                   │max_sample               │           │ associated dimension     │
                   ├─────────────────────────┼───────────┼──────────────────────────┤
                   │sum_inst                 │ Aggregate │ Sum of values across all │
                   │sum_host                 │           │ set members in the       │
                   │sum_sample               │           │ associated dimension     │
                   ├─────────────────────────┼───────────┼──────────────────────────┤
                   │avg_inst                 │ Aggregate │ Average value across all │
                   │avg_host                 │           │ set members in the       │
                   │avg_sample               │           │ associated dimension     │
                   └─────────────────────────┴───────────┴──────────────────────────┘
       The aggregate operators  count_inst,  count_host  and  count_sample  map  from  a  logical
       expression  to  an  arithmetic expression of lower dimension by counting the number of set
       members for which the expression is true in the associated dimension.

       For action rules, the following actions are defined:

                          ┌──────────┬────────────────────────────────────────┐
                          │Operators │              Explanation               │
                          ├──────────┼────────────────────────────────────────┤
                          │alarm     │ Raise a visible alarm with xconfirm(1) │
                          │print     │ Display on standard output             │
                          │shell     │ Execute with sh(1)                     │
                          │stomp     │ Send a STOMP message to a JMS server   │
                          │syslog    │ Append a message to system log file    │
                          └──────────┴────────────────────────────────────────┘
       Multiple actions may be separated by  the  &  and  |  operators  to  specify  respectively
       sequential  execution  (both  actions  are  executed)  and alternate execution (the second
       action will only be executed if the execution of the first action returns a non-zero error
       status.

       Arguments to actions are an optional suppression time, and then one or more expressions (a
       string is an expression in this context).  Strings appearing as arguments to an action may
       include  the  following  special selectors that will be replaced at the time the action is
       executed.

       %h  Host name(s) that make the left-most top-level expression in the condition true.

       %c  Connection specification string(s) or files for a PCP  tool  to  reach  the  hosts  or
           archives that make the left-most top-level expression in the condition true.

       %i  Instance(s) that make the left-most top-level expression in the condition true.

       %v  One  value  from the left-most top-level expression in the condition for each host and
           instance pair that makes the condition true.

       Note that expansion of the special selectors is done by repeating the whole argument  once
       for each unique binding to any of the qualifying special selectors.  For example if a rule
       were true for the host mumble with instances grunt and snort,  and  for  host  fumble  the
       instance puff makes the rule true, then the action
            ...
            -> shell myscript "Warning: %h:%i busy ";
       will  execute  myscript  with  the  argument  string  "Warning: mumble:grunt busy Warning:
       mumble:snort busy Warning: fumble:puff busy".

       By comparison, if the action
            ...
            -> shell myscript "Warning! busy:" " %h:%i";
       were executed under the same circumstances, then  myscript  would  be  executed  with  the
       argument string "Warning! busy: mumble:grunt mumble:snort fumble:puff".

       The semantics of the expansion of the special selectors leads to a common usage pattern in
       an action, where one argument is a constant (contains no  special  selectors)  the  second
       argument  contains the desired special selectors with minimal separator characters, and an
       optional third argument provides a constant postscript (e.g.  to  terminate  any  argument
       quoting  from  the  first  argument).  If necessary post-processing (e.g. in myscript) can
       provide the necessary enumeration over each unique expansion of the string containing just
       the special selectors.

       For  complex  conditions,  the bindings to these selectors is not obvious.  It is strongly
       recommended that pmie be used in the debugging mode (specify the -W command line option in
       particular) during rule development.

BOOLEAN EXPRESSIONS

       pmie  expressions  that have the semantics of a Boolean, e.g.  foo.bar > 10 or some_inst (
       my.table < 0 ) are assigned the values true or false or unknown.  A value  is  unknown  if
       one  or  more  of  the  underlying metric values is unavailable, e.g.  pmcd(1) on the host
       cannot be contacted, the metric is not  in  the  PCP  archive,  no  values  are  currently
       available,  insufficient  values  have  been fetched to allow a rate converted value to be
       computed or insufficient values have been fetched to instantiate the  required  number  of
       samples in the temporal domain.

       Boolean  operators  follow  the  normal  rules  of  Kleene logic (aka 3-valued logic) when
       combining values that include unknown:

                               ┌────────────┬───────────────────────────┐
                               │            │             B             │
                               │  A and B   ├─────────┬───────┬─────────┤
                               │            │  truefalseunknown │
                               ├──┬─────────┼─────────┼───────┼─────────┤
                               │  │  truetruefalseunknown │
                               │  ├─────────┼─────────┼───────┼─────────┤
                               │A │  falsefalsefalsefalse  │
                               │  ├─────────┼─────────┼───────┼─────────┤
                               │  │ unknownunknownfalseunknown │
                               └──┴─────────┴─────────┴───────┴─────────┘
                                ┌────────────┬──────────────────────────┐
                                │            │            B             │
                                │  A or B    ├──────┬─────────┬─────────┤
                                │            │ truefalseunknown │
                                ├──┬─────────┼──────┼─────────┼─────────┤
                                │  │  truetruetruetrue   │
                                │  ├─────────┼──────┼─────────┼─────────┤
                                │A │  falsetruefalseunknown │
                                │  ├─────────┼──────┼─────────┼─────────┤
                                │  │ unknowntrueunknownunknown │
                                └──┴─────────┴──────┴─────────┴─────────┘
                                          ┌────────┬─────────┐
                                          │   A    │  not A  │
                                          ├────────┼─────────┤
                                          │ truefalse  │
                                          ├────────┼─────────┤
                                          │ falsetrue   │
                                          ├────────┼─────────┤
                                          │unknownunknown │
                                          └────────┴─────────┘

RULESETS

       The ruleset clause is used to define a set of rules and  actions  that  are  evaluated  in
       order  until  some  action is executed, at which point the remaining rules and actions are
       skipped until the ruleset is again scheduled for evaluation.  The keyword else is used  to
       separate  rules.   After  one  or  more  regular rules (with a predicate and an action), a
       ruleset may include an optional
            unknown -> action
       clause, optionally followed by a
            otherwise -> action
       clause.

       If all of the predicates in the rules evaluate to unknown and an unknown clause  has  been
       specified then action associated with the unknown clause will be executed.

       If  no  rule  predicate  is  true  and  the  unknown action is either not specified or not
       executed and an otherwise clause has been specified, then the action associated  with  the
       otherwise clause will be executed.

SCALE FACTORS

       Scale  factors  may  be appended to arithmetic expressions and force linear scaling of the
       value to canonical units.   Simple  scale  factors  are  constructed  from  the  keywords:
       nanosecond,  nanosec,  nsec,  microsecond,  microsec,  usec,  millisecond, millisec, msec,
       second, sec, minute, min, hour, byte,  Kbyte,  Mbyte,  Gbyte,  Tbyte,  count,  Kcount  and
       Mcount, and the operator /, for example ``Kbytes / hour''.

MACROS

       Macros are defined using expressions of the form:

            name = constexpr;

       Where  name  follows  the  normal  rules  for  variables  in  programming  languages, i.e.
       alphabetic optionally followed by alphanumerics.  constexpr must be a constant expression,
       either  a  string  (enclosed  in  double  quotes)  or  an arithmetic expression optionally
       followed by a scale factor.

       Macros are expanded when their name, prefixed by a dollar ($) appears  in  an  expression,
       and macros may be nested within a constexpr string.

       The following reserved macro names are understood.

       minute    Current minute of the hour.

       hour      Current hour of the day, in the range 0 to 23.

       day       Current day of the month, in the range 1 to 31.

       month     Current month of the year, in the range 0 (January) to 11 (December).

       year      Current year.

       day_of_week
                 Current day of the week, in the range 0 (Sunday) to 6 (Saturday).

       delta     Sample interval in effect for this expression.

       Dates  and  times  are  presented in the reporting time zone (see description of -Z and -z
       command line options above).

AUTOMATIC RESTART

       It is often useful for pmie processes to be started and stopped when  the  local  host  is
       booted  or  shutdown, or when they have been detected as no longer running (when they have
       unexpectedly exited for some reason).  Refer to pmie_check(1) for  details  on  automating
       this process.

       Optionally,  each  system running pmcd(1) may also be configured to run a ``primary'' pmie
       instance.  This pmie instance is launched by $PCP_RC_DIR/pmie,  and  is  affected  by  the
       files  $PCP_SYSCONF_DIR/pmie/control,  $PCP_SYSCONF_DIR/pmie/control.d  (use chkconfig(8),
       systemctl(1) or similar platform-specific commands to activate or disable the primary pmie
       instance)  and  $PCP_VAR_DIR/config/pmie/config.default (the default initial configuration
       file for the primary pmie).

       The primary pmie instance is identified by the -P  option.   There  may  be  at  most  one
       ``primary''  pmie  instance  on  each  system.  The primary pmie instance (if any) must be
       running on the same host as the pmcd(1) to which it connects (if any), so the  -h  and  -P
       options are mutually exclusive.

EVENT MONITORING

       It  is common for production systems to be monitored in a central location.  Traditionally
       on UNIX systems this has been performed by the system log facilities - see logger(1),  and
       syslogd(1).   On  Windows,  communication  with  the  system  event log is handled by pcp-
       eventlog(1).

       pmie fits into this model when rules use the syslog  action.   Note  that  if  the  action
       string  begins with -p (priority) and/or -t (tag) then these are extracted from the string
       and treated in the same way as in logger(1) and pcp-eventlog(1).

       However, it is common to have other event monitoring frameworks also, into which  you  may
       wish  to  incorporate performance events from pmie.  You can often use the shell action to
       send events to these frameworks, as they usually provide their  a  program  for  injecting
       events into the framework from external sources.

       A  final  option  is use of the stomp (Streaming Text Oriented Messaging Protocol) action,
       which allows pmie to connect to a central JMS (Java  Messaging  System)  server  and  send
       events to the PMIE topic.  Tools can be written to extract these text messages and present
       them to operations people (via desktop popup windows,  etc).   Use  of  the  stomp  action
       requires  a  stomp configuration file to be setup, which specifies the location of the JMS
       server host, port number, and username/password.

       The format of this file is as follows:

            host=messages.sgi.com   # this is the JMS server (required)
            port=61616              # and its listening here (required)
            timeout=2               # seconds to wait for server (optional)
            username=joe            # (required)
            password=j03ST0MP       # (required)
            topic=PMIE              # JMS topic for pmie messages (optional)

       The  timeout  value  specifies  the  time  (in  seconds)  that  pmie   should   wait   for
       acknowledgements  from  the  JMS  server after sending a message (as required by the STOMP
       protocol).  Note that on startup, pmie will wait indefinitely for a connection,  and  will
       not  begin rule evaluation until that initial connection has been established.  Should the
       connection to the JMS server be lost at any time while pmie is running, pmie will  attempt
       to reconnect on each subsequent truthful evaluation of a rule with a stomp action, but not
       more than once per minute.  This is to avoid contributing to network congestion.  In  this
       situation, where the STOMP connection to the JMS server has been severed, the stomp action
       will return a non-zero error value.

DIFFERENCES IN HOST AND ARCHIVE MODES

       When running in host mode, the delta interval for each rule determines a  real-time  delay
       between rule evaluation, so pmie spends most if its time sleeping and waiting for the next
       scheduled rule evaluation.

       When running in archive mode, pmie uses the delta interval for each rule to determine  how
       frequently  the  rules  are evaluated against the archive data, but unlike host mode there
       are no real-time delays as the archive is ``replayed'' as fast as possible.

       In archive mode when a rule predicate evaluates true then the action is modified, so  that
       rather  than  posting  to  syslog or raising a visible alarm or running a shell command or
       sending a stomp message, pmie prints the name  of  the  action,  the  timestamp  from  the
       archive  when  the  rule predicate triggering the action was true and all of the arguments
       that would have been passed to the real action in host mode.

       For example, given the rule:
            delta = 10 sec;
            kernel.all.nprocs > 10 * hinv.ncpu -> print "lotsaprocs:" " %v";
       when run against an archive, the output appears as:
            print Mon Sep  4 00:10:21 2017: lotsaprocs: 1292
            print Mon Sep  4 00:10:31 2017: lotsaprocs: 1294
            print Mon Sep  4 00:10:41 2017: lotsaprocs: 1291
            ...

       The rationale is that the context in which the action would have been  executed  (in  host
       mode)  was  at a time in the past and the possibly on a different host (if the archive was
       collected from one host, but pmie is being run on a different host).  So  flooding  syslog
       with  misleading  messages  or  an avalanche visual alarms or a lot of STOMP messages or a
       shell command that might not even work on the host  where  pmie  is  being  run,  are  all
       examples  of  ``badness''  to  be  avoided.  Rather the output is text in a regular format
       suitable for post-processing with a range of filters and performance analysis tools.

       The output format can be changed using the -o option which consists of literal  characters
       with the following embedded ``meta-field'' tokens:

       %a  The name of the action, e.g.  print, syslog, etc.

       %d  The date and time in ctime(3) format when the action would have been executed.

       %f  The  name of the configuration file containing the action being executed, else <stdin>
           if the rules were read from standard input.

       %l  The (approximate) line number in the configuration file for the action being executed.

       %m  The message component of the action.

       %u  The date and time when the action would have been executed in extended ctime(3) format
           with microsecond precision for the time.

       %%  A literal percent character.

       The default output format is equivalent to a format of %a %d: %m.

SIGNALS

       If pmie is sent a SIGHUP signal, the logfile will be closed, unlinked and re-opened.  This
       is used by pmie_daily(1) to achieve nightly log rotation.

       Most of the time pmie is sleeping, waiting until  the  next  set  of  rules  needs  to  be
       evaluated.  Sending pmie a SIGUSR1 signal will cause the details for the next set of rules
       to be dumped on logfile, including how long  the  current  sleep  is  and  how  much  time
       remains.  The scheduling of rules is not changed by this action.

HOSTNAME CHANGES

       The hostname of the PMCD that is providing metrics to pmie is used in several ways.

       PMCD's  hostname  is  user  internally to provide a value for the %h substitutions in rule
       action strings.

       For pmie instances using a local PMCD that are launched and managed by  pmie_check(1)  and
       pmie_daily(1),  (or  the systemd(1) or cron(8) services that use these scripts), the local
       hostname may also be used to construct the name of a directory where the pmie logs for one
       host are stored, e.g. $PCP_LOG_DIR/pmie/<hostname>.

       The hostname of the PMCD host may change during boot time when the system transitions from
       a temporary hostname to a  persistent  hostname,  or  by  explicit  administrative  action
       anytime  after  the  system  has  been  booted.   When this happens, pmie may need to take
       special action, specifically if the pmie  instance  was  launched  from  pmie_check(1)  or
       pmie_daily(1), then pmie must exit.  Under normal circumstances systemd(1) or cron(8) will
       launch a new pmie shortly thereafter, and this new pmie instance will be operating in  the
       context of the new hostname for the host where PMCD is running.

BUGS

       The  lexical  scanner  and  parser  will  attempt  to  recover after an error in the input
       expressions.  Parsing resumes after skipping input up to the next semi-colon (;),  however
       during  this  skipping  process  the  scanner  is  ignorant of comments and strings, so an
       embedded semi-colon may cause parsing to resume at an unexpected place.  This behavior  is
       largely  benign, as until the initial syntax error is corrected, pmie will not attempt any
       expression evaluation.

FILES

       $PCP_DEMOS_DIR/pmie/*
            annotated example rules

       $PCP_VAR_DIR/pmns/*
            default PMNS specification files

       $PCP_TMP_DIR/pmie
            pmie maintains files in this directory to identify the running pmie instances and  to
            export  runtime  information  about  each instance - this data forms the basis of the
            pmcd.pmie performance metrics

       $PCP_PMIECONTROL_PATH
            the default set of pmie instances to start at boot time - refer to pmie_check(1)  for
            details

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).

       When executing shell actions, pmie overrides two  variables  -  IFS  and  PATH  -  in  the
       environment of the child process.  IFS is set to "\t\n".  The PATH is set to a combination
       of  a  default  path  for  all  platforms  ("/usr/sbin:/sbin:/usr/bin:/bin")  and  several
       configurable  components.   These  are  (in this order): $PCP_BIN_DIR, $PCP_BINADM_DIR and
       $PCP_PLATFORM_PATHS.

       When executing popup alarm actions, pmie will use the value of $PCP_XCONFIRM_PROG  as  the
       visual  notification  program  to  run.   This  is typically set to pmconfirm(1), a cross-
       platform dialog box.

UNIX SEE ALSO

       logger(1).

WINDOWS SEE ALSO

       pcp-eventlog(1).

SEE ALSO

       PCPIntro(1), pmcd(1), pmconfirm(1), pmie_check(1), pmieconf(1), pmie_daily(1),  pminfo(1),
       pmlogdump(1),   pmlogger(1),   pmval(1),   systemd(1),  ctime(3),  PMAPI(3),  pcp.conf(5),
       pcp.env(5) and PMNS(5).

USER GUIDE

       For a more complete description of the pmie language, refer to  the  Performance  Co-Pilot
       Users and Administrators Guide.  This is available online from:
           https://pcp.readthedocs.io/en/latest/UAG/PerformanceMetricsInferenceEngine.html