NAME

       pmwtf - compares archives and report significant differences

SYNOPSIS

       pmwtf  [-dz]  [-p  precision]  [-q  thres]  [-S starttime] [-T endtime] [-B starttime] [-E
       endtime] [-x metric] [-X file] [-Z timezone] archive1 [archive2]

DESCRIPTION

       pmwtf compares the average values for every metric in either one or  two  archives,  in  a
       given  time  window,  for  changes  that  are  likely to be of interest when searching for
       performance regressions.

       The archive log has the base name archive and must  have  been  previously  created  using
       pmlogger(1).   The  pmlogsummary(1)  utility is used to obtain the average values used for
       comparison.

       There are two sorts of invocation of the tool: with either one or two archives.

       In the first case, the only sensible command line requires use of  all  four  time  window
       arguments.    These  are  specified  using  the  same  time  window  format  described  in
       PCPIntro(1), and are -S and -T for the start and end times of the  first  time  window  of
       interest  in  the  archive,  and  -B and -E for the start and end times of the second time
       window of interest.

       In the second case, with two archives, the -B and -E options might be  unnecessary.   This
       might  be  the  case,  for example, when comparing the same time window of two consecutive
       days (usually two separate archives), or a time window on the same day of different weeks.

       In either case, pmwtf produces a sorted summary of those metrics in the  specified  window
       whose  values  have deviated the most from a minimal threshold.  The level of deviation is
       calculated by dividing the average value of each metric in both logs, and then calculating
       whether  the ratio falls outside of a range considered normal.  This ratio can be adjusted
       using the -q option, and by default it is 2 (i.e. report all metrics with  average  values
       that  have  more  than doubled in the two time windows or more than halved in the two time
       windows).

       Should any metrics be present in one window but missing from the other, a diagnostic  will
       be displayed listing each missing metric and the archive from which it was missing.

       The  remaining  options  control  the  specific  information to be reported.  Metrics with
       counter semantics are converted to rates before being evaluated.

       -p   Print all floating point numbers with precision digits after the decimal place.

       -x   Compare each metric in each archive in the time windows specified to a given egrep(1)
            pattern, excluding those that match from the report output.

       -X   Allows a file to be specified which containing egrep(1) patterns which are applied to
            the metric names to optionally exclude some from the report.

       -z   Use the local timezone from the given archives.

       -Z   Changes the timezone in  the  archive  labels  to  timezone  in  the  format  of  the
            environment variable TZ as described in environ(5).

FILES

       $PCP_LOG_DIR/pmlogger/hostname
                 Default   directory  for  PCP  archives  containing  performance  metric  values
                 collected from the host hostname.

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), pmlogger(1), pmlogsummary(1), egrep(1), pcp.conf(5) and pcp.env(5).