PMWTF(1)PMWTF(1)NAMEpmwtf - compares archives and report significant differences
SYNOPSISpmwtf [-dz] [-p precision] [-q thres] [-S starttime] [-T endtime] [-B
starttime] [-E endtime] [-x metric] [-X file] [-Z timezone] archive1
[archive2]
DESCRIPTIONpmwtf 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 ar‐
chives), 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 aver‐
age 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 ar‐
chive 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 for‐
mat 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 ALSOPCPIntro(1), pmlogger(1), pmlogsummary(1), egrep(1), pcp.conf(5) and
pcp.env(5).
Performance Co-Pilot PCP PMWTF(1)
