PERF-DIFF(1) perf Manual PERF-DIFF(1)NAMEperf-diff - Read two perf.data files and display the differential
profile
SYNOPSIS
perf diff [oldfile] [newfile]
DESCRIPTION
This command displays the performance difference amongst two perf.data
files captured via perf record.
If no parameters are passed it will assume perf.data.old and perf.data.
The differential profile is displayed only for events matching both
specified perf.data files.
OPTIONS-M, --displacement
Show position displacement relative to baseline.
-D, --dump-raw-trace
Dump raw trace in ASCII.
-m, --modules
Load module symbols. WARNING: use only with -k and LIVE kernel
-d, --dsos=
Only consider symbols in these dsos. CSV that understands
file://filename entries.
-C, --comms=
Only consider symbols in these comms. CSV that understands
file://filename entries.
-S, --symbols=
Only consider these symbols. CSV that understands file://filename
entries.
-s, --sort=
Sort by key(s): pid, comm, dso, symbol.
-t, --field-separator=
Use a special separator character and don’t pad with spaces,
replacing all occurrences of this separator in symbol names (and
other output) with a . character, that thus it’s the only non
valid separator.
-v, --verbose
Be verbose, for instance, show the raw counts in addition to the
diff.
-f, --force
Don’t complain, do it.
--symfs=<directory>
Look for files with symbols relative to this directory.
-b, --baseline-only
Show only items with match in baseline.
-c, --compute
Differential computation selection - delta,ratio,wdiff (default is
delta). If + is specified as a first character, the output is
sorted based on the computation results. See COMPARISON METHODS
section for more info.
-p, --period
Show period values for both compared hist entries.
-F, --formula
Show formula for given computation.
COMPARISON METHODS
delta
If specified the Delta column is displayed with value d computed as:
d = A->period_percent - B->period_percent
with: - A/B being matching hist entry from first/second file specified
(or perf.data/perf.data.old) respectively.
· period_percent being the % of the hist entry period value within
single data file
ratio
If specified the Ratio column is displayed with value r computed as:
r = A->period / B->period
with: - A/B being matching hist entry from first/second file specified
(or perf.data/perf.data.old) respectively.
· period being the hist entry period value
wdiff
If specified the Weighted diff column is displayed with value d
computed as:
d = B->period * WEIGHT-A - A->period * WEIGHT-B
· A/B being matching hist entry from first/second file specified (or
perf.data/perf.data.old) respectively.
· period being the hist entry period value
· WEIGHT-A/WEIGHT-B being user suplied weights in the the -c option
behind : separator like -c wdiff:1,2.
SEE ALSOperf-record(1)perf 11/21/2013 PERF-DIFF(1)
