Commit 3a3beae8 authored by Jiri Olsa's avatar Jiri Olsa Committed by Arnaldo Carvalho de Melo

perf diff: Update perf diff documentation for multiple data comparison

Updating perf diff documentation to include multiple perf data files
comparison.
Signed-off-by: default avatarJiri Olsa <jolsa@redhat.com>
Reviewed-by: default avatarNamhyung Kim <namhyung@kernel.org>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/n/tip-tr6su3wfm20k2m5npjggyvtw@git.kernel.orgSigned-off-by: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 22aeb7f5
...@@ -3,17 +3,17 @@ perf-diff(1) ...@@ -3,17 +3,17 @@ perf-diff(1)
NAME NAME
---- ----
perf-diff - Read two perf.data files and display the differential profile perf-diff - Read perf.data files and display the differential profile
SYNOPSIS SYNOPSIS
-------- --------
[verse] [verse]
'perf diff' [oldfile] [newfile] 'perf diff' [baseline file] [data file1] [[data file2] ... ]
DESCRIPTION DESCRIPTION
----------- -----------
This command displays the performance difference amongst two perf.data files This command displays the performance difference amongst two or more perf.data
captured via perf record. files captured via perf record.
If no parameters are passed it will assume perf.data.old and perf.data. If no parameters are passed it will assume perf.data.old and perf.data.
...@@ -87,6 +87,59 @@ OPTIONS ...@@ -87,6 +87,59 @@ OPTIONS
--formula:: --formula::
Show formula for given computation. Show formula for given computation.
COMPARISON
----------
The comparison is governed by the baseline file. The baseline perf.data
file is iterated for samples. All other perf.data files specified on
the command line are searched for the baseline sample pair. If the pair
is found, specified computation is made and result is displayed.
All samples from non-baseline perf.data files, that do not match any
baseline entry, are displayed with empty space within baseline column
and possible computation results (delta) in their related column.
Example files samples:
- file A with samples f1, f2, f3, f4, f6
- file B with samples f2, f4, f5
- file C with samples f1, f2, f5
Example output:
x - computation takes place for pair
b - baseline sample percentage
- perf diff A B C
baseline/A compute/B compute/C samples
---------------------------------------
b x f1
b x x f2
b f3
b x f4
b f6
x x f5
- perf diff B A C
baseline/B compute/A compute/C samples
---------------------------------------
b x x f2
b x f4
b x f5
x x f1
x f3
x f6
- perf diff C B A
baseline/C compute/B compute/A samples
---------------------------------------
b x f1
b x x f2
b x f5
x f3
x x f4
x f6
COMPARISON METHODS COMPARISON METHODS
------------------ ------------------
delta delta
...@@ -96,7 +149,7 @@ If specified the 'Delta' column is displayed with value 'd' computed as: ...@@ -96,7 +149,7 @@ If specified the 'Delta' column is displayed with value 'd' computed as:
d = A->period_percent - B->period_percent d = A->period_percent - B->period_percent
with: with:
- A/B being matching hist entry from first/second file specified - A/B being matching hist entry from data/baseline file specified
(or perf.data/perf.data.old) respectively. (or perf.data/perf.data.old) respectively.
- period_percent being the % of the hist entry period value within - period_percent being the % of the hist entry period value within
...@@ -109,24 +162,26 @@ If specified the 'Ratio' column is displayed with value 'r' computed as: ...@@ -109,24 +162,26 @@ If specified the 'Ratio' column is displayed with value 'r' computed as:
r = A->period / B->period r = A->period / B->period
with: with:
- A/B being matching hist entry from first/second file specified - A/B being matching hist entry from data/baseline file specified
(or perf.data/perf.data.old) respectively. (or perf.data/perf.data.old) respectively.
- period being the hist entry period value - period being the hist entry period value
wdiff wdiff:WEIGHT-B,WEIGHT-A
~~~~~ ~~~~~~~~~~~~~~~~~~~~~~~
If specified the 'Weighted diff' column is displayed with value 'd' computed as: If specified the 'Weighted diff' column is displayed with value 'd' computed as:
d = B->period * WEIGHT-A - A->period * WEIGHT-B d = B->period * WEIGHT-A - A->period * WEIGHT-B
- A/B being matching hist entry from first/second file specified - A/B being matching hist entry from data/baseline file specified
(or perf.data/perf.data.old) respectively. (or perf.data/perf.data.old) respectively.
- period being the hist entry period value - period being the hist entry period value
- WEIGHT-A/WEIGHT-B being user suplied weights in the the '-c' option - WEIGHT-A/WEIGHT-B being user suplied weights in the the '-c' option
behind ':' separator like '-c wdiff:1,2'. behind ':' separator like '-c wdiff:1,2'.
- WIEGHT-A being the weight of the data file
- WIEGHT-B being the weight of the baseline data file
SEE ALSO SEE ALSO
-------- --------
......
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