diff options
Diffstat (limited to 'tools/perf/Documentation/perf-diff.txt')
| -rw-r--r-- | tools/perf/Documentation/perf-diff.txt | 88 |
1 files changed, 83 insertions, 5 deletions
diff --git a/tools/perf/Documentation/perf-diff.txt b/tools/perf/Documentation/perf-diff.txt index a79c84ae61aa..58efab72d2e5 100644 --- a/tools/perf/Documentation/perf-diff.txt +++ b/tools/perf/Documentation/perf-diff.txt @@ -75,7 +75,7 @@ OPTIONS -q:: --quiet:: - Do not show any message. (Suppress -v) + Do not show any warnings or messages. (Suppress -v) -f:: --force:: @@ -90,9 +90,15 @@ OPTIONS -c:: --compute:: - Differential computation selection - delta, ratio, wdiff, delta-abs - (default is delta-abs). Default can be changed using diff.compute - config option. See COMPARISON METHODS section for more info. + Differential computation selection - delta, ratio, wdiff, cycles, + delta-abs (default is delta-abs). Default can be changed using + diff.compute config option. See COMPARISON METHODS section for + more info. + +--cycles-hist:: + Report a histogram and the standard deviation for cycles data. + It can help us to judge if the reported cycles data is noisy or + not. This option should be used with '-c cycles'. -p:: --period:: @@ -118,6 +124,68 @@ OPTIONS sum of shown entries will be always 100%. "absolute" means it retains the original value before and after the filter is applied. +--time:: + Analyze samples within given time window. It supports time + percent with multiple time ranges. Time string is 'a%/n,b%/m,...' + or 'a%-b%,c%-%d,...'. + + For example: + + Select the second 10% time slice to diff: + + perf diff --time 10%/2 + + Select from 0% to 10% time slice to diff: + + perf diff --time 0%-10% + + Select the first and the second 10% time slices to diff: + + perf diff --time 10%/1,10%/2 + + Select from 0% to 10% and 30% to 40% slices to diff: + + perf diff --time 0%-10%,30%-40% + + It also supports analyzing samples within a given time window + <start>,<stop>. Times have the format seconds.nanoseconds. If 'start' + is not given (i.e. time string is ',x.y') then analysis starts at + the beginning of the file. If stop time is not given (i.e. time + string is 'x.y,') then analysis goes to the end of the file. + Multiple ranges can be separated by spaces, which requires the argument + to be quoted e.g. --time "1234.567,1234.789 1235," + Time string is'a1.b1,c1.d1:a2.b2,c2.d2'. Use ':' to separate timestamps + for different perf.data files. + + For example, we get the timestamp information from 'perf script'. + + perf script -i perf.data.old + mgen 13940 [000] 3946.361400: ... + + perf script -i perf.data + mgen 13940 [000] 3971.150589 ... + + perf diff --time 3946.361400,:3971.150589, + + It analyzes the perf.data.old from the timestamp 3946.361400 to + the end of perf.data.old and analyzes the perf.data from the + timestamp 3971.150589 to the end of perf.data. + +--cpu:: Only diff samples for the list of CPUs provided. Multiple CPUs can + be provided as a comma-separated list with no space: 0,1. Ranges of + CPUs are specified with -: 0-2. Default is to report samples on all + CPUs. + +--pid=:: + Only diff samples for given process ID (comma separated list). + +--tid=:: + Only diff samples for given thread ID (comma separated list). + +--stream:: + Enable hot streams comparison. Stream can be a callchain which is + aggregated by the branch records from samples. + COMPARISON ---------- The comparison is governed by the baseline file. The baseline perf.data @@ -217,11 +285,21 @@ If specified the 'Weighted diff' column is displayed with value 'd' computed as: - period being the hist entry period value - - WEIGHT-A/WEIGHT-B being user supplied weights in the the '-c' option + - WEIGHT-A/WEIGHT-B being user supplied weights in the '-c' option behind ':' separator like '-c wdiff:1,2'. - WEIGHT-A being the weight of the data file - WEIGHT-B being the weight of the baseline data file +cycles +~~~~~~ +If specified the '[Program Block Range] Cycles Diff' column is displayed. +It displays the cycles difference of same program basic block amongst +two perf.data. The program basic block is the code between two branches. + +'[Program Block Range]' indicates the range of a program basic block. +Source line is reported if it can be found otherwise uses symbol+offset +instead. + SEE ALSO -------- linkperf:perf-record[1], linkperf:perf-report[1] |