| perf-diff(1) |
| ============ |
| |
| NAME |
| ---- |
| perf-diff - Read two perf.data files and display the differential profile |
| |
| SYNOPSIS |
| -------- |
| [verse] |
| '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 |
| ------- |
| -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 ALSO |
| -------- |
| linkperf:perf-record[1] |
