| @node Profiling of program phases |
| @section Profiling of program phases |
| |
| The module @samp{timevar} provides a simple self-profiling facility, |
| based on timers. |
| |
| @smallexample |
| Execution times (seconds) |
| read : 0.09 (19%) usr 0.08 (80%) sys 0.09 (18%) wall |
| read: scan : 0.04 ( 9%) usr 0.08 (80%) sys 0.12 (26%) wall |
| read: parse : 0.05 (10%) usr 0.00 ( 0%) sys 0.05 (10%) wall |
| work : 0.33 (70%) usr 0.00 ( 0%) sys 0.35 (71%) wall |
| work: phase 1 : 0.30 (64%) usr 0.00 ( 0%) sys 0.30 (64%) wall |
| work: phase 2 : 0.13 (28%) usr 0.00 ( 0%) sys 0.14 (29%) wall |
| output : 0.04 ( 9%) usr 0.02 (20%) sys 0.04 ( 8%) wall |
| total time : 0.47 0.10 0.49 |
| @end smallexample |
| |
| To set up @code{timevar}, copy the stub file |
| @file{gnulib/lib/timevar.def} next to where @file{timevar.h} and |
| @file{timevar.c} were imported in your project, and define your timers |
| there. For instance: |
| |
| @smallexample |
| /* The total execution time. Mandatory. */ |
| DEFTIMEVAR (tv_total, "total time") |
| |
| /* Examples. */ |
| DEFTIMEVAR (tv_read, "read") |
| DEFTIMEVAR (tv_work, "work") |
| DEFTIMEVAR (tv_work_1, "work: phase 1") |
| DEFTIMEVAR (tv_work_2, "work: phase 2") |
| DEFTIMEVAR (tv_output, "output") |
| @end smallexample |
| |
| Do not remove @code{tv_total}, it is mandatory. You may change its |
| associated string. |
| |
| @sp 1 |
| |
| Use @code{timevar_push}/@code{timevar_pop} to start/stop timers, as in |
| the following example. |
| |
| @smallexample |
| #include <config.h> |
| #include "timevar.h" |
| |
| #include <stdio.h> |
| #include "read.h" |
| #include "work.h" |
| #include "output.h" |
| |
| int |
| main (void) |
| @{ |
| timevar_enabled = true; |
| timevar_init (); |
| timevar_start (tv_total); |
| |
| timevar_push (tv_read); |
| reader (); |
| timevar_pop (tv_read); |
| |
| timevar_push (tv_work); |
| work (); |
| timevar_pop (tv_work); |
| |
| timevar_push (tv_output); |
| output (); |
| timevar_pop (tv_output); |
| |
| timevar_stop (tv_total); |
| timevar_print (stderr); |
| @} |
| @end smallexample |
| |
| @noindent |
| with, for instance, in @file{work.c} |
| |
| @smallexample |
| #include <config.h> |
| #include "work.h" |
| |
| void |
| work (void) |
| @{ |
| timevar_push (tv_work_phase1); |
| work1 (); |
| timevar_pop (tv_work_phase1); |
| |
| timevar_push (tv_work_phase2); |
| work2 (); |
| timevar_pop (tv_work_phase2); |
| @} |
| @end smallexample |