The following are examples of js_cputime.d. This script traces the on-CPU time of JavaScript functions and prints a report. Here it traces the example program, Code/JavaScript/func_clock.html # js_cputime.d Tracing... Hit Ctrl-C to end. ^C Count, FILE TYPE NAME COUNT func_clock.html func func_a 5 func_clock.html func func_b 5 func_clock.html func func_c 5 func_clock.html func setTimeout 5 func_clock.html func start 5 func_clock.html obj-new Date 5 func_clock.html func getElementById 20 - total - 50 Elapsed times (us), FILE TYPE NAME TOTAL - total - 37 func_clock.html obj-new Date 37 Exclusive function on-CPU times (us), FILE TYPE NAME TOTAL func_clock.html func setTimeout 316 func_clock.html func getElementById 588 func_clock.html func start 4734 func_clock.html func func_a 83465 func_clock.html func func_b 166613 func_clock.html func func_c 247683 - total - 503402 Inclusive function on-CPU times (us), FILE TYPE NAME TOTAL func_clock.html func setTimeout 316 func_clock.html func getElementById 588 func_clock.html func func_c 247872 func_clock.html func func_b 414601 func_clock.html func func_a 498142 func_clock.html func start 503439 You can see the results are printed in four sections. The first section reports how many times each subroutine was called, and it's type. The second section reports on the on-CPU time of anything that was not of type "func", in this case the only elements reported here are Date obj-new. The exclusive subroutine on-CPU times shows, amongst other results, that func_a spent around 83,000 microseconds on-CPU. This time excludes time spent in other subroutines. The inclusive subroutine on-CPU times show that func_a spent around 0.5 seconds on-CPU. This includes the time spent in other subroutines called. These on-CPU times are the time the thread spent running on a CPU, from when the subroutine began to when it completed. This does not include time spent off-CPU time such as sleeping for I/O or waiting for scheduling. On-CPU times are useful for showing who is causing the CPUs to be busy. See Notes/ALLoncpu_notes.txt for more details. Also see Notes/ALLexclusive_notes.txt and Notes/ALLinclusive_notes.txt for a detailed explanation of exclusive vs inclusive subroutine time.