12.3 Running the profiler

The profiler has two distinct modes. You can use both in the same session, but not at the same time.

The macro profile simply profiles all processes while a body of code is run, as described in 12.3.1 Using the macro profile. Start profiling this way if you don't see a need to use the alternate mode.

Alternatively the functions start-profiling, stop-profiling and set-process-profiling offer programmatic control over when profiling occurs and which processes are profiled. This is described in 12.3.2 Programmatic control of profiling.

The function do-profiling is a convenience function which allows you to profile multiple threads using start-profiling and stop-profiling.

12.3.1 Using the macro profile

To profile your Lisp forms enter:

(profile <forms>)

This evaluates the forms as an implicit progn and prints the results, according to the parameters established by set-up-profiler.

Note: you cannot use profile (or the graphical Profiler tool) after a call to start-profiling and before a call to stop-profiling with print t, because the two profiling modes are incompatible.

12.3.2 Programmatic control of profiling

Your program can control profiling. This is useful when you want to profile only a part of the program.

In your program, call start-profiling start collecting profiling information. Call stop-profiling with print nil to temporarily stop collecting, or call stop-profiling with print t to stop collecting and print the results. At any point you can call set-process-profiling to modify the set of processes for which profiling information is being (or will be) collected.

For example:

;; start profiling, current process only
(start-profiling :processes :current)
(do-interesting-work)
;; temporarily suspend profiling
(stop-profiling :print nil)
(do-uninteresting-work)
;; resume profiling
(start-profiling :initialize nil)
(do-more-interesting-work)
;; now, all processes are interesting
(set-process-profiling :set :all)
(do-some-more-interesting-work)
;; stop profiling and print the results
(stop-profiling)

Note: you cannot call start-profiling inside the scope of the macro profile or while the graphical Profiler is profiling, because the two profiling modes are incompatible.