Measure time spent in each target of a Makefile

问题:

Is there a way to echo the (system, user, real) time spent in each target of a Makefile recursively when I do make all?

I'd like to benchmark the compilation of a project in a more granular way than just time make all. Ideally, it would echo a tree of the executed target, each one with the time spent in all its dependencies. It'd be great also if it could work with -j (parallel make). And by the way my Makefile is non-recursive (doesn't spawn another make instance for each main targets).

Thanks!

回答1:

Gnu Make uses the $(SHELL) variable to execute commands in the targets.

By default it is set to /bin/sh.

You can set this variable to a script that will execute the command given with the "time" command. Something like this:

In your makefile specify the SHELL variable, somewhere at the top:

SHELL = ./report_time.sh

and in the file ./report_time.sh:

#!/bin/sh
shift  # get rid of the '-c' supplied by make.
time sh -c "$*"

The replace the 'sh' command with the original SHELL specified in the Makefile if any.

This will report the timings.

However This will not tell you what target the report_time.sh script is running. One solution for this is to prepend the target name ($@) in each target entry in the makefile so that it will be passed to the report_time.sh script as well.

回答2:

remake --profile is a drop-in replacement for make. It generates a target call tree in a callgrind format.