Comparison between Scons and Waf on no-op build times
(targets are up-to-date).

The previous version of this document is available at:
http://freehackers.org/~tnagy/bench2.txt

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The values measured below are the runtime in a folder that
contains all built targets up-to-date.

They represent more or less the time to wait for the
build tool before a file that was modified starts compiling

Waf and Scons use a similar signature-based scheme to decide
if a target needs to be rebuilt:
   file md5 + command-line + other dependencies

The following script was used:
   http://freehackers.org/~tnagy/genbench.py
with the following command-line:
   ./genbench.py /tmp/build 50 100 15 5

The benchmark generates 50 static libraries using 100 cpp classes, 
with 15 includes from the same folder and 5 includes from
different folders in each header file, this makes approximately
22 header dependencies for each cpp file, in 5000 cpp files

The time values were measured using "time"
The hardware is a laptop with 512Mb of ram and a pentium 4
The same operating system was used (OpenSuse 10.2)

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Waf 1.4.0
available as a single script http://freehackers.org/~tnagy/waf (93KB)
or as source http://freehackers.org/~tnagy/waf-1.4.0.tar.bz2

real    0m3.485s
user    0m3.304s
sys     0m0.164s

real    0m3.444s
user    0m3.212s
sys     0m0.216s

real    0m3.469s
user    0m3.296s
sys     0m0.156s

real    0m3.492s
user    0m3.324s
sys     0m0.136s

Using scons 0.98.1 (scons: `.' is up to date.)

real    1m3.955s
user    1m2.504s
sys     0m0.984s

real    1m3.140s
user    1m1.960s
sys     0m0.892s

real    1m4.649s
user    1m2.792s
sys     0m1.012s

Waf is about 18 times faster than Scons.

Using options that degrade build accuracy:
time scons --implicit-deps-unchanged --max-drift=1

real    0m41.375s
user    0m40.803s
sys     0m0.420s

Waf is only about 12 times faster.

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Comparison against GNU/Make (recursive version)

Waf runtimes are close to those of make, using "time make":

real    0m3.537s
user    0m2.432s
sys     0m0.816s

real    0m3.474s
user    0m2.436s
sys     0m0.792s

By suppressing the make output (not the default), a speedup can be obtained:
"time make>/dev/null"

real    0m3.011s
user    0m2.256s
sys     0m0.732s

real    0m3.003s
user    0m2.252s
sys     0m0.744s

Unlike Waf or Scons, Make does only track timestamps (no task signatures,
and no hashing of the files using md5).