Favorite benchmarking tools

High Definition

At the Dragon Propulsion Laboratory, we are partial to using the simplest tool that will do the job at hand – particularly when dealing with the inherent complexity that performance measurement (and tuning) brings to the table. Yet that same complexity often requires advanced tooling to resolve the riddles posed by performance questions. I will examine my current benchmarking tool favorites from the simplest to the more sophisticated.

Tempus Fugit

The benchmark archetype is time: simple, easy to use, and well understood by most users. In its purest form, time takes a command as a parameter and times its execution in the real world (real), as well as how much CPU time was allocated in user and kernel (sys) modes:

$  time sleep 1
real   0m1.004s
user  0m0.002s
sys   0m0.001s

What not everyone knows is that the default time command is actually one of the bash-builtins [1]:

$ type time
time is a shell keyword
$ which time
/usr/bin/time

There is time, and then there is GNU time [2]. The standalone binary version sports a few additional capabilities, the most noteworthy being its ability to measure page faults and swapping activity by the tested binary:

$ /usr/bin/time gcc test.c -o test
0.03user 0.01system 0:00.05elapsed 98%CPU (0avgtext+0avgdata 20564maxresident)k
0inputs+40outputs (0major+4475minor)pagefaults 0swaps

The sixth Dojo was dedicated to GNU time's amazing capabilities, and I invite you to read up in your prized archive of ADMIN back issues [3]. Table 1 sums up the capabilities of this versatile tool,

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