Bit of a random one coming up…
I needed to get an measure of the difference in performance between Perl and Java for a simple client application, so I wrote the traditional ‘Hello World’ app in both and ran a bunch of executions averaging over the time from start to end of execution. The net result:
Perl is around 34 times faster than Java.
Really? I thought Java was supposed to be fast? In fact, Dhananjay Nene talked about how comparatively fast a selection of languages – including Java – were on his blog, and cwilbur ‘s comments suggest that in that experiment:
Java is around 100 times faster than Perl.
So how can these two conflicting results both be true? I’m sure you’ve already figured it out, but I’m going to tell you anyway.
Java code takes hundreds of milliseconds to start up, because Java code runs in the Java Virtual Machine which needs a little time to get itself ready before your code can run. Once it’s up, however, you can get performance close to (or even better than, in reality) that of typical C++. [edit – originally no supporting evidence was offered. My sources for this statement on Java vs. C++ are resources like http://scribblethink.org/Computer/javaCbenchmark.html like https://www.theserverside.com/opinion/Is-Java-slow-Compared-to-C-its-faster-than-you-think. Personally, I have very limited hobbyist experience of C and C++ many years out of date now]
On the other hand, Perl doesn’t need that environment and so can start faster but trades off more overhead at runtime, meaning slower running performance.
Just goes to show, application performance is another area where there’s no one right answer – it’s about choosing the right tool for the job – I don’t think there’s any way round these performance characteristics without cheating.