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Postings from September 2012
Steffen Schwigon commented in another thread that it's very hard to find benchmarks that are designed to behave like typical programs. It's very easy to write a benchmark for a particular thing, and it's fairly easy to get such a beast to show that a particular change will speed that benchmark up. But Whilst such a benchmark will show you the behaviour of a specific feature in isolation, they typically don't actually represent realistic code. They usually don't throw enough data around or create enough objects to start to stress the memory subsystems. And they don't do enough different things to thrash any CPU instruction cache. So It's much harder to show whether a particular change slows everything else down meaningfully enough to not be worth it. So Does anyone have any code to use as benchmarks that behave like "typical" Perl programs? This for the purpose of benchmarking the perl interpreter and assessing the viability of potential optimisations, particularly optimisations that involve trade offs that are going to make some cases slower. I'm pretty sure that any "functionality" test suite is not going to make a good "load test" performance benchmark, because it's a) trying to test corner cases, not common cases b) trying to do this as efficiently as possible and certainly not trying to do something that lasts for 20 to 30 seconds for the sake of lasting for 20-30 seconds. Needs to do realistic things on a big enough scale to stress a typical system. Needs to avoid external library dependencies, or particular system specifics. Needs to be constrained by CPU or RAM, not blocking on an I/O device. Preferably needs to be doing something that Perl is typically used for. Preferably needs to avoid being too Perl version specific. Preferably needs to avoid being a maintenance headache itself. Nicholas ClarkThread Next