Use alloca to address memory layout effects

bheisler / criterion.rs

Statistics-driven benchmarking library for Rust

Apache License 2.0

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Open PSeitz opened 10 months ago

PSeitz commented 10 months ago

replace collect with Vec::reserve the iter collect pollutes the call stack (10 levels of calls)
offset tests with alloca As mentioned in #334, randomness in memory layout has a huge impact on the bench results. When I benchmark with criterion it's not uncommon to see effects of +-30%. Tests seem much more stable with alloca, there's still random 6% jumps in one test I've been running.

Adresses #334

FilipAndersson245 commented 6 months ago

Seems quite straightforward and if this helps in reducing random changes between runs I'm all for this.

waywardmonkeys commented 2 months ago

@PSeitz Thanks for your contribution! Are you interested in updating this PR for the review comments or should we take it on?