alt Hacker NewsThe mistake there is to point it at code to figure out performance optimizations.
The place to find them would be performance profiles, query plans, telemetry. The guidance for perf still applies, measure before and after change.
The issue is that the code often does not contain the information to do a perf optimization. Eg. you can't tell your cache size, the volumes of data in your DB or the latency of your network through just the text. Should you provide this context, you can get better results.
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> The place to find them would be performance profiles, query plans, telemetry.
Tbh, once this information is available (which is the tricky part), in 99% of cases there's really no AI needed to analyze the data, since the 'low hanging fruits' will usually stand out anyway. And once you get into the area where optimization hotspots are no longer obvious, you're already deep in the diminishing returns area and optimizations for one use case or hardware configuration may degrade performance on others. That's my experience anyway.
It really depends on the context. On a pure computational code, it can work really well.
I recently optimized some code asking Claude to "make it faster" 2 different programs. For each, it wrote a benchmark, gathered initial data. Emitted some hypothesis and measured data around them with profilers, then did some changes (behind feature flags), checked the output was identical in either side and through profiling that the right code path was taken, and then benchmarked both.
And it did that for multiple successive changes in both codebases. Some changes were purely algorithmic (better complexity), some were related to tradeoffs between memory and computation (caching intermediate results better), some were about creating less intermediate objects to relieve the memory pressure, some where about a better memory layout to improve data locality.
The annoying part is that some of the code that was optimized was generated by Claude in the first place, so it's a bit frustrating that it didn't do those in the first place. But I guess, my iterative approach to making those tools didn't work on big enough data sets at first where it would have been an issue.