Association for Computing Machinery (ACM)
3 HN recommenders · recommended in 7 months, 2022–2026
1:04:48 · 7.1K views · Oct 28, 2020
Emery Berger argues that performance is hard to measure and deliver on modern systems, showing how code layout and link order can swamp optimization effects. He presents tools that evaluate performance more reliably.
HN points to it whenever benchmarking pitfalls and layout effects come up, as an eye-opening talk on how unreliable naive measurements are.
7 comments from Hacker News
If you're measuring performance and haven't seen this talk by Emery Berger, I highly recommend it. It's mind blowing, but also terrifying when you realize how many mistakes you've been making up until this point. this video
> The main trap is trying to benchmark and profile it without the context of the whole application. Emery Berger's "Performance (Really) Matters" talk also goes into this[0]. He paints a really, really depressing picture of how unreliable benchmarks truly are. Like, things like link order having ridiculous impacts and stuff like that. [0] this video
If you enjoy the science of injecting slowness to determine which component has the largest impact on performance, you would enjoy this work by Emery Berger. Coz: Finding Code that Counts with Causal Profiling [LINK] "Performance (Really) Matters" with Emery Berger this video
I think you're better off watching any of the various recordings "Performance Matters" conference talks[0] by Emery Berger to learn about all the ways that developers are benchmarking the wrong thing using the wrong techniques, and what you could do instead [0] this video
I know, and that is exactly my point. It isn't like "send to REPL" in pretty much any half-decent LISP. And it hurts development comfort, speed and maintenance is way more burdensome than what it could be. Here, you would need to involve a compiler of course and do more due diligence and then run ftrace or something to exchange the code. Also, you would probably in some cases need to make sure, the ordering of code is right as to not hurt performance. (See Emery Berger's talk this video which probably applies here as well.) Of course, with great power comes great responsibility. You could add some optional checking facility, that would be able to roll back the changes to code if some conditions were met.