[gregdunn]

Disclaimer: I work at AWS on an unrelated team. I was not involved in development of this product. Opinions stated are my own, and not necessarily a reflection of my employer. Nothing here is being posted in any sort of official capacity.

There's lots of focus here in the comments on the code reviewer portion, but one of the things I'm most excited about is the profiler - https://aws.amazon.com/codeguru/features/

I do a lot of performance engineering work, and one of my go to tools for visualizing where programs are spending their time is flamegraphs. While you can certainly create them with profilers besides CodeGuru (and I do not work with Java, so I haven't yet had the chance to check out CodeGuru for any of my use cases), I'm super excited about anything that gets more people using them. They make it very easy to see where your optimization opportunities are, and I have personally found them very useful when working with our customers - they're way easier, in my opinion, to go through and explain than just looking at raw perf output or similar.

[richdougherty]

A profiling tool I want to try out—it seems almost magical—is Coz. It can estimate the effect of speeding up any line of code. It does this by pausing (!) other threads, so it gives a 'virtual' speed up for that line.

What's interesting is that this technique correctly handles inter-thread effects like blocking, locking, contention, so it can point out inter-thread issues that traditional profilers and flame graphs struggle with.

Summary: https://blog.acolyer.org/2015/10/14/coz-finding-code-that-co...

Video presentation: https://www.youtube.com/watch?v=jE0V-p1odPg&t=0m28s

Coz: https://github.com/plasma-umass/coz

JCoz (Java version): http://decave.github.io/JCoz/ and https://github.com/Decave/JCoz

[antpls]

I have never heard of this kind of profiling before, thanks for sharing

[skynetv2]

Have you tried https://cloud.google.com/profiler/ ?

[antonhag]

Yes, indeed! Especially when paired with an continuously running profiler, one can learn quite a bit about one's code. It's actually rather surprising to me that they have not quite caught on earlier.

A bit of an (almost) shameless plug is a project I have been working on at https://blunders.io. A bit similar to the Code Guru profiler, but with a different feature set.

[tclancy]

Seconded. I used them a lot when I worked for myself on old-school single server apps but have struggled to convince my team now that I work on something spread across AWS instances. I'd just brought the concept up again this week for a hackathon project but this looks like we could buy our way to what I want for cheap (compared to overall hosting). I suspect it may pay for itself.

[kugelblitz]

The Profiler reminds me a bit of PHP Symfony's https://blackfire.io/. Even the graphs (flamegraphs) have some strong similarities (e.g. https://blackfire.io/docs/reference-guide/analyzing-timeline...).

I've used Blackfire for a while, and this type of visualization is definitely helpful for finding bottlenecks in web performance. I've been able to reduce page load by caching big chunks that I was able to see in the graph / timeline.

[pacoverdi]

I, for one, am very interested in flamescope [1]. Not tried it yet but it's like a time machine that allows to zoom on a given time interval and look at a flamegraph of what happened at that moment.

You can look at the introductory video [2] to get an idea

[1] https://github.com/Netflix/flamescope [2] https://www.youtube.com/watch?v=cFuI8SAAvJg

EDIT: missing anchor

[bentcorner]

Does anyone know of a good flame graph visualizer for callstacks? Particularly one that allows you to drill down into a stack. Bonus points if you can diff two data sets. I recently built an in-app profiler and am trying to work out the analysis side of things to make life easier for the other developers on my team.