Speeding up Rails 4.2

This is really great – but I guess I'm a little concerned that large performance regressions aren't being caught at an earlier stage. I wonder if there's scope to automatically keep tabs on Rails Edge performance?

This is exceedingly great work. This is the stuff I love coming to HN for. I had no idea Discourse had a dual-boot mode, much less that it had become a de-facto macro benchmark for both Ruby and Rails. That is awesome.

You guys might like our latest gem, it outputs ruby-prof as FlameGraphs https://github.com/oozou/ruby-prof-flamegraph

Sam is a smart guy and an awesome developer. He contributed tons of code for .NET community when he worked at Stack Overflow.

I have done a fair amount of performance optimization work in .NET/C#, so I was curious as to what kind of optimizations are involved in Ruby.

One of the optimization was this:

https://github.com/SamSaffron/rails/commit/9aa2b2d7bf52c0f39...

Three lessons:

1. Always use profiler to identify code bottlenecks. I don't think I would have ever guessed that the string literal is costing memory allocations causing performance issues.

2. I find it sad that this kind of optimization is required in 2015. In any statically typed language, this would be completely unnecessary.

3. Performance optimization makes code less readable. I think it would make sense to add comment explaining why constant ID was declared.

Here's another:

https://github.com/SamSaffron/rails/commit/a668b09ee387bf241...

Same story.

Ruby 2.2 will add almost-automatic-freezing of string hash keys[1]. I wonder how big of an impact this will have on Rails performance.

[1] http://www.sitepoint.com/unraveling-string-key-performance-r...

Great write-up, and thanks Sam and Sean!

Makes me wonder how bad it would have been without Adequate Record? I would imagine it's a bit disheartening for Aaron that all his hard work making AR 2-times faster have been obliterated by other stuff! ..

Sam Saffron has great write-ups. His article on Ruby 2.1 and garbage collection fine-tuning [1] is a must-read

[1] http://samsaffron.com/archive/2014/04/08/ruby-2-1-garbage-co...

Thanks, this is both enormously helpful work for those in the Rails community who depend on the new hotness, and a great writeup for increasing engineering skill levels throughout the community.

Amazing work! I've bookmarked this post. I think that this approach of profiling Discourse on Rails could be use for any other app/service that is to be migrated to Rails 4.2.

You are the man! Thanks for the great insight on the performance.