Incremental GC in Ruby MRI (opens in new tab)

(bugs.ruby-lang.org)

55 pointsmikkelewis11y ago9 comments

9 comments

If you're running Ruby 1.9.3, go upgrade to 2.1.2. It is such an improvement all around - deploy time, restart time, test time, console startup (if you're using Rails), etc. Just a whole different experience.

And if you've done a 1.8.7 to 1.9.3 upgrade, going from 1.9 to 2.1 is nothing. Piece of cake by comparison.

jerhinesmith11y ago

If you're on heroku (or similarly memory-constrained VPS), it's worth noting that 2.1+ can use significantly more memory.

I've been collecting bookmarks on how to properly tune the GC environment variables in these situations -- hopefully they'll help someone else:

Heroku discussion: https://discussion.heroku.com/t/tuning-rgengc-2-1-on-heroku/...

Using Out-of-band GC on 2.1: http://tmm1.net/ruby21-oobgc/

timr11y ago

Maybe this will help someone, as well...we've been trying to collect all of the different tuning and implementation information on the Ruby GC in one place:

https://www.omniref.com/ruby/2.1.2/symbols/GC#annotation=88&...

1 more reply

joevandyk11y ago

I wish there was a "webapp" environment flag you could set that would tell Ruby to apply reasonable GC/memory settings for a larger / constantly running app.

tehprofessor11y ago

Ruby 2.1's GC is worlds faster, for most applications-- especially with a minor amount of tuning. I saw GC time drop from 20ms to under 5ms (using new relic). Memory usage until GC has gone up a bit though.

I can only hope, and have good reason to after 2.1, that future improvements are so good.

... Ruby just gets better by the year, I love it!

eeeemmm11y ago

Why not to let the user decide when he wants to achieve full GC (As Passenger is doing it between requests) and so avoid the performance regression this patch brings?

ksec11y ago

Since 2.1 has made dramatic decrease in GC time, now the largest contribution on the NewRelic graphs is in Ruby Interpreter itself.

Are there any improvement on that front in Ruby 2.2?

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