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From: Eric Wong <e@80x24.org>
To: =?utf-8?Q?Br=C3=A1ulio?= Bhavamitra <braulio@eita.org.br>
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Subject: Re: Request Queueing after deploy + USR2 restart
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Bráulio Bhavamitra <braulio@eita.org.br> wrote:
> Sakis, ressurecting this.
> 
> I'm seeing this after the upgrade from rails 3.2 to rails 4.2. Maybe it is
> because of adequate record and other "cached on first time used" stuff.

I'm not knowledgeable enough to comment on Rails , but
"cache on first time used" includes the caches in the YARV RubyVM
itself:

1) inline method cache
2) inline constant cache
3) global method cache

The only way to warm up the inline caches is to actually run your
code paths (perhaps in warmup code).  After warmup, you need to
avoid defining new classes/constants or doing includes/extends/etc
because those things invalidate caches.

ruby-core has been working to reduce the size of internal data
structures in C to improve CPU cache utilization (which might make
the explicit RubyVM-level caches less necessary for small apps).

Ruby 2.3 should include some more speedups in method lookup;
but having the smallest possible code base always helps.

Regardless of language or VM implementation; big code and data
structures invalidates caches on the CPU faster than smaller
code and data structures.

So reduce your application code size, kill unnecessary features,
use a smaller framework (perhaps Sinatra, or even just Rack),
load fewer libraries, etc.


And yes, this mindset to making things smaller extends to mail:
stop bloating them with top-posts and insanely long signatures.