[Rubygems-developers] RubyGems performance
gsinclair at soyabean.com.au
Fri Dec 10 23:50:26 EST 2004
On Saturday, December 11, 2004, 1:34:03 PM, Gavin wrote:
> As I mentioned in the other thread ("Gem::Specification#copy_of and
> Rails makes tests startup slow"), I'm doing some performance
> investigations of RubyGems. Just FYI I'm posting results here as I
require 'rubygems' : 0.321s
require_gem 'log4r' : 3.601s
require_gem 'RedCloth' : 0.119s
require_gem 'rake' : 0.013s
require_gem 'extensions' : 0.009s
require_gem 'cstemplate' : 0.009s
require_gem 'dev-utils' : 0.014s
The first require_gem is slow; subsequent ones are fast. That's good.
Using require instead of require_gem (with none of these libraries
require 'rubygems' : 0.305s
require 'log4r' : 3.772s
require 'redcloth' : 0.577s
require 'rake' : 0.908s
require 'extensions/all' : 5.594s
require 'celsoft.com/template': 0.362s
require 'dev-utils/debug': 5.697s
Log4r is probably taking a hit as an index is being built up.
RedCloth is comparable to require_gem. Rake and cstemplate both take
a significant hit, explained by the lack of autorequire in their
gemspecs. 'extensions/all' and 'dev-utils/debug' -- my libraries --
are embarassingly slow. Again, it's just that require_gem is fast
because they don't use autorequire.
Just to check, I rearranged the order to see if the first use of
require (after rubygems) takes a hit:
require 'rubygems' : 0.347s
require 'redcloth' : 0.633s
require 'log4r' : 3.961s
require 'rake' : 0.924s
It's inconclusive. RedCloth is consistently taking longer than before
(0.6 instead of 0.2), but Log4r is much the same. One more time, with
Rake leading the way:
require 'rubygems' : 0.304s
require 'rake' : 1.135s
require 'redcloth' : 0.597s
require 'log4r' : 4.547s
Yes, there's definitely an effect. RedCloth is back to normal, and
Rake is taking a bit longer.
Anyway, the REAL test is to pit directly-installed libraries against
gem-installed libraries. So I'll install those six libraries manually
and time their loading. The results are interesting:
require 'rake' : 0.203s
require 'redcloth' : 0.477s
require 'log4r' : 0.430s
require 'extensions/all' : 0.536s
require 'dev-utils/debug': 0.640s
require 'celsoft.com/template': 0.075s
I'll summarise the results in a table.
* "DIRECT" means calling require 'X' where 'X' is installed
directly (via RPA, as it happens).
* "GEM" means calling require 'X' where X is installed as a gem.
* "COMBO" means calling require 'X' _after_ having loaded 'rubygems'
but where the library is also installed directly.
LIBRARY | DIRECT | GEM | COMBO
'rake' | 0.203s | 3.772s | 0.481s
'redcloth' | 0.477s | 0.577s | 1.355s
'log4r' | 0.430s | 0.908s | 2.545s
'extensions/all' | 0.536s | 5.594s | 2.741s
'dev-utils/debug' | 0.640s | 5.697s | 2.056s
'celsoft.com/template' | 0.075s | 0.362s | 0.096s
*** CONCLUSION ***
There's a startling difference between loading certain libraries
directly vs loading them as a gem. And the difference is inconsistent
In all cases, it's slower to load gems than load direct libraries.
That's not surprising. It's worth trying to speed the gem loading up,
because it becomes noticable in the startup time of many applications,
especially small applications that get run a lot (e.g. unit tests,
My next study will look into those libraries to find the reason for
the discrepancies and the inconsistencies.
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