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author | Jon Moss <me@jonathanmoss.me> | 2016-09-01 18:02:55 -0400 |
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committer | Jon Moss <me@jonathanmoss.me> | 2016-10-02 15:12:46 -0400 |
commit | 353122c9da6caa30f1d4a117d4c543cd567ca3bb (patch) | |
tree | d090cdec7d32affe9c2df398825d1f4611771511 /activerecord/README.rdoc | |
parent | da0fdd6bf529df8806ddb4b97e4bb31c95249e0e (diff) | |
download | rails-353122c9da6caa30f1d4a117d4c543cd567ca3bb.tar.gz rails-353122c9da6caa30f1d4a117d4c543cd567ca3bb.tar.bz2 rails-353122c9da6caa30f1d4a117d4c543cd567ca3bb.zip |
Speed up Time.zone.now
@amatsuda, during his RailsConf talk this past year, presented a
benchmark that showed `Time.zone.now` (an Active Support joint)
performing 24.97x slower than Ruby's `Time.now`. Rails master appears to
be a _bit_ faster than that, currently clocking in at 18.25x slower than
`Time.now`. Here's the exact benchmark data for that:
```
Warming up --------------------------------------
Time.now 127.923k i/100ms
Time.zone.now 10.275k i/100ms
Calculating -------------------------------------
Time.now 1.946M (± 5.9%) i/s - 9.722M in 5.010236s
Time.zone.now 106.625k (± 4.3%) i/s - 534.300k in 5.020343s
Comparison:
Time.now: 1946220.1 i/s
Time.zone.now: 106625.5 i/s - 18.25x slower
```
What if I told you we could make `Time.zone.now` _even_ faster? Well,
that's exactly what this patch accomplishes. When creating `ActiveSupport::TimeWithZone`
objects, we try to convert the provided time to be in a UTC format. All
this patch does is, in the method where we convert a provided time to
UTC, check if the provided time is already UTC, and is a `Time` object
and then return early if that is the case, This sidesteps having to continue on,
and create a new `Time` object from scratch. Here's the exact benchmark
data for my patch:
```
Warming up --------------------------------------
Time.now 124.136k i/100ms
Time.zone.now 26.260k i/100ms
Calculating -------------------------------------
Time.now 1.894M (± 6.4%) i/s - 9.434M in 5.000153s
Time.zone.now 301.654k (± 4.3%) i/s - 1.523M in 5.058328s
Comparison:
Time.now: 1893958.0 i/s
Time.zone.now: 301653.7 i/s - 6.28x slower
```
With this patch, we go from `Time.zone.now` being 18.25x slower than
`Time.now` to only being 6.28x slower than `Time.now`. I'd obviously love some
verification on this patch, since these numbers sound pretty interesting... :)
This is the benchmark-ips report I have been using while working on this:
```ruby
require 'benchmark/ips'
Time.zone = 'Eastern Time (US & Canada)'
Benchmark.ips do |x|
x.report('Time.now') {
Time.now
}
x.report('Time.zone.now') {
Time.zone.now
}
x.compare!
end
```
cc @amatsuda
cc performance folks @tenderlove and @schneems
![Pretty... pretty... pretty good.](https://media.giphy.com/media/bWeR8tA1QV4cM/giphy.gif)
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