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Bug #10015

closed

Performance regression in Dir#[]

Added by tenderlovemaking (Aaron Patterson) over 10 years ago. Updated over 8 years ago.

Status:
Closed
Assignee:
-
Target version:
-
ruby -v:
ruby 2.3.0 [x86_64-darwin13.0]
[ruby-core:63591]

Description

r44802 seems to have introduced a performance regression in Dir#[].

Here is the test program:

require 'benchmark'

puts Benchmark.realtime {
  glob = "minitest/*_plugin.rb{,.rb,.bundle}"
  $LOAD_PATH.map { |load_path|
    Dir["#{File.expand_path glob, load_path}"]
  }.flatten.select { |file| File.file? file.untaint }
}

Here is the test time for me:

$ ruby -v test.rb
ruby 2.2.0dev (2014-02-04 trunk 44801) [x86_64-darwin13.0]
0.000341
$ ruby -v test.rb
ruby 2.2.0dev (2014-02-04 trunk 44802) [x86_64-darwin13.0]
0.009333

r44801 seems much faster than r44802.


Related issues 2 (0 open2 closed)

Related to Ruby master - Feature #5994: Dir.glob without wildcards returns pattern, not filenameClosednobu (Nobuyoshi Nakada)02/10/2012Actions
Related to Ruby master - Bug #13167: Dir.glob is 25x slower since Ruby 2.2Closedh.shirosaki (Hiroshi Shirosaki)Actions

Updated by nobu (Nobuyoshi Nakada) over 10 years ago

  • Description updated (diff)

Yes.
Or use case-sensitive platforms.

Updated by tenderlovemaking (Aaron Patterson) over 10 years ago

@nobu (Nobuyoshi Nakada) this change causes a significant increase in Rails boot time on my system.

My application pays a 120ms price for this change. @hsbt (Hiroshi SHIBATA) will pay 520ms:

http://twitter.com/hsbt/status/486378979138367488

Is there a way we can keep the performance on case-insensitive file systems? If there really is no work-around, then we need to make some changes in RubyGems, bundler, minitest, and Rails before trunk is released because many people will complain about slow boot times. :(

Updated by nobu (Nobuyoshi Nakada) over 10 years ago

It might affect unintentionally.
I'll check the bottleneck.

Updated by tenderlovemaking (Aaron Patterson) over 10 years ago

Thanks nobu, I really appreciate it! If it can't be fixed, I have ideas for avoiding the calls to Dir#[], but it will take time to get merged and released.

Updated by normalperson (Eric Wong) over 10 years ago

Btw, you're already paying significant costs for a case-insensitive FS
(not just Ruby, but things like git, too).

Updated by nobu (Nobuyoshi Nakada) almost 10 years ago

  • Status changed from Open to Closed
  • % Done changed from 0 to 100

Applied in changeset r48973.


ChangeLog: fix ref of r48972. [Bug #10015]

Updated by nagachika (Tomoyuki Chikanaga) almost 10 years ago

note: r48975 was reverted at r48976.

Updated by matthewd (Matthew Draper) almost 10 years ago

I don't know what I'm talking about, but this seems like it could use fcntl(2) + F_GETPATH, or getattrlist(2) + ATTR_CMN_NAME.. or something along those lines -- we shouldn't need the loop+fnmatch at all, should we?

Updated by nobu (Nobuyoshi Nakada) almost 10 years ago

Thanks, that's it.

Actions #10

Updated by Intrepidd (Adrien Siami) over 9 years ago

I've noticed a significant slowdown of a rails app when using ruby 2.2.1 rather than 2.1.5.

A slow page was running in 16 seconds with 2.2.1 where it was running in less than 3 seconds with 2.1.5

I tested this very simple benchmark :

require 'benchmark'

puts Benchmark.realtime {
  800000.times do
    Dir['/tmp']
  end
}

it runs in 3.1289695860032225 secs with 2.2.1 and 2.403 secs with 2.1.5

Is this issue still present ?

Actions #11

Updated by nobu (Nobuyoshi Nakada) over 9 years ago

  • Status changed from Closed to Feedback

Adrien Siami wrote:

A slow page was running in 16 seconds with 2.2.1 where it was running in less than 3 seconds with 2.1.5
it runs in 3.1289695860032225 secs with 2.2.1 and 2.403 secs with 2.1.5

What's your platform and filesystem?
As the former seems pretty bigger than the later, they may be caused by different reasons.

Actions #12

Updated by Intrepidd (Adrien Siami) over 9 years ago

Mac OS X Yosemite with the standard filesystem, I believe HFS+ Insensitive

Updated by mkarklins (Magnuss Karklins) over 9 years ago

Experiencing similar results with Adrien's benchmark:
With ruby-2.2.2: 2.9347980790189467
WIth ruby-2.1.5: 1.848318

OS X Yosemite 10.10.3, Journaled HFS+ file system, case insensitive.

Updated by daniel-rikowski (Daniel Rikowski) over 9 years ago

I ran Adrien's benchmark on Windows:

Besides showing a similar performance regression it looks like Dir[] is dramatically slower on Windows:

ruby-2.2.2p95: 161.4
ruby-2.1.6p336: 31.8

(Windows 8.1, SSD, NTFS)

I guess that is because of the GetFileAttributes vs. stat performance difference.

Using Process Monitor I also noticed that in 2.2.2 the (expensive) GetFileAttributesEx function is performed exactly twice as often as in 2.1.6, so part of the problems seems to be repeated (unnecessary?) calls to GetFileAttributes / stat.
(Judging from runtime behaviour only)

Actions #15

Updated by nobu (Nobuyoshi Nakada) over 9 years ago

  • Status changed from Feedback to Closed

Applied in changeset r51106.


dir.c: update path type

  • dir.c (replace_real_basename): update path type by the target
    attributes if possible, to improve the performance. [Bug #10015]

Updated by l.ferreira (Layon Ferreira) over 8 years ago

  • ruby -v changed from ruby 2.2.0dev (2014-02-04 trunk 44802) [x86_64-darwin13.0] to ruby 2.3.0 [x86_64-darwin13.0]
  • Backport changed from 2.0.0: UNKNOWN, 2.1: UNKNOWN to 2.0.0: UNKNOWN, 2.3: UNKNOWN

The problem seems to persist Mac OS X, although is better on 2.3.0, is still a lot slower than 2.1.x.
I have run the benchmark

require "benchmark"
time = []
5.times do
  result = Benchmark.realtime { 800000.times do Dir['/tmp'] end }
  puts result
  time << result
end
average = time.inject{ |sum, el| sum + el }.to_f / time.size

puts "average of: #{average}"

On this machine:

ProductName:	Mac OS X
ProductVersion:	10.11.4
BuildVersion:	15E65

File System Personality:  Case-sensitive Journaled HFS+
Type (Bundle):            hfs
Name (User Visible):      Mac OS Extended (Case-sensitive, Journaled)
Journal:                  Journal size 40960 KB at offset 0xe8e000
Owners:                   Enabled

On the all releases after 2.1.7 and got this results:

=====================================================
2.1.7: benchmarking
=====================================================
Using /Users/admin/.rvm/gems/ruby-2.1.7
2.86774
3.012784
2.867388
2.873973
3.127474
average of: 2.9498717999999995
=====================================================
2.1.8: benchmarking
=====================================================
Using /Users/admin/.rvm/gems/ruby-2.1.8
3.095918
2.981513
2.998208
3.142286
3.048603
average of: 3.0533056000000003
=====================================================
2.1.9: benchmarking
=====================================================
Using /Users/admin/.rvm/gems/ruby-2.1.9
3.022291
2.983054
2.931454
2.944659
3.051114
average of: 2.9865144
=====================================================
2.2.0: benchmarking
=====================================================
Using /Users/admin/.rvm/gems/ruby-2.2.0
4.985971766000148
5.047520838999844
5.066739754000082
5.005606599001112
5.0079711159996805
average of: 5.022762014800174
=====================================================
2.2.1: benchmarking
=====================================================
Using /Users/admin/.rvm/gems/ruby-2.2.1
5.0500176069999725
5.031266175999917
5.011832148000394
5.043594308999673
5.0333263849988725
average of: 5.034007324999766
=====================================================
2.2.2: benchmarking
=====================================================
Using /Users/admin/.rvm/gems/ruby-2.2.2
4.983856856000784
4.975439867999739
5.112457198998527
4.985339404000115
4.961809472000823
average of: 5.003780559799997
=====================================================
2.2.3: benchmarking
=====================================================
Using /Users/admin/.rvm/gems/ruby-2.2.3
4.832416973000363
4.970395954000196
5.007825999999113
4.891315167000357
4.913950877999014
average of: 4.923180994399809
=====================================================
2.2.4: benchmarking
=====================================================
Using /Users/admin/.rvm/gems/ruby-2.2.4
5.083285558999705
5.07147571600035
5.153286901999309
5.110161799999332
5.192000732999077
average of: 5.122042141999555
=====================================================
2.3.0: benchmarking
=====================================================
Using /Users/admin/.rvm/gems/ruby-2.3.0
3.785227087999374
3.9434133479990123
4.052104171998508
3.844644614999197
3.88892919600039
average of: 3.9028636837992963
Actions #17

Updated by nobu (Nobuyoshi Nakada) over 8 years ago

  • Related to Feature #5994: Dir.glob without wildcards returns pattern, not filename added
Actions #18

Updated by nobu (Nobuyoshi Nakada) almost 8 years ago

  • Related to Bug #13167: Dir.glob is 25x slower since Ruby 2.2 added
Actions

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