# Ruby "Speedup" hints? **URL:** \ **Category:** ruby-talk\ **Created:** [17 March 2008 12:42 UTC](https://rubytalk.org/t/ruby-speedup-hints/45236 "2008-03-17T12:42:29Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Marc\_Heiler](https://avatars.discourse-cdn.com/v4/letter/m/e8c25b/32.png) [@Marc\_Heiler](https://rubytalk.org/u/Marc_Heiler)\ **Post date:** [17 March 2008 12:42 UTC](https://rubytalk.org/t/ruby-speedup-hints/45236/1 "2008-03-17T12:42:29Z")
Anyone of you has a few hints on how to speed up ruby code? (Note - not writing it, but running it 馃槈 ) I only have a few hints, like 5... would love to extend it. So without further ado: - Using \<\< instead of += for Strings as += creates a new object whereas \<\< will simply work on the current object. - Use Inline C for critical methods (had to include that ;\> ) - Reusing variable names might be better than using a lot of different variables - for is faster than .each on Arrays - .last is faster than [0] - .zero? is faster than == 0 If you know a few more hints, please add! > **路路路** > > -- > Posted via [http://www.ruby-forum.com/](http://www.ruby-forum.com/). ---
**Author:** ![Robert\_K1](https://yyz1.discourse-cdn.com/flex029/user_avatar/rubytalk.org/robert_k1/32/1830_2.png) [@Robert\_K1](https://rubytalk.org/u/Robert_K1)\ **Post date:** [17 March 2008 13:04 UTC](https://rubytalk.org/t/ruby-speedup-hints/45236/2 "2008-03-17T13:04:52Z")
> Anyone of you has a few hints on how to speed up ruby code? > (Note - not writing it, but running it 馃槈 ) > > I only have a few hints, like 5... would love to extend it. > > So without further ado: > > - Using \<\< instead of += for Strings as += creates a new object > whereas \<\< will simply work on the current object. I'd replace that with the general rule to avoid object creation because that will cover more cases (Array#concat vs. Array#+, String#gsub! vs. String#gsub etc.). > - Use Inline C for critical methods (had to include that ;\> ) You could argue that this does not speed up Ruby code but replaces it with something else. So it's questionable whether this item should be on the list. > - Reusing variable names might be better than using a lot of > different variables Are you talking about a fact or a guess here? You write "might" - which indicates to me that this is not a proven fact. > - for is faster than .each on Arrays > > - .last is faster than [0] I guess you meant Array#last is faster than Array#[-1] or Array#first is faster than Array#[0]. > - .zero? is faster than == 0 Interesting, I did not know that. But the difference is really small: robert@fussel ~ $ time ruby -e '1\_000\_000.times { 0.zero? }' real 0m0.748s user 0m0.468s sys 0m0.108s robert@fussel ~ $ time ruby -e '1\_000\_000.times { 1.zero? }' real 0m0.748s user 0m0.483s sys 0m0.124s robert@fussel ~ $ time ruby -e '1\_000\_000.times { 0 == 0 }' real 0m0.869s user 0m0.561s sys 0m0.108s robert@fussel ~ $ time ruby -e '1\_000\_000.times { 1 == 0 }' real 0m0.857s user 0m0.562s sys 0m0.124s robert@fussel ~ $ > If you know a few more hints, please add! - freeze Strings that you are going to use as Hash keys. Often bad design makes programs slow. While these are valid points often the bigger effect can be achieved by proper designing an application (i.e. use a Hash for frequent lookups instead of traversing an Aarry). Kind regards   robert > **路路路** > > On 17.03.2008 13:42, Marc Heiler wrote: ---
**Author:** ![Ilan\_Berci](https://avatars.discourse-cdn.com/v4/letter/i/94ad74/32.png) [@Ilan\_Berci](https://rubytalk.org/u/Ilan_Berci)\ **Post date:** [17 March 2008 13:22 UTC](https://rubytalk.org/t/ruby-speedup-hints/45236/3 "2008-03-17T13:22:32Z")
Marc Heiler wrote: > Anyone of you has a few hints on how to speed up ruby code? > (Note - not writing it, but running it 馃槈 ) > > I only have a few hints, like 5... would love to extend it. There is only 1 hint: PROFILE IT!!! everything else is BS.. hth ilan > **路路路** > > -- > Posted via [http://www.ruby-forum.com/\](http://www.ruby-forum.com/%5C). ---
**Author:** ![M\_Edward\_Ed\_Borasky1](https://avatars.discourse-cdn.com/v4/letter/m/e9c0ed/32.png) [@M\_Edward\_Ed\_Borasky1](https://rubytalk.org/u/M_Edward_Ed_Borasky1)\ **Post date:** [17 March 2008 14:00 UTC](https://rubytalk.org/t/ruby-speedup-hints/45236/4 "2008-03-17T14:00:36Z")
Marc Heiler wrote: > Anyone of you has a few hints on how to speed up ruby code? > (Note - not writing it, but running it 馃槈 ) > > I only have a few hints, like 5... would love to extend it. > > So without further ado: > > - Using \<\< instead of += for Strings as += creates a new object > whereas \<\< will simply work on the current object. > > - Use Inline C for critical methods (had to include that ;\> ) > > - Reusing variable names might be better than using a lot of > different variables > > - for is faster than .each on Arrays > > - .last is faster than [0] > > - .zero? is faster than == 0 > > If you know a few more hints, please add! > **[Writing Efficient Ruby Code (Digital Short Cut) | InformIT](https://www.informit.com/store/writing-efficient-ruby-code-digital-short-cut-9780321540034)** > > This short cut focuses on a number of coding patterns that are useful when trying to get maximum speed out of performance-critical sections of Ruby code. Anti-patterns, that is, coding idioms, which should be avoided in performance-sensitive code... A whole book full of tips! ---
**Author:** ![Jan\_Svitok](https://avatars.discourse-cdn.com/v4/letter/j/cab0a1/32.png) [@Jan\_Svitok](https://rubytalk.org/u/Jan_Svitok)\ **Post date:** [17 March 2008 16:51 UTC](https://rubytalk.org/t/ruby-speedup-hints/45236/5 "2008-03-17T16:51:27Z")
ParseDate#parsedate is expensive - it uses rationals, gcd and other heavy stuff to convert from [D, M, Y, H, M, S] to timestamp. Once we did a log merger and we ordered the entries by time. We saved a lot of processing time by storing the timestamps in the logs along with the formatted date. (They were removed afterwards during formatting.) ERB#new is expensive. Cache compiled templates if they are to be reused. Use /o switch for Regexp literals that contain constant #{substitutions} (i.e. that do not depend on function parameters) > **路路路** > > On Mon, Mar 17, 2008 at 1:42 PM, Marc Heiler \ wrote: > > > Anyone of you has a few hints on how to speed up ruby code? > > (Note - not writing it, but running it 馃槈 ) > > If you know a few more hints, please add! ---
**Author:** ![Gerardo\_Santana\_Gome](https://avatars.discourse-cdn.com/v4/letter/g/b5ac83/32.png) [@Gerardo\_Santana\_Gome](https://rubytalk.org/u/Gerardo_Santana_Gome)\ **Post date:** [17 March 2008 17:17 UTC](https://rubytalk.org/t/ruby-speedup-hints/45236/6 "2008-03-17T17:17:22Z")
When generating text output, using StringIO is faster than using puts > **路路路** > > On Mon, Mar 17, 2008 at 12:42 PM, Marc Heiler \ wrote: > > > Anyone of you has a few hints on how to speed up ruby code? > > (Note - not writing it, but running it 馃槈 ) > > > > I only have a few hints, like 5... would love to extend it. > > -- > Gerardo Santana ---
**Author:** ![John\_Carter](https://avatars.discourse-cdn.com/v4/letter/j/2bfe46/32.png) [@John\_Carter](https://rubytalk.org/u/John_Carter)\ **Post date:** [17 March 2008 21:52 UTC](https://rubytalk.org/t/ruby-speedup-hints/45236/7 "2008-03-17T21:52:55Z")
Sounds like time to repost (yet again, can't we add this to a FAQ somewhere?) > **[WebMD - Better information. Better health.](https://www.webmd.com/)** > > The leading source for trustworthy and timely health and medical news and information. Providing credible health information, supportive community, and educational services by blending award-winning expertise in content, community services, expert... Please add your hints (preferably with a benchmark to show the magnitude of the improvement) to that page. Thanks! John Carter Phone : (64)(3) 358 6639 Tait Electronics Fax : (64)(3) 359 4632 PO Box 1645 Christchurch Email : john.carter@tait.co.nz New Zealand > **路路路** > > On Mon, 17 Mar 2008, Marc Heiler wrote: > > > Anyone of you has a few hints on how to speed up ruby code? > > (Note - not writing it, but running it 馃槈 ) ---
**Author:** ![Siep\_Korteling](https://avatars.discourse-cdn.com/v4/letter/s/41988e/32.png) [@Siep\_Korteling](https://rubytalk.org/u/Siep_Korteling)\ **Post date:** [18 March 2008 23:44 UTC](https://rubytalk.org/t/ruby-speedup-hints/45236/8 "2008-03-18T23:44:02Z")
Marc Heiler wrote: > (...) > If you know a few more hints, please add! Date and DateTime are time consuming. Time however, is not. require 'benchmark' N = 10000 Benchmark.bmbm do |bm|    bm.report 'empty' do      N.times do 1 end    end    bm.report 'DateTime' do      N.times {DateTime.new}    end    bm.report 'Date' do      N.times {Date.new}    end    bm.report 'Time' do      N.times {Time.new}    end end                user system total real empty 0.000000 0.000000 0.000000 ( 0.000000) DateTime 3.687000 0.063000 3.750000 ( 3.813000) Date 1.281000 0.000000 1.281000 ( 1.313000) Time 0.016000 0.000000 0.016000 ( 0.015000) Regards, Siep > **路路路** > > -- > Posted via [http://www.ruby-forum.com/\](http://www.ruby-forum.com/%5C). ---
**Author:** ![Sean\_Allen](https://avatars.discourse-cdn.com/v4/letter/s/df788c/32.png) [@Sean\_Allen](https://rubytalk.org/u/Sean_Allen)\ **Post date:** [17 March 2008 13:57 UTC](https://rubytalk.org/t/ruby-speedup-hints/45236/9 "2008-03-17T13:57:44Z")
and it certainly will eventually lead to programmer confusion esp when dynamically scoped blocks come into play. > **路路路** > > On Mar 17, 2008, at 9:04 AM, Robert Klemme wrote: > > > > - Reusing variable names might be better than using a lot of > > > different variables > > > > Are you talking about a fact or a guess here? You write "might" - which indicates to me that this is not a proven fact. ---
**Author:** ![Avdi\_Grimm1](https://avatars.discourse-cdn.com/v4/letter/a/e47c2d/32.png) [@Avdi\_Grimm1](https://rubytalk.org/u/Avdi_Grimm1)\ **Post date:** [17 March 2008 14:20 UTC](https://rubytalk.org/t/ruby-speedup-hints/45236/10 "2008-03-17T14:20:59Z")
+1 All discussions of performance tuning are meaningless without profiling numbers. > **路路路** > > On Mon, Mar 17, 2008 at 9:22 AM, Ilan Berci \ wrote: > > > There is only 1 hint: > > > > PROFILE IT!!! > > -- > Avdi ---
**Author:** ![Ken\_Bloom](https://avatars.discourse-cdn.com/v4/letter/k/f08c70/32.png) [@Ken\_Bloom](https://rubytalk.org/u/Ken_Bloom)\ **Post date:** [17 March 2008 17:40 UTC](https://rubytalk.org/t/ruby-speedup-hints/45236/11 "2008-03-17T17:40:06Z")
Is that in any way a speedup hint? or is it just a safety hint? What causes the speedup? --Ken > **路路路** > > On Mon, 17 Mar 2008 14:01:51 +0100, Robert Klemme wrote: > > > - freeze Strings that you are going to use as Hash keys. > > -- > Ken (Chanoch) Bloom. PhD candidate. Linguistic Cognition Laboratory. > Department of Computer Science. Illinois Institute of Technology. > [http://www.iit.edu/~kbloom1/](http://www.iit.edu/~kbloom1/) ---
**Author:** ![Paul\_Brannan](https://avatars.discourse-cdn.com/v4/letter/p/76d3ee/32.png) [@Paul\_Brannan](https://rubytalk.org/u/Paul_Brannan)\ **Post date:** [17 March 2008 18:08 UTC](https://rubytalk.org/t/ruby-speedup-hints/45236/12 "2008-03-17T18:08:52Z")
This doesn't make sense. One can easily call #puts on a StringIO object. Do you have a concrete example/benchmark that demonstrates the difference? Paul > **路路路** > > On Tue, Mar 18, 2008 at 02:17:22AM +0900, Gerardo Santana G?mez Garrido wrote: > > > On Mon, Mar 17, 2008 at 12:42 PM, Marc Heiler \ wrote: > > \> Anyone of you has a few hints on how to speed up ruby code? > > \> (Note - not writing it, but running it 馃槈 ) > > \> > > \> I only have a few hints, like 5... would love to extend it. > > > > When generating text output, using StringIO is faster than using puts ---
**Author:** ![Paul\_Brannan](https://avatars.discourse-cdn.com/v4/letter/p/76d3ee/32.png) [@Paul\_Brannan](https://rubytalk.org/u/Paul_Brannan)\ **Post date:** [17 March 2008 15:06 UTC](https://rubytalk.org/t/ruby-speedup-hints/45236/13 "2008-03-17T15:06:59Z")
Profiling only tells you where performance bottlenecks are. It does nothing for letting you know how to fix those bottlenecks. That's where benchmarks come into play. Paul > **路路路** > > On Mon, Mar 17, 2008 at 11:20:59PM +0900, Avdi Grimm wrote: > > > On Mon, Mar 17, 2008 at 9:22 AM, Ilan Berci \ wrote: > > \> There is only 1 hint: > > \> > > \> PROFILE IT!!! > > > > +1 > > > > All discussions of performance tuning are meaningless without > > profiling numbers. ---
**Author:** ![Jan\_Svitok](https://avatars.discourse-cdn.com/v4/letter/j/cab0a1/32.png) [@Jan\_Svitok](https://rubytalk.org/u/Jan_Svitok)\ **Post date:** [17 March 2008 18:08 UTC](https://rubytalk.org/t/ruby-speedup-hints/45236/14 "2008-03-17T18:08:23Z")
Otherwise Hash will dup and freeze the String anyway. [class Hash - RDoc Documentation](http://ruby-doc.org/core/classes/Hash.html#M002878) (What is not mentioned there is that frozen strings will not be duplicated.) > **路路路** > > On Mon, Mar 17, 2008 at 6:40 PM, Ken Bloom \ wrote: > > > On Mon, 17 Mar 2008 14:01:51 +0100, Robert Klemme wrote: > > \> - freeze Strings that you are going to use as Hash keys. > > > > Is that in any way a speedup hint? or is it just a safety hint? What > > causes the speedup? ---
**Author:** ![Gerardo\_Santana\_Gome](https://avatars.discourse-cdn.com/v4/letter/g/b5ac83/32.png) [@Gerardo\_Santana\_Gome](https://rubytalk.org/u/Gerardo_Santana_Gome)\ **Post date:** [18 March 2008 05:40 UTC](https://rubytalk.org/t/ruby-speedup-hints/45236/15 "2008-03-18T05:40:43Z")
$ time ruby a.rb 10\_000\_000 \> /tmp/a && sleep 3 && time ruby b.rb 10\_000\_000 \> /tmp/b; printf "\a" real 1m45.305s user 1m27.581s sys 0m17.715s real 0m59.049s user 0m41.984s sys 0m16.997s $ cat a.rb times = ARGV[0].to\_i times.times { puts "hola mundo" } $ cat b.rb require 'stringio' times = ARGV[0].to\_i output = StringIO.new times.times { output.write("hola mundo\n") } output.rewind print output.read The difference increases in real world reports. > **路路路** > > On Mon, Mar 17, 2008 at 6:08 PM, Paul Brannan \ wrote: > > > On Tue, Mar 18, 2008 at 02:17:22AM +0900, Gerardo Santana G?mez Garrido wrote: > > \> On Mon, Mar 17, 2008 at 12:42 PM, Marc Heiler \ wrote: > > \> \> Anyone of you has a few hints on how to speed up ruby code? > > \> \> (Note - not writing it, but running it 馃槈 ) > > \> \> > > \> \> I only have a few hints, like 5... would love to extend it. > > \> > > \> When generating text output, using StringIO is faster than using puts > > > > This doesn't make sense. One can easily call #puts on a StringIO > > object. > > > > Do you have a concrete example/benchmark that demonstrates the > > difference? > > > > Paul > > -- > Gerardo Santana ---
**Author:** ![Robert\_K1](https://yyz1.discourse-cdn.com/flex029/user_avatar/rubytalk.org/robert_k1/32/1830_2.png) [@Robert\_K1](https://rubytalk.org/u/Robert_K1)\ **Post date:** [18 March 2008 10:04 UTC](https://rubytalk.org/t/ruby-speedup-hints/45236/16 "2008-03-18T10:04:46Z")
As Jano mentioned it's the skipped #dup for frozen Strings that makes the speedup. irb(main):002:0\> s="foo" =\> "foo" irb(main):003:0\> h={s=\>1} =\> {"foo"=\>1} irb(main):004:0\> [s.object\_id, h.keys.first.object\_id] =\> [1073545320, 1073545340] irb(main):005:0\> s.freeze =\> "foo" irb(main):006:0\> h={s=\>1} =\> {"foo"=\>1} irb(main):007:0\> [s.object\_id, h.keys.first.object\_id] =\> [1073545320, 1073545320] irb(main):008:0\> Kind regards robert > **路路路** > > 2008/3/17, Ken Bloom \: > > > On Mon, 17 Mar 2008 14:01:51 +0100, Robert Klemme wrote: > > \> - freeze Strings that you are going to use as Hash keys. > > > > Is that in any way a speedup hint? or is it just a safety hint? What > > causes the speedup? > > -- > use.inject do |as, often| as.you\_can - without end ---
**Author:** ![ThoML](https://avatars.discourse-cdn.com/v4/letter/t/d78d45/32.png) [@ThoML](https://rubytalk.org/u/ThoML)\ **Post date:** [18 March 2008 09:00 UTC](https://rubytalk.org/t/ruby-speedup-hints/45236/17 "2008-03-18T09:00:02Z")
> The difference increases in real world reports. This and some other tips seem specific to either ruby 1.8 or 1.9. While StringIO seems much faster with 1.9, in my world, the difference is rather marginal with 1.8. Also, the following is slightly faster with 1.8: times = ARGV[0].to\_i times.times { STDOUT.puts "hola mundo" } YMMV etc. ---
**Author:** ![Marc\_Heiler](https://avatars.discourse-cdn.com/v4/letter/m/e8c25b/32.png) [@Marc\_Heiler](https://rubytalk.org/u/Marc_Heiler)\ **Post date:** [18 March 2008 10:43 UTC](https://rubytalk.org/t/ruby-speedup-hints/45236/18 "2008-03-18T10:43:27Z")
Hi there, Thanks for the feedback so far. 馃檪 "PROFILE IT!!! everything else is BS." As for profiling, you can always do profiling of course, but why copy the efforts others did on it already? Example - General Statements done such as the one by Robert Klemme seem to hold true no matter how much profiling one would do anyway:   "I'd replace that with the general rule to avoid object creation because   that will cover more cases (Array#concat vs. Array#+, String#gsub! vs.   String#gsub etc.)." Personally I like such simple truths. 馃檪 > **路路路** > > -- > Posted via [http://www.ruby-forum.com/](http://www.ruby-forum.com/). ---
**Author:** ![James\_Tucker](https://avatars.discourse-cdn.com/v4/letter/j/ccd318/32.png) [@James\_Tucker](https://rubytalk.org/u/James_Tucker)\ **Post date:** [19 March 2008 11:17 UTC](https://rubytalk.org/t/ruby-speedup-hints/45236/19 "2008-03-19T11:17:23Z")
Do you not realize that this is fundamentally telling you your terminal is super-slow? This has nothing to do with ruby itself, really. Try it on some other platforms and tool stacks, for goodness sake. And FYI, this is why context specific profiling is far more important than any of these strange idioms you're talking about. Oh, and this is only really true for short strings and relatively small amounts of memory. Try doing that whilst say, stream editing a 1TB file. This whole direction of thought is broken, honestly. > **路路路** > > On 18 Mar 2008, at 05:40, Gerardo Santana G贸mez Garrido wrote: > > > On Mon, Mar 17, 2008 at 6:08 PM, Paul Brannan \ \> wrote: > > > > > On Tue, Mar 18, 2008 at 02:17:22AM +0900, Gerardo Santana G?mez \>\> Garrido wrote: > > > > > > > On Mon, Mar 17, 2008 at 12:42 PM, Marc Heiler \\>\> \> wrote: > > > > > > > > > Anyone of you has a few hints on how to speed up ruby code? > > > > > (Note - not writing it, but running it 馃槈 ) > > > > > > > > > > I only have a few hints, like 5... would love to extend it. > > > > > > > > When generating text output, using StringIO is faster than using puts > > > > > > This doesn't make sense. One can easily call #puts on a StringIO > > > object. > > > > > > Do you have a concrete example/benchmark that demonstrates the > > > difference? > > > > > > Paul > > > > $ time ruby a.rb 10\_000\_000 \> /tmp/a && sleep 3 && time ruby b.rb > > 10\_000\_000 \> /tmp/b; printf "\a" > > > > real 1m45.305s > > user 1m27.581s > > sys 0m17.715s > > > > real 0m59.049s > > user 0m41.984s > > sys 0m16.997s > > $ cat a.rb > > times = ARGV[0].to\_i > > times.times { puts "hola mundo" } > > $ cat b.rb > > require 'stringio' > > > > times = ARGV[0].to\_i > > output = StringIO.new > > times.times { output.write("hola mundo\n") } > > output.rewind > > print output.read > > > > The difference increases in real world reports. > > -- > > Gerardo Santana ---
**Author:** ![Paul\_Brannan](https://avatars.discourse-cdn.com/v4/letter/p/76d3ee/32.png) [@Paul\_Brannan](https://rubytalk.org/u/Paul_Brannan)\ **Post date:** [19 March 2008 13:25 UTC](https://rubytalk.org/t/ruby-speedup-hints/45236/20 "2008-03-19T13:25:32Z")
I think you are demonstrating the difference between IO#puts and IO#write (which still surprised me). cout@bean:~/tmp$ time ruby a.rb 1\_000\_000 \> /dev/null real 0m2.769s user 0m2.660s sys 0m0.044s cout@bean:~/tmp$ time ruby b.rb 1\_000\_000 \> /dev/null real 0m1.315s user 0m1.244s sys 0m0.020s cout@bean:~/tmp$ time ruby c.rb 1\_000\_000 \> /dev/null real 0m1.256s user 0m1.160s sys 0m0.036s cout@bean:~/tmp$ cat c.rb times = ARGV[0].to\_i times.times { $stdout.write "hola mundo\n" } And on my machine with 10\_000\_000 iterations I starting digging into swap with the stringio solution: cout@bean:~/tmp$ time ruby a.rb 10\_000\_000 \> /dev/null real 0m27.841s user 0m25.694s sys 0m0.112s cout@bean:~/tmp$ time ruby b.rb 10\_000\_000 \> /dev/null real 0m54.888s user 0m11.333s sys 0m0.504s cout@bean:~/tmp$ time ruby c.rb 10\_000\_000 \> /dev/null real 0m13.141s user 0m11.749s sys 0m0.100s Paul > **路路路** > > On Tue, Mar 18, 2008 at 02:40:43PM +0900, Gerardo Santana G?mez Garrido wrote: > > > $ time ruby a.rb 10\_000\_000 \> /tmp/a && sleep 3 && time ruby b.rb > > 10\_000\_000 \> /tmp/b; printf "\a" > > > > real 1m45.305s > > user 1m27.581s > > sys 0m17.715s > > > > real 0m59.049s > > user 0m41.984s > > sys 0m16.997s > > $ cat a.rb > > times = ARGV[0].to\_i > > times.times { puts "hola mundo" } > > $ cat b.rb > > require 'stringio' > > > > times = ARGV[0].to\_i > > output = StringIO.new > > times.times { output.write("hola mundo\n") } > > output.rewind > > print output.read [Next page](https://rubytalk.org/t/ruby-speedup-hints/45236.md?page=2)