Good screencast. I'd like to see more information on how you can optimize things once you narrow down the culprits. Maybe a checklist of 'gotchas' or something like that. Especially any that are common and not well known.

Great screencast! Thank you very much for all this great information.

Thanks
Eddie Moses

Cool screencasts.. Thanks for sharing.

Little typo detected

should be:
sudo gem install ruby-prof

Great podcast, thanks for the info

@Sam:
its ruby-perf only. (perf => performance)

Nice screencast. I really need to measure performance issues of my app and tutorials like this are of great help. :)

@Carl, I did some previous episodes on optimization, but they don't cover everything so you can expect some more in the future. You can find them out here.
http://railscasts.com/tags/1

@Sam, thanks. Fixed.

Hey Ryan, Passenger (mod_rails) is looking for someone to redo there screencast before they release. I think you would be the perfect person for it.

check it out here...
http://izumi.plan99.net/blog/

@Taylor, thanks for the link. I'll look into doing it. :)

I'm able to run a script, but the files don't contain useful numbers. On Ubuntu (32bit), the first column of profile-flat contains a mix of inf and nan. I'll dig into this, but if you have some guidance, it would be greatly appreciated.

I've tried it on 32-bit Vista, 64-bit Ubuntu & 32-bit Ubuntu. They all report some sort of error. On 64-bit Ubuntu, it aborts with an Integer range error. On Vista, it complains that the files (txt & html) don't exist (though I can open them and see listings for all the methods with no timings). On 32bit Ubuntu, it complains twice about "Could not get a file descriptor referring to the console." These last two create files though the content lacks timings.

How do you get ruby-prof installed under osx? I've tried under both Tiger and Leopard and I get
No definition for prof_get_cpu_frequency

No definition for prof_set_cpu_frequency

on both

I get the same message No definition for prof_get_cpu_frequency both under OS X (Leopard) & Linux (CentOS 5).

When I run the request script I get following:
Warming up once
0.03 sec, 1 requests, 29 req/sec

Profiling 100x
`gem install ruby-prof` to use the profiler

same here... maybe a gems 1.2 issue

Only thing i found is this:

Please use Jeremy Kamper's ruby-prof :http://github.com/jeremy/ruby-prof/tree/master

gem sources -a http://gems.github.com
sudo gem install jeremy-ruby-prof

but does not work for me either...

I had the same problem as everyone above and also failed to get it working with jeremy's gem. I did however get it to work after some investigation.

I took a look at the rails source and it requires ruby-prof 0.6.1. After installing Jeremy's gem I realized it had a slightly different name (jeremy-ruby-prof vs. ruby-prof.) That's probably a github thing but it wasn't satisfying the gem command inside of rails.

So I built the gem from ruby forge source (rake gem, and install manually from the pkg location) and it worked!

Thanks Sean!! that fixed it for me too.

For integration testing you can define session[:user] by adding a second hash, for the session.

get "users/1/edit", {}, {:user_id => 1}

... but this doesn't seem to work for profiling, for some reason.

gotcha : if you are using this with Rails 2.3.2, the request has been discreetly removed so it won't work, as per http://github.com/rails/rails/commit/41af606db385abe429888c5aca8b2e86c8830c24

To add it again manually, follow the instructions at: http://github.com/rails/request_profiler/tree/master

Good luck and thanks again to Ryan for these great contributions!

I need graph gem.what should i use for graph.Please tell me which gem is available for graph.
Thanks,
Manish Kumar

Hello there, I'm having problems viewing your blog on my iPhone, the comment form isn't showing properly for me. (Just thought you might want to know, I'm typing this from my laptop.)

-Jessica

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Thank you share

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Thanks very much for the episodes and best wishse.

hello thank you good information

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Thanks for such a great post and the review, I am totally impressed! Keep stuff like this coming

Thanks for sharing your article. I really enjoyed it. I put a link to my site to here so other people can read it. My readers have about the same interets

tks

Passenger (mod_rails) is looking for someone to redo there screencast before they release.

I feel like I’m often looking for interesting things to read about a variety of subjects, but I manage to include your blog among my reads every day because you have interesting entries that I look forward to. Here’s hoping there’s a lot more great material coming!