[web-devel] Performance of Yesod 0.7 fourteen times slower than Rails 2.3?

Sven Koschnicke (GFXpro) s.koschnicke at gfxpro.com
Wed Mar 23 08:23:10 CET 2011

Great that you found a way to speed things up! I'm looking forward to 
the blog post. I will run some more tests with the improved code, just 
let me know when its available. Is someone working on improving the 
postgres database backend? Maybe I could help there, the bad performance 
with postgres is really a showstopper for me.


On 03/23/2011 08:13 AM, Michael Snoyman wrote:
> This was a great example of a performance bug being exactly where you
> don't expect it. I'm planning on writing up a blog post on this
> adventure later, but for the quick summary: the Criterion benchmarks
> have gone from 23.7ms (== 23,700us) to 141us. Meaning this is a 200
> fold speedup for some operations. This came from switching a large
> monad transformer stack to a single RWS monad. But more on that in the
> blog post.
> I've run your test a few more times: it still seems like there's a
> slowdown from the database code, but I think the widget performance
> bug was the big issue. After some more testing on my end, I'll put the
> code on Hackage. Would you give the test another shot after that?
> Thanks again for bringing this up!
> Michael
> On Mon, Mar 21, 2011 at 5:41 PM, Sven Koschnicke (GFXpro)
> <s.koschnicke at gfxpro.com>  wrote:
>> Hello,
>> I think your guess wasn't completely wrong. I tested with Sqlite now, and
>> with that rails and yesod are equally slow (rails 11.81 secs vs yesod 11.36
>> secs). But its also interesting that your code change speeds it up.
>> (I put the sqlite benchmark at
>> https://github.com/SKoschnicke/performance-test/tree/sqlite)
>> My first guess was actually that its the marshalling which slows yesod so
>> much and that rails uses some clever optimizations there, but I haven't got
>> enough insight to validate that.
>> Greetings
>>   Sven
>> On 03/21/2011 01:49 PM, Michael Snoyman wrote:
>>> Looks like my initial guess was completely wrong: on my system, almost
>>> no time is spent on the database query. Instead, it looks like there's
>>> some kind of performance issue with Hamlet. For example, changing line
>>> 20 of Handler/Quote.hs from "addWidget" to "addHtml" increases
>>> performance dramatically (25 sec to 4.5 sec). I'll need to spend some
>>> more time to properly diagnose the problem. Again, thanks for bringing
>>> this to my attention.
>>> Michael
>>> On Mon, Mar 21, 2011 at 12:40 PM, Michael Snoyman<michael at snoyman.com>
>>>   wrote:
>>>> Firstly, thank you for running this benchmark: it's the only way we
>>>> can find out where Yesod needs to be fixed.
>>>> I haven't had a chance to look into the code properly, but it looks
>>>> like this is more a test of the database backend than of the web
>>>> framework. I'll try to get to this myself later, but it would be very
>>>> interesting to see the difference in response times between PostgreSQL
>>>> and sqlite. Currently, persistent-sqlite binds directly to the sqlite
>>>> C API, while persistent-postgresql uses HDBC. It's entirely possible
>>>> that HDBC is adding some overhead.
>>>> One of the items on our wish list[1] is to migrate away from HDBC.
>>>> Having hard numbers like you are providing will help us figure out our
>>>> priorities a bit better.
>>>> Thanks,
>>>> Michael
>>>> [1] http://wiki.yesodweb.com/Wishlist
>>>> On Mon, Mar 21, 2011 at 12:10 PM, Sven Koschnicke (GFXpro)
>>>> <s.koschnicke at gfxpro.com>    wrote:
>>>>> Hello,
>>>>> I'm coming from a Rails background and was very impressed by the
>>>>> features of
>>>>> the Yesod Web Framework. Working on an trading app in Rails I wanted to
>>>>> port
>>>>> some features of this app to a Yesod app just to learn the framework and
>>>>> because we have some performance issues with Rails.
>>>>> The first thing I noticed was that the Yesod app was significantly
>>>>> slower
>>>>> than the Rails app at trivial tasks. I am very astonished about that. I
>>>>> thought Rails should be slower because of its interpreted nature. I made
>>>>> some benchmarking and measured that a simple Rails app is fourteen times
>>>>> faster than a Yesod app that did the same thing (loading some records
>>>>> from
>>>>> the database and displaying them). Did I made a mistake or is my
>>>>> understanding, that the compiled app should be faster, just wrong?
>>>>> I documented the results on github:
>>>>> https://github.com/SKoschnicke/performance-test
>>>>> Greetings
>>>>>   Sven Koschnicke
>>>>> _______________________________________________
>>>>> web-devel mailing list
>>>>> web-devel at haskell.org
>>>>> http://www.haskell.org/mailman/listinfo/web-devel

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