On 03/25/2011 08:41 AM, Michael Snoyman wrote:
Hi Sven,
Can I ask you to try things out one more time, this time with
persistent-postgresql 0.4.0.1? I think I fixed some more of the
issue[1].
Thanks,
Michael
[1] http://docs.yesodweb.com/blog/improving-persistent-performance
On Wed, Mar 23, 2011 at 9:23 AM, Sven Koschnicke (GFXpro)
<s.koschnicke@gfxpro.com> wrote:
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.
Sven
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@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@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@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
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