[Haskell-cafe] An interesting paper from Google

2010-10-15 Thread Andrew Coppin
http://k1024.org/~iusty/papers/icfp10-haskell-reagent.pdf I'm sure some of you have seen this already. For those who lack the time or inclination to read through the (six) pages of this report, here's the summary... We [i.e., the report authors] took a production Python system and rewrote b

Re: [Haskell-cafe] An interesting paper from Google

2010-10-15 Thread Iustin Pop
On Fri, Oct 15, 2010 at 09:28:09PM +0100, Andrew Coppin wrote: > http://k1024.org/~iusty/papers/icfp10-haskell-reagent.pdf > > I'm sure some of you have seen this already. For those who lack the > time or inclination to read through the (six) pages of this report, > here's the summary... Nice su

Re: [Haskell-cafe] An interesting paper from Google

2010-10-15 Thread Andrew Coppin
On 15/10/2010 10:43 PM, Iustin Pop wrote: On Fri, Oct 15, 2010 at 09:28:09PM +0100, Andrew Coppin wrote: http://k1024.org/~iusty/papers/icfp10-haskell-reagent.pdf I'm sure some of you have seen this already. For those who lack the time or inclination to read through the (six) pages of this r

Re: [Haskell-cafe] An interesting paper from Google

2010-10-15 Thread Iustin Pop
On Fri, Oct 15, 2010 at 11:08:14PM +0100, Andrew Coppin wrote: > On 15/10/2010 10:43 PM, Iustin Pop wrote: > >On Fri, Oct 15, 2010 at 09:28:09PM +0100, Andrew Coppin wrote: > >>I'm surprised about the profiler. They seem really, really impressed > >>with it. Which is interesting to me, since I can

Re: [Haskell-cafe] An interesting paper from Google

2010-10-15 Thread Andrew Coppin
On 15/10/2010 11:18 PM, Iustin Pop wrote: I know about zipWith. And if the profile tells me I spend too much time in zipWith, it means a few things: - zipWith might have to force evaluation of the results, hence the incorrect attribution of costs - if even after that zipWith is the culprit,

Re: [Haskell-cafe] An interesting paper from Google

2010-10-15 Thread Brandon S Allbery KF8NH
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 10/15/10 16:28 , Andrew Coppin wrote: > I'm surprised about the profiler. They seem really, really impressed with > it. Which is interesting to me, since I can never seen to get anything > sensible out of it. It always seems to claim that my program

Re: [Haskell-cafe] An interesting paper from Google

2010-10-16 Thread Ben Millwood
On Fri, Oct 15, 2010 at 9:28 PM, Andrew Coppin wrote: > I'm still quite > surprised that there's no tool anywhere which will trivially print out the > reduction sequence for executing an expression. You'd think this would be > laughably easy, and yet nobody has done it yet. > I tried to do someth

Re: [Haskell-cafe] An interesting paper from Google

2010-10-16 Thread Dan Doel
On Saturday 16 October 2010 7:04:23 pm Ben Millwood wrote: > On Fri, Oct 15, 2010 at 9:28 PM, Andrew Coppin > > wrote: > > I'm still quite > > surprised that there's no tool anywhere which will trivially print out > > the reduction sequence for executing an expression. You'd think this > > would

Re: [Haskell-cafe] An interesting paper from Google

2010-10-16 Thread wren ng thornton
On 10/16/10 8:25 PM, Dan Doel wrote: On Saturday 16 October 2010 7:04:23 pm Ben Millwood wrote: On Fri, Oct 15, 2010 at 9:28 PM, Andrew Coppin wrote: I'm still quite surprised that there's no tool anywhere which will trivially print out the reduction sequence for executing an expression. You'd

Re: [Haskell-cafe] An interesting paper from Google

2010-10-16 Thread Bernie Pope
On 17 October 2010 11:25, Dan Doel wrote: > On Saturday 16 October 2010 7:04:23 pm Ben Millwood wrote: >> On Fri, Oct 15, 2010 at 9:28 PM, Andrew Coppin >> >> wrote: >> > I'm still quite >> > surprised that there's no tool anywhere which will trivially print out >> > the reduction sequence for ex

Re: [Haskell-cafe] An interesting paper from Google

2010-10-18 Thread Evan Laforge
>> Of course, I'm talking about profiling in time. GHC also enables you >> to profile in space as well. I'm not actually sure to which one >> you're referring. > > In general, time profiling. Although the space profiling is useful too, > it gives you hints on what the (lazy) program does, as oppose

Re: [Haskell-cafe] An interesting paper from Google

2010-10-19 Thread Brandon S Allbery KF8NH
-BEGIN PGP SIGNED MESSAGE- Hash: SHA1 On 10/18/10 21:37 , Evan Laforge wrote: > For instance, currently I have the top consumer of both time and alloc > as 'get', which is 'lift . Monad.State.Strict.get'. Of course it > occurs in a million places in the complete profile, along with > myst

profiling and strictness (was: Re: [Haskell-cafe] An interesting paper from Google)

2010-10-22 Thread Evan Laforge
> Any time you see something "inexplicable" like lots of time being attributed > to something simple like "get", it means that something isn't strict enough > and "get" is having to force a bunch of lazy evaluations to do its job. > Since you're using State.Strict but lift-ing to get there, I'd fir

Re: profiling and strictness (was: Re: [Haskell-cafe] An interesting paper from Google)

2010-11-02 Thread Evan Laforge
> If this is accurate, why would anyone want to use the lazy State? To answer my own question, if you want a monad stack to produce lazy output. E.g. if you want to lazily produce data but also have exceptions and state: ErrorT e (LazyWriterT w (LazyStateT s Identity)) AFAIK this is the only wa