Re: GHC 6.10.2 consuming lots of memory while compiling - help?

On 24/07/2009 23:01, Justin Bailey wrote:

On Fri, Jul 24, 2009 at 2:51 PM, Don Stewart wrote:

...

jgbailey:

...

On Fri, Jul 24, 2009 at 2:02 PM, Don Stewart wrote:

...

Oh, and I note you're not using -O or -O2 either?

-- Don

This is a compile time problem, wouldn't -O make it worse?

Almost certainly!

Ironically adding -O does reduce the compile time in this case. I shouldn't have been so quick to reply!

-O may reduce compilation time by simplifying the code. It's rare in practice, but more likely to happen when you're dealing with a lot of automatically-generated code. To answer the original question, there are various debugging options that will give you an idea of what GHC is up to: -ddump-rn-trace, -ddump-tc-trace -ddump-splices. And +RTS -hT -RTS will give you a heap profile of GHC, which might provide more clues (though matching the profile with what GHC was doing at the time is mostly guesswork). If you think there's something we ought to investigate here, please make a self-contained test case and attach it to a ticket. Cheers, Simon