[Haskell-cafe] Significant compilation slowdown when using Data.CaseInsensitive.mk

[Brendan Hay]

Apologies, I should have used SHA references in the links:

> The code which seems to cause this is here:
>
https://github.com/brendanhay/amazonka/blob/release/0.1.4/core/src/Network/AWS/Data/Internal/Text.hs#L51

https://github.com/brendanhay/amazonka/blob/049fab83dd71e3f2e8aa5643902f95e83604db0c/core/src/Network/AWS/Data/Internal/Text.hs#L52

> With the downstream project having about 68 call sites for the above
function starting here:
>
https://github.com/brendanhay/amazonka/blob/release/0.1.4/amazonka-ec2/gen/Network/AWS/EC2/Types.hs#L1465

https://github.com/brendanhay/amazonka/blob/04f620d3e01a05c30db99afa07a84d07eee12434/amazonka-ec2/gen/Network/AWS/EC2/Types.hs#L1465


On 6 January 2015 at 20:07, Brendan Hay <brendan.g.hay at gmail.com> wrote:

> Hi,
>
> I've recently run into an issue whereby changing textual case comparison
> to use the Data.CaseInsensitive.mk
> <http://hackage.haskell.org/package/case-insensitive-1.2.0.3/docs/Data-CaseInsensitive.html> smart
> constructor causes substantial
> differences to outputted core language and a related compilation speed
> regression.
>
> The code which seems to cause this is here:
>
> https://github.com/brendanhay/amazonka/blob/release/0.1.4/core/src/Network/AWS/Data/Internal/Text.hs#L51
>
> With the downstream project having about 68 call sites for the above
> function starting here:
>
> https://github.com/brendanhay/amazonka/blob/release/0.1.4/amazonka-ec2/gen/Network/AWS/EC2/Types.hs#L1465
>
> For comparison, the previous version used Attoparsec.Text.takeText
> <http://hackage.haskell.org/package/attoparsec-0.12.1.2/docs/Data-Attoparsec-Text.html>
> and Text values.
>
> Here are some hand wavy points of interest:
>
> * Before (Case Sensitive)
> Function: takeText = Attoparsec.Text.takeText
> Time (real): 2m27.735s
> amazonka-ec2/gen/Network/AWS/EC2/Types.hs (simpl): {terms: 242,688, types:
> 310,463, coercions: 31,215}
>
> * After (Case Insensitive)
> Function: takeCI = Data.CaseInsensitive.mk <$> Attoparsec.Text.takeText
> Time (real): 11m31.937s
> amazonka-ec2/gen/Network/AWS/EC2/Types.hs (simpl): {terms: 1,384,779,
> types: 465,656, coercions: 33,510}
>
> I'm finding the outputted core rather unwieldy to analyse, but the main
> difference seems to be the inclusion of huge swathes of case statements
> like:
> https://gist.github.com/brendanhay/5a57f073d5a7d196a1ad
>
> It would be appreciated if someone could help me to understand in simple
> terms why
> the use of case-insensitive causes this.
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.haskell.org/pipermail/haskell-cafe/attachments/20150107/b5708ef0/attachment.html>