Changes between Version 12 and Version 13 of LateDmd


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Timestamp:
Aug 30, 2013 2:46:20 PM (18 months ago)
Author:
nfrisby
Comment:

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  • LateDmd

    v12 v13  
    1717  * Ask the performance czars and community for help in determining if we should make -O2 imply -flate-dmd-anal. 
    1818 
    19   * That might involve investigating the more-reliable-looking slowdowns in the New performance numbers section. No slow down was apparent on both platforms (so far), but a couple looked reliable on a given platform. eg typecheck showed the same slowdown regardless of -flate-dmd-anal on the nofib tests (ie same in 10 and 11) and also regardless of mode=norm or mode=slow. Thus it smells like some change in a library function that the main loop of typecheck uses consistently is getting a slowdown. But it's very hard to tell from the numbers and it takes a lot of time to investigate that sort of thing. 
     19  * That might involve investigating the more-reliable-looking slowdowns in the New performance numbers section. No slow down was apparent on both platforms (so far), but a couple looked reliable on a given platform. eg typecheck on the big server showed the same slowdown regardless of -flate-dmd-anal on the nofib tests (ie same in 10 and 11) and also regardless of mode=norm or mode=slow. Thus it smells like some change in a library function that the main loop of typecheck uses consistently is getting a slowdown. But it's very hard to tell from the numbers and it takes a lot of time to investigate that sort of thing. 
    2020    * To proceed: perhaps measure mode=slow on the !MacBook Pro. Also build the libraries with ticky on the big server to search for the hypothetical library function that is slowing down typecheck. 
    2121 
     
    7474=== Main Benefit of Removal === 
    7575 
    76 The clever .hi scheme caused CoreLint errors when combined with -flate-dmd-anal. I irresponsibly cannot remember the recipe for this bug. It was triggered in one of three ways: building GHC, running nofib, or running ./validate. 
     76The clever .hi scheme caused !CoreLint errors when combined with -flate-dmd-anal. I irresponsibly cannot remember the recipe for this bug. It was triggered in one of three ways: building GHC, running nofib, or running ./validate. 
    7777 
    7878Similar to -flate-dmd-anal, abandoning the clever .hi scheme lets us safely import code compiled with/without -ffun-to-thunk from a module compiled without/with -ffun-to-thunk. I can explain this one.