Re: Performance regressions in HEAD

Hi Simon, > | > Is this the same as you and Simon have been subsequently discussing > | (stack, heap checks), or is it another performance bug? > | > | This is an entirely separate performance bug. The heap check makes one > | of the two variants run 10% slower. This bug effects both variants, > |

RE: Performance regressions in HEAD

Neil | > Is this the same as you and Simon have been subsequently discussing | (stack, heap checks), or is it another performance bug? | | This is an entirely separate performance bug. The heap check makes one | of the two variants run 10% slower. This bug effects both variants, | and gives a 150%

Re: Performance regressions in HEAD

Hi Simon, I bet this is related to getchar. When compiling via C, the C compiler can inline getchar, but with -fasm we have to just call getchar(). Take a look at the asm generated for each way, and try swapping over the fragments that do getchar(). It does appear so. I've hacked the C versi

Re: Performance regressions in HEAD

Neil Mitchell wrote: Hi Simon, I've attached a new sample file, which is what this particular message relates to, although it should be nearly identical to the last one I sent you. There was a small difference between -fasm and -fvia-C, with -fvia-C winning by a few percent. I tracked this do

Re: Performance regressions in HEAD

Hi Simon, I've attached a new sample file, which is what this particular message relates to, although it should be nearly identical to the last one I sent you. There was a small difference between -fasm and -fvia-C, with -fvia-C winning by a few percent. I tracked this down to the getchar() ca

Re: Performance regressions in HEAD

Neil Mitchell wrote: Hi Simon, > The attached charcount.zip shows the optimised cmm and the assembler. > As far as I can tell, the optimised cmm for the hotspot function in > both cases is identical, and the code should be spending all its time > in the hotspot. The names are Main_zdspreludezu9

Re: Performance regressions in HEAD

Hi Simon, > The attached charcount.zip shows the optimised cmm and the assembler. > As far as I can tell, the optimised cmm for the hotspot function in > both cases is identical, and the code should be spending all its time > in the hotspot. The names are Main_zdspreludezu942zull85_entry for 6.7

Re: Performance regressions in HEAD

Neil Mitchell wrote: Hi Simon, - 6.6.1 and 6.7 generate exactly the same Cmm Yes, as far as I can tell. - but their performance differs significantly, - with -fasm or -fvia-C? Both in the default configuration for -O2, then I redid the tests using -fasm on both. If -fasm, did y

Re: Performance regressions in HEAD

% slowdown. Thanks Neil Simon | -Original Message- | From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Neil Mitchell | Sent: 05 July 2007 21:21 | To: cvs-ghc@haskell.org | Subject: Performance regressions in HEAD | | Hi | | Running my benchmark of character counting, with the

RE: Performance regressions in HEAD

| Subject: Performance regressions in HEAD | | Hi | | Running my benchmark of character counting, with the files | ExampleSingle.hs (hand written) and 4.hs (generated by Supero), I get | vastly superior performance using GHC 6.6.1 compared to | ghc-6.7.20070626. | | GHC 6.6.1 | GHC: Elapsed time = 8.047

Re: Performance regressions in HEAD

Hi Simon, - 6.6.1 and 6.7 generate exactly the same Cmm Yes, as far as I can tell. - but their performance differs significantly, - with -fasm or -fvia-C? Both in the default configuration for -O2, then I redid the tests using -fasm on both. If -fasm, did you look at -ddump-opt

Re: Performance regressions in HEAD

Just to be clear here: you're saying that - 6.6.1 and 6.7 generate exactly the same Cmm - but their performance differs significantly, - with -fasm or -fvia-C? If -fasm, did you look at -ddump-opt-cmm? (we have a cmm-to-cmm optimiser pass that runs before the NCG, that flag shows its out

Re: Performance regressions in HEAD

Hi Yet more information. Both were compiled using -O2, and for the ASM/CMM dumps with -fasm as well. Thanks Neil On 7/6/07, Neil Mitchell <[EMAIL PROTECTED]> wrote: Hi Further information: Focusing on 4.hs (I will have another email in detail about the differences between the two), GHC 6.7

Performance regressions in HEAD

Hi Running my benchmark of character counting, with the files ExampleSingle.hs (hand written) and 4.hs (generated by Supero), I get vastly superior performance using GHC 6.6.1 compared to ghc-6.7.20070626. GHC 6.6.1 GHC: Elapsed time = 8.047 seconds Supero: Elapsed time = 2.641 seconds GHC 6.7.