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Re: [patch, libfortran] Mark some codepaths as likely/unlikely
- From: "Janne Blomqvist" <blomqvist dot janne at gmail dot com>
- To: "Thomas Koenig" <tkoenig at netcologne dot de>
- Cc: fortran at gcc dot gnu dot org, gcc-patches at gcc dot gnu dot org
- Date: Wed, 15 Oct 2008 14:33:30 +0300
- Subject: Re: [patch, libfortran] Mark some codepaths as likely/unlikely
- References: <1224068121.2932.3.camel@meiner.onlinehome.de>
On Wed, Oct 15, 2008 at 1:55 PM, Thomas Koenig <tkoenig@netcologne.de> wrote:
> here's a straightforward patch to mark some codepaths as
> likely/unlikely, depending on two criteria:
>
> - A codepath that reaches generate_error() is assumed to be unlikely
>
> - A test for GFC_CONVERT_NATIVE is assumed to be likely
Uh? Do you have benchmark results showing an improvement? My gut
instinct would be that the IO library is limited by 1) the hard drive
2) syscall overhead 3) just plain lot of code to trawl through for
every read/write statement resulting in overhead when reading/writing
scalars; branch misprediction penalties would be pretty low on my list
in this case. But hey, I'm willing to have my gut instinct proved
wrong by data. ;)
--
Janne Blomqvist