http://gcc.gnu.org/bugzilla/show_bug.cgi?id=25708
Joost VandeVondele <Joost.VandeVondele at mat dot ethz.ch> changed:
What |Removed |Added
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Depends on| |40958
--- Comment #21 from Joost VandeVondele <Joost.VandeVondele at mat dot ethz.ch>
2012-08-24 14:00:40 UTC ---
I did another timing experiment on compiling CP2K. I found that on my server,
compiling with -fsyntax-only is as fast as just compiling at -O0. I believe the
reason for this is that module reading is dominating the compile time. In CP2K
each module is included only once per file, so I think it is the efficiency of
reading the module that matters most. My guess would be that the human readable
format of the .mod file is the source of most inefficiency. Is it still
important to the development of gfortran that the .mod file is in this form ?
If I count the number of times a module is used, and multiply that with the
size, I have about 1Gb of .mod files being parsed per CP2K compile (for about
35Mb of Fortran).
