On Thu, 28 Jun 2012, Chetan Jhurani wrote: > Hi devs, > > Is there a way to avoid running the archiver (ar) > every time a petsc directory is compiled? > > The reason I'm asking this is that when libpetsc.lib > becomes large enough (say 100MB+, esp. for debug build), > "ar Sqc" on cygwin takes very long in each directory. > Depending on OS caching, very long can be 10 seconds per > PETSc directory just to run ar. > > It creates a new temp file from scratch, puts stuff from > libpetsc.lib and new stuff in it and then renames the > temp file. As you can imagine, the compilation process is > fast in the beginning but crawls by the end. I've seen > the same IO sequence on Linux (with Sqc flags to ar), but > since cygwin IO is slower the effect is more clearly visible. > Building within a ramdisk leads to 25% faster compilation > but it was more of a curiosity.
'ar Scq' is a hack to speed up builds on Mac [as the previous default 'ar cr' was too slow on it] I don't know if 'ar cr' is also slow on windows. But perhaps it preferable to use '--with-ar='win32fe lib' - perhaps this is faster. ['ar' is unuseable with 64bit windows compilers anyway] Satish
