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Too bad you allready started, I was gonna advice you to use reiser4 for optimal disk performace... Also, the "-m" flags of gcc is pretty neat aswell when were talking ...
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  1. #21
    Linux Engineer
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    Too bad you allready started, I was gonna advice you to use reiser4 for optimal disk performace...

    Also, the "-m" flags of gcc is pretty neat aswell when were talking about CFLAGS, for example if you have a 64bit athlon, you could add things like "-m64 -m3dnow -mmmx -mno-push-orgs -maccumulate-outgoing-args" and similar... You find a full list off machine-dependant flags here: http://gcc.gnu.org/onlinedocs/gcc-3....002d64-Options
    And machine-independant optimisation flags here: http://gcc.gnu.org/onlinedocs/gcc-3....timize-Options

  2. #22
    Linux Newbie zdawg's Avatar
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    Just to clear up some confusion about the -O(optimize) flag: anything above 3 is ignored. What '3' specifies (in a nutshell), to the compiler is to compile with all optimizations your cpu is capable of.
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  3. #23
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    Quote Originally Posted by zdawg
    Just to clear up some confusion about the -O(optimize) flag: anything above 3 is ignored. What '3' specifies (in a nutshell), to the compiler is to compile with all optimizations your cpu is capable of.
    Thats what I first thought yeh... Anyway, taken from the GCC manual, the -O3 is just a shortcut for these options:

    -fdefer-pop -fmerge-constants -fthread-jumps -floop-optimize -fcrossjumping -fif-conversion -fif-conversion2 -fdelayed-branch -fguess-branch-probability -fcprop-registers -fforce-mem -foptimize-sibling-calls -fstrength-reduce -fcse-follow-jumps -fcse-skip-blocks -frerun-cse-after-loop -frerun-loop-opt -fgcse -fgcse-lm -fgcse-sm -fdelete-null-pointer-checks -fexpensive-optimizations -fregmove -fschedule-insns -fschedule-insns2 -fsched-interblock -fsched-spec -fcaller-saves -fpeephole2 -freorder-blocks -freorder-functions -fstrict-aliasing -falign-functions -falign-jumps -falign-loops -falign-labels -finline-functions -frename-registers

    Also, there's another -O-flag called -Os which optimize for sieze, and is good for small disks.

    -O3 is definitly not for small disks as it generates gigantic code...

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