Now I'm trying to optimize the startup time of the application and currently I want to reduce the time spent by the bootloader of the OS image.
From dyld (1), I found two environment variables: DYLD_PRINT_STATISTICSand DYLD_PRINT_INITIALIZERS.
DYLD_PRINT_STATISTICScauses dyld to print statistics about how dyld spent his time. This is his conclusion when I launched the application after the command purge.
total time: 5.9 seconds (100.0%)
total images loaded: 130 (101 from dyld shared cache, 0 needed no fixups)
total segments mapped: 105, into 12914 pages with 840 pages pre-fetched
total images loading time: 1.8 seconds (31.0%)
total dtrace DOF registration time: 0.09 milliseconds (0.0%)
total rebase fixups: 137,658
total rebase fixups time: 1.1 seconds (19.4%)
total binding fixups: 28,502
total binding symbol lookups: 1,127, average images searched per symbol: 0.1
total binding fixups time: 452.28 milliseconds (7.6%)
total weak binding fixups time: 188.52 milliseconds (3.1%)
total bindings lazily fixed up: 130 of 1,164
total initializer time: 2.3 seconds (38.7%)
total symbol trie searches: 2611
total symbol table binary searches: 118
total images defining/using weak symbols: 13/65
Apparently, when calling the initializer functions, a lot of time is used. So I tried to DYLD_PRINT_INITIALIZERSget a list of initializer functions.
I really got them, but there was no time information on them, for example, time stamp, just a few lines:
dyld: calling initializer function 0x25170 in MY_APPLICATE_PATH
It is useless for me to find the target initializers for optimization.
, :
dyld?- , - ,
dyld? DTrace Instruments? - .
OSX, Windows.