I'm working on a file compression framework that's GC-only and 32-bit. It reads a file using NSFileHandle 256KB at a time into an NSData object, processes each object into another NSData object, and writes the result to the new file via another NSFileHandle.
If I create a Foundation tool Xcode project, turn on GC and add my FW, then put something like this in main, it works fine, even if the file is > 5 GB.
int main (int argc, const char * argv[]) {
objc_startCollectorThread();
NSAutoreleasePool * pool = [[NSAutoreleasePool alloc] init];
NSString *path = @"path/to/file.ext";
[MyClass processMethod:path];
[pool drain];
return 0;
}
GC kicks in periodically and keeps memory usage to a reasonable level.
However, in when I use the FW in a GC-enabled Cocoa app, it sometimes
fails if I call the process: method either on the main thread or
another one. According to Activity Monitor, both real memory and VM
grow to many GB. Sometimes GC kicks in and real memory shrinks to a
few MB then starts to grow again. However, sometimes it just grows,
and I get the "malloc mmap failed (error code=12)" message.
If I add something like this to the method's processing loop
if (++block % 1000 == 0)
objc_collect(OBJC_EXHAUSTIVE_COLLECTION);
memory usage stays reasonable in the Cocoa app.
I've tried other options in various combinations (e.g.
objc_collect(OBJC_COLLECT_IF_NEEDED) and
objc_clear_stack(OBJC_CLEAR_RESIDENT_STACK)), but only the above seems
to help.
Any idea why GC seems to work automatically in a Foundation tool, but in a Cocoa app it sometimes needs manual invocation?
---- Karl Moskowski <kolpa...@voodooergonomics.com> Voodoo Ergonomics Inc. <http://voodooergonomics.com/>
smime.p7s
Description: S/MIME cryptographic signature
_______________________________________________ Cocoa-dev mailing list (Cocoa-dev@lists.apple.com) Please do not post admin requests or moderator comments to the list. Contact the moderators at cocoa-dev-admins(at)lists.apple.com Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/cocoa-dev/archive%40mail-archive.com This email sent to arch...@mail-archive.com
