1. Xcode
Instruments
Usage
101
Eugene Solodovnykov
http://idevblog.info
@sharpland

2. Instruments app
purpose
Track down difficult-to-reproduce problems in your code
Do performance analysis on your program
Automate testing of your code
Stress-test parts of your application
Perform general system-level troubleshooting
Gain a deeper understanding of how your code works

3. Base templates

5. Leaks
Uses console leaks application (man leaks
will explain you everything)
A lot of applications contain leaks. Our target
is to avoid leaks in our applications :)
Quick example – Droplr application

7. Allocations
Count each allocation in your application’s
session
May help with memory leaks even if Leaks
instrument doesn’t see them
Quick example – Hex Fiend application

8. Hex Fiend dissection
Choose Hex Fiend application as a target
Run Leaks and Allocations instruments
Create a new window and close it (5-7 times)
Leaks just keep silence while Allocations
instrument displays constant chart growth

10. Problem analyzing
Yeah, it’s difficult
Use heapshots

11. - init {
[super init];
lineCountingRepresenter = [[HFLineCountingRepresenter alloc] init];
hexRepresenter = [[HFHexTextRepresenter alloc] init];
asciiRepresenter = [[HFStringEncodingTextRepresenter alloc] init];
scrollRepresenter = [[HFVerticalScrollerRepresenter alloc] init];
layoutRepresenter = [[HFLayoutRepresenter alloc] init]; //is missed in representers
statusBarRepresenter = [[HFStatusBarRepresenter alloc] init];
dataInspectorRepresenter = [[DataInspectorRepresenter alloc] init];
[[hexRepresenter view] setAutoresizingMask:NSViewHeightSizable];
[[asciiRepresenter view] setAutoresizingMask:NSViewWidthSizable | NSViewHeightSizable];
...
return self;
}
- (NSArray *)representers {
return [NSArray arrayWithObjects:lineCountingRepresenter, hexRepresenter, asciiRepresenter,
scrollRepresenter, dataInspectorRepresenter, statusBarRepresenter, nil];
}
- (void)dealloc {
[[NSNotificationCenter defaultCenter] removeObserver:self];
[[self representers] makeObjectsPerformSelector:@selector(release)];
...
[super dealloc];
}
And leaks won’t detect it

12. Time Profiler
Periodically stops the app and records the
stack trace.
Allows to determine where execution time
was spent

14. Can we do more?
Different pre-defined instruments
DTrace-based custom instruments
Mix them!

15. To be continued...