Optimizing iOS method in objective-c
times.count in for(int x = 0; x != times.count; x++) is a method call, move it to a variable. Also, you should probably use the &lt; instead of != as it is more common.

However, as you don't really need the index of the element, you can replace both iterations

for(int i = 0; i != filtered.count; i++) {
    unit = [filtered objectAtIndex:i];

by native iteration

for (LogUnit* unit in filtered) {

Is @autoreleasepool necessary in every iteration? Having it outside for should help performance as well. In most application you are not required to use @autoreleasepool at all.

NSString *attributeName = @"realTime";
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"%K IN %@", attributeName, [times objectAtIndex:x]];
// Filter the objectArray by the time, so we don't have to run through all the objects in objectArray, and check if time is right.
NSArray *filtered  = [objectArray filteredArrayUsingPredicate:predicate];


Your filtering doesn't do what your comment describes. You don't want to run through all the objects but that's exactly the thing filteredArrayUsingPredicate: does. Only using reflexion and moving the objects into a new array. By using the filtering code, you are losing performance.

There are various code quality issues not related to performance:


usage of variable names x, f, h, objectArray. Use more descriptive names or use i, j, k for iterators.
Move some code to separate methods, e.g. view generation.
Don't use NULL in Obj-C, use nil. NULL is to be used only when you interact with C pointers, not Obj-C objects.
[comp isEqualToString:NULL] will never evaluate to YES (true)
if(_breakPlease == false) Don't use false in Obj-C. Use YES or NO. Never ever compare a BOOL with a bool literal. Use logical operators instead, e.g. if (!_breakPlease).


Algorithm performance:

The main problem of your algorithm is its complexity. Basically you have two arrays and you compare objects from an array with all objects from the other array. That's O(n^2)

There are many ways how you could improve this, I will list some of them:


Don't use a NSArray to store the log units. Use a NSDictionary where time is the key and log unit, or possibly array of log units with the same time, is the value. Finding log units with the given time will be trivial then.
Sort times and objectArray by time. You can then iterate through both arrays at the same time and you get O(n + n * log n).