I need to measure an algorithm’s times and I’ve heard about CHUD. I’ve taken a look at it, but i don’t know which tool i must use nor how do they work. Does anyone know it?

Thanks in advance

---

Hm, I don’t know about algorithm’s time, but with General/SharkCHUD you can analyze your program and see the percentage of the processing time used by the different classes/functions during the analyze phase. With that you can see which function call used the most processing power and you also get some hints what to optimize. Very nice tool.

–General/ThomasSempf

---

If you just want to find out how long a function takes to complete, you can use clock() to time it. It’s not terribly accurate, so you should run the function in a loop to make sure it takes at least several seconds to finish, then divide by the number of iterations to get a time per call. CHUD is for overall performance evaluation on a more complex level, like finding out not only how much time something takes but where it’s spending that time and why. It’s overkill for your purpose, I believe. Most importantly, you won’t get a timing, I think?

---

Thanks. After playing a bit with CHUD that is what i think. I was using clock() but my project’s director told me about using CHUD, but I suppose it’s not exactly what he thought.

---

If your algorithms use General/ObjC methods (which they won’t if you use legacy code in C), then you could use General/AspectCocoa to make the timings more dynamic (switch them on and off) and flexible (add/remove methods for the timings). –General/CharlesParnot

I don’t know if you get ns with clock(), but I think darwin can get you this kind of precision if you need it. I have seen it on apple’s website somewhere. –General/CharlesParnot

---

Saturn (CHUD) is good for timing and profiling code. Also, gettimeofday (man 2 gettimeofday) will yield microsecond precision (standard disclaimer regarding system clocks and preemptive multitasking variations apply) if you want to time things yourself in code.

---

Wouldn’t General/NSLog be a good solution? Just make an General/NSLog entry at the beginning of your algorithm and at the end and employ a little subtraction. Or is this not an Obj-C project?

---

You can also use the CPU’s timestamp counters which are incremented every cycle.

#define tbl(x) asm volatile (“mftb %0,268\n\t”:”=r” (x) ) #define tbu(x) asm volatile (“mftb %0,269\n\t”:”=r” (x) )

/** returns an unsigned long long read from the CPU’s timestamp counters. */ inline unsigned long long gettimestamp() { unsigned long long full;

register unsigned int upper; register unsigned int lower;

tbl(lower); tbu(upper);

full = upper; full = full « 32;

return full+upper; }

Its not the most beautiful code, and should be compiled -O3 (gcc is better at optimizing than I am). But it does save having to make a system call, and is much lighter weight.