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aleksazr
Journeyman III

CPU instructions not accurately profiled

Hello everyone,

I've been using codeXL for a while, and it works pretty good, except for source code viewing,

when most of the time I see that just one single instruction takes most of the execution time.

See the attached pic, where one instruction (out of 20), INC EBP, gets 84%, which is highly unlikely.

Is that a bug in codeXL and can I do something about it?

inc ebp.png

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2 Replies
aleksazr
Journeyman III

Ah, I think I understand now how one single instruction could be taking so much time.

Since I'm writing to random addresses, the cache is not utilized efficiently.

I'm a beginner in profiling, this is my best guess so far.

If that is the case, the problematic instruction should probably be at

0x1141F69 mov [edx+4],ebp, and not inc ebp at 0x1141F6C.

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Hi Aleksazr,

From the snap-shot, i assume you are running "CPU: Time Based Sampling" profile. This profile type should be used for identifying hotspots.

For analyzing instruction level attribution, you need to run "CPU: Instruction-based sampling" profile.

Thanks,

Kalyan P

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