EPC and FPC vs Frame Timing

Hi AYan, you can find the psw for the rar file in your private msg.

We would like to use Nsight not only to debug shader or see improvement on a single feature (SSAO for instance), but mostly to see the real time of our frame (contention and parallelism included). Frame Timing is giving inconsistent timing with lots of huge blank white space.
We recently tested version 5.2 but we still feel that Frame Timing is wrong and inconsistent. Beloow, you’ll find a serialized capture that demonstrate the issue that we have since very early version of Nsight 4.

Here is the link for serialized frame:

Here is the link for frametimings and frameprofiler data:

Related topics are:



OS: Windows 7 x64 sp1
CPU: Intel i7-3930K
RAM: 32Gb DDR3
GPU: Issue has occurred on numerous driver versions but the actual version in this serialized frame is 364.72 on a GTX Titan Black. Issue has appeared on a Maxwell GPU (750 Ti) and on a Kepler 780 GTX

Our application is using Unreal Engine 4.11. The issue was also present 2 years ago using Unity Engine version 4.

As I said in the topic, we tested several time to grab frame at the same spot. Even if there were little obvious changes, the issue was there.

Here are a couple of other things to note:
1- The scrubber in GPU scale give a weird over 80,000,000 microseconds. I understand well that in EPC we can get bigger timing then the real speed of our GPU because of the contention and parallelism that aren’t taken into account, but in this case it is too far away. Sometime it make sense and sometime for some reason the numbers are extremely off.
2- The timing in the Frame Profiler is stating 152ms or sometime similar. I guess the big blank are parts of the issue but we tried to do some maths and remove blank and it was still off. Our game was running way faster then that.
3- It could be a great idea to have the ability to select FPC or EPC right into the scrubber. Of course the default could be EPC.

I would like to mention also that the timing seems extremely off also in the Performance analysis tool (in the timeline). Timing are super big and we don’t know how to understand it.

Thank you very much for your effort to create the best profiling tool for PC! Hopefully in the next release the pure frame profiling will be more obvious and efficient in terms of frame time vs Nsight and App.