Imagination PowerVR SDK Blog

Problem with PVRScope using JNI.

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pvrscope

#1

I am using JNI(Java Native Interface) to access PVRScope, in order to access the counter values. The whole 3D program is written in Jave using OpenGL ES 2.0. I open a new thread in Java to regularily sample the PVRScope. I have tried to sample it for different time cycles like 1ms, 2ms, 4ms, 10ms, 16ms, 20ms.

However, all values of counter I got seems random.

Here is a group(active group 0) of data i got:

Group -1: Frame time: 1.1171633

Group -1: Frames per second (FPS): 0.8951243

Group -1: GPU task load: 2D: 57434.145

Group -1: GPU task load: Compute: 57434.145

Group -1: GPU task load: Renderer: 57462.2

Group -1: GPU task load: Tiler: 57459.887

Group -1: GPU task time per frame: 2D: 641.6332

Group -1: GPU task time per frame: Compute: 641.6332

Group -1: GPU task time per frame: Renderer: 641.9466

Group -1: GPU task time per frame: Tiler: 641.9208

Group -1: GPU task time: 2D: 2566.5327

Group -1: GPU task time: Compute: 2566.5327

Group -1: GPU task time: Renderer: 2567.7864

Group -1: GPU task time: Tiler: 2567.683

Group -1: SPM: 0.0

Group 0: ISP load: 0.27483493

Group 0: Shader clock cycles per pixel: 1.0891527

Group 0: Shader clock cycles per vertex: 42.2029

Group 0: Shader load: Pixel: 0.49096373

Group 0: Shader load: Vertex: 0.0014539474

Group 0: Tiler load: 0.35116774

Group 0: Vertices per frame: 69.0

Group 0: Vertices per second: 61.76358



It seems all the data make no sense. If I run the same program again, the data would be different. And some data such as Shader clock cycles per pixel & Shader clock cycles per vertex is stable and make sense.

What is wrong with PVRScope? Why can PVRScopeExample get the correct data but I cannot.

My device is Samsung Galaxy S4 with PowerVR SGX 544MP


#2

Hi,



PVRScope returns the average counter values since the previous sampling period. I would recommend reading our Getting started with PVRScopeStats blog post to familiarise yourself with the behaviour of PVRScope’s counter retrieval process.



We are planning to release the source code of our PVRMonitor utility soon. I’ll update this discussion when that source code is live.



Thanks,

Joe


#3

Hello Bubonger,



We have now released the source code for our PVRMonitor utility:

https://github.com/powervr-graphics/PVRMonitor



The source code demonstrates accessing performance counters using jni.



Please let me know if you have any further questions.



Thanks,

Paul