Infering the GPU Active cycles in Mali T-628

Hi Peter Harris

Mali  driver  Version --  r4p0-02rel0

Streamline gatord version 6.10 (DS-5 v5.61)

My problem is as follows :

I use a timer to measure the execution time of OpenCL kernel.  For the OpenCL kernel I am executing at 600MHz , it gives me OpenCL Runtime: 8.222271 seconds.

I profile the same kernel using Streamline (1s sampling interval).  I get the  following statisitcs :

Time Index    GPU Vertex-Tiling-Compute:Activity    Mali Job Manager Cycles:GPU cycles    Mali Job Manager Cycles:JS1 cycles    Mali Core Cycles:Tripipe cycles    Mali Core Cycles:Compute cycles
4    0.00%    2432752    0    4004    0

--- Kernel Start-----
5    3.58%    23830709    21539073    14360724    14357377
6    99.55%    597264018    597099182    385657069    385661788
7    99.52%    597069905    596896010    385843125    385848021
8    99.64%    476883765    476739306    307584997    307589073
9    99.36%    327274357    327183748    211693189    211696096
10    99.52%    597066566    596880847    385265405    385270772
11    99.58%    597396030    597227832    386222691    386227613
12    99.52%    597074759    596898333    386156229    386161004
13    99.50%    596939208    596755666    383900260    383905987
14    12.45%    76855608    74689989    48011367    48008148

---Kernel End---
15    0.00%    2432775    0    4004    0

If GPU activity is 99.36%, GPU active cycles should be 596160000 but streamline reports 327274357.

I calculate my execution time as sum of all GPU cycles from Kernel start till Kernel end .  It gives me 4487654925 cycles =

7.479424875 seconds but the actual runtime is 8.222271 seconds.

I am talking about this discrepancy.. Please help me understand how can I fix this.

Thanks

Hi Peter Harris

Mali  driver  Version --  r4p0-02rel0

Streamline gatord version 6.10 (DS-5 v5.61)

My problem is as follows :

I use a timer to measure the execution time of OpenCL kernel.  For the OpenCL kernel I am executing at 600MHz , it gives me OpenCL Runtime: 8.222271 seconds.

I profile the same kernel using Streamline (1s sampling interval).  I get the  following statisitcs :

Time Index    GPU Vertex-Tiling-Compute:Activity    Mali Job Manager Cycles:GPU cycles    Mali Job Manager Cycles:JS1 cycles    Mali Core Cycles:Tripipe cycles    Mali Core Cycles:Compute cycles
4    0.00%    2432752    0    4004    0

--- Kernel Start-----
5    3.58%    23830709    21539073    14360724    14357377
6    99.55%    597264018    597099182    385657069    385661788
7    99.52%    597069905    596896010    385843125    385848021
8    99.64%    476883765    476739306    307584997    307589073
9    99.36%    327274357    327183748    211693189    211696096
10    99.52%    597066566    596880847    385265405    385270772
11    99.58%    597396030    597227832    386222691    386227613
12    99.52%    597074759    596898333    386156229    386161004
13    99.50%    596939208    596755666    383900260    383905987
14    12.45%    76855608    74689989    48011367    48008148

---Kernel End---
15    0.00%    2432775    0    4004    0

If GPU activity is 99.36%, GPU active cycles should be 596160000 but streamline reports 327274357.

I calculate my execution time as sum of all GPU cycles from Kernel start till Kernel end .  It gives me 4487654925 cycles =

7.479424875 seconds but the actual runtime is 8.222271 seconds.

I am talking about this discrepancy.. Please help me understand how can I fix this.

Thanks

Hi Peter Harris,

Thank you for your inputs. But my question is 

In the following data,

Time Index    GPU Vertex-Tiling-Compute:Activity    Mali Job Manager Cycles:GPU cycles    Mali Job Manager Cycles:JS1 cycles    Mali Core Cycles:Tripipe cycles    Mali Core Cycles:Compute cycles

6    99.55%    597264018    597099182    385657069    385661788
7    99.52%    597069905    596896010    385843125    385848021
8    99.64%    476883765    476739306    307584997    307589073
9    99.36%    327274357    327183748    211693189    211696096
10    99.52%    597066566    596880847    385265405    385270772

Even though GPU Vertex-Tiling-Compute:Activity   is 99.64% why streamline reports 476M gpu cycles instead of 599M ? I checked the temperature of GPU , it is only ~55 C for the above case.

99.64% activity means idle periods are not there. Also temperature of GPU  is only ~55 C. So overheating also is not happening. Then why discrepancy arises. I am unable to understand.