[Intel-gfx] intel_gpu_top decode..

[Peter Clifton]

Hi,

Can anyone point me at what this intel_gpu_top output (below) indicates
regarding what is limiting the frame-rate of my drawing?

Primarily I'm throwing a lot of triangles and texture coordinates into a
vertex array, compiling the lot into a display list and benchmarking the
frame-rate I can achieve at given window sizes (not vblank limited). For
the data below, I'm just drawing lines (with two triangles each, then
two more at each end for caps). I have some colour changes, but these
are handled with a flush of my vertex array and a glColor call. Colour
changes should be relatively infrequent though.

Round line caps are being drawn using two triangles (to make a square),
with texture coordinates spaced between -1 and 1 to span the square. The
round object is drawn with an implicit texture using this shader:

void main()
{
  float sqdist;

  sqdist = dot (gl_TexCoord[0].st, gl_TexCoord[0].st);
  if (sqdist > 1.0)
    discard;

  gl_FragColor = gl_Color;
}

The line geometry is also hitting this same shader, but with texture
coordinates set to 0.0, 0.0 so it is not clipped.

This is on a GM45. Am I correct in thinking the geometry transfer is the
indicated bottle-neck? (VF CS is vertex fetch command stream, right?)

From the fact the pixel shader is at 70%, I presume I'm not (yet)
fill-rate limited, but not that far from it either.

I've no idea what the other acronyms are, and the PRM doesn't help
immediately. Is UC0 related to clipping? Can I reduce it?


core clock: 400 Mhz
                     ring idle:   1%: ▌                                        
                    ring space: 256/126976 (0%)
                          task  percent busy

                         VF CS:  91%: ████████████████████████████████████▌    
                        UC0 CS:  88%: ███████████████████████████████████▍     
                        ISC CS:  88%: ███████████████████████████████████▍     
                         GS CS:  88%: ███████████████████████████████████▍     
                        VS0 CS:  82%: █████████████████████████████████        
                         CL CS:  82%: █████████████████████████████████        
                    MASM CS CR:  80%: ████████████████████████████████▏        
                   Row 1, EU 3:  78%: ███████████████████████████████▍         
                   Row 0, EU 3:  71%: ████████████████████████████▌            
                  Pixel shader:  70%: ████████████████████████████▏            
                   Bypass FIFO:  69%: ███████████████████████████▊             
                    Windowizer:  68%: ███████████████████████████▍             
                   Row 1, EU 2:  63%: █████████████████████████▍               
                     Filtering:  62%: █████████████████████████                
                   Row 0, EU 2:  60%: ████████████████████████▏                
                        URB CS:  57%: ███████████████████████                  
                  Setup Engine:  55%: ██████████████████████▏                  
                    Map filter:  54%: █████████████████████▊                   
                   Row 1, EU 1:  50%: ████████████████████▏                    
                   Row 0, EU 1:  47%: ███████████████████                      
            Texture decompress:  45%: ██████████████████▏                      
                 Sampler cache:  44%: █████████████████▊                       
                 Texture fetch:  44%: █████████████████▊                       
                   Row 1, EU 0:  43%: █████████████████▍                       
            Projection and LOD:  24%: █████████▊                               
   Dependent address generator:  22%: █████████                                
                    Dispatcher:  18%: ███████▍                                 
         Message Arbiter row 1:  11%: ████▌                                    
                    SVDR CS CR:   6%: ██▌                                      
                     EM1 CS CR:   5%: ██▏                                      
                    SVSM CS CR:   2%: █     


Best regards,
           

-- 
Peter Clifton

Electrical Engineering Division,
Engineering Department,
University of Cambridge,
9, JJ Thomson Avenue,
Cambridge
CB3 0FA

Tel: +44 (0)7729 980173 - (No signal in the lab!)
Tel: +44 (0)1223 748328 - (Shared lab phone, ask for me)