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Optimization. Help. HZB

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    Optimization. Help. HZB

    Hello everyone. Need help! (posted it on answerhub, but seems noone know ((( )
    we making a VR project, and i have an issue with hzb cost. It`s ridiculously high. What can produce such issue?

    i know what HZB is a occlusion culling thing - so it`s cost can rise from objects and resolution? am i right? But in scene i have around 400-500 drawcalls with foliage, 1-1,2k poly (but polycount goes to base pass?)

    and when i`m profile with third party tools, like Intel GPA kit. It shows what my hzb is 0.1 ms in total and gpu scene time around - 5ms.

    sorry for my English, i`m not a native speaker =(
    Last edited by Etherlord; 11-27-2017, 06:56 AM.

    #2
    From the image you supplied, it looks like you are spawning a ton of particles. If you look at the Particle Simulation section you will see that it is taking over 16 MS for whatever is in there. I would first check out what particle systems you are using and what they are doing and then go from there.

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      #3
      Originally posted by Sam Deiter View Post
      From the image you supplied, it looks like you are spawning a ton of particles. If you look at the Particle Simulation section you will see that it is taking over 16 MS for whatever is in there. I would first check out what particle systems you are using and what they are doing and then go from there.
      Thank you for your reply!!!

      I don`t see it at "MAX" column (think it`s just random spike or totally not see it) - my bad, gonna check it.
      but in AVG column it`s only 0.71ms, while HZB 7+/22+ in both columns, it`s too strange =(

      about Particles - iirc it`s 2-4 emiters which use a materials for volumetric fog for small waterfalls.

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        #4
        just check it. seems my screencap soft provoked a glitch, but - not much difference in HZB - 3,5-5 ms avg/ 8-10 max, and for Particle Simulation - 0.8-1,5 ms avg / 4 max depends on level.

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          #5
          Originally posted by Etherlord View Post

          Thank you for your reply!!!

          I don`t see it at "MAX" column (think it`s just random spike or totally not see it) - my bad, gonna check it.
          but in AVG column it`s only 0.71ms, while HZB 7+/22+ in both columns, it`s too strange =(

          about Particles - iirc it`s 2-4 emiters which use a materials for volumetric fog for small waterfalls.
          You are right, I was just looking at the Max section instead of the first one. Other things to check out would be to examine what your GPU is doing by pressing CTRL + Shift + Comma(,) and post a image of what your GPU usage looks like.

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            #6
            hm... when i`m press it game start lag like hell, and give me noting in return after 3 mins, but iirc - it`s just shortcut for "profileGPU" command? if yes - i`m add screen from GPUvisaulizer and intel Frame Analyzer.

            ninja edit: But yea - when i`m look at log for UE profiler i see bunch of tickin BPs...taking care of they now.
            Attached Files
            Last edited by Etherlord; 11-29-2017, 11:43 AM.

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              #7
              Right away I am seeing that you do in fact have a particle effect that is taking almost 1 ms to render which is very expensive for this area so I would start to have a look at your particle effects and make sure you are not spawning too many GPU particles or something like that. I would also take a look at what you are doing for Volumetric Fog as that is taking 1.33

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                #8
                Ty for your advice.

                I think i know why PS costs 1+ they not removed by level streaming. Forgot to move them to lvls after they be set up
                Volumetric fog costs 1.3 cause of high shadows settings (seems it`s cost 0.8ms for turned in on high settings and 0.2ms for each light source, which use volumetric) - it`s fine, or mb not, but we need that here. If i set sg.shadowquality to 2 (it seems medium) - fog cost down to 0.2 + 0.05 for each source. But they loose their nice effect

                But how it correlates with high HZB cost? Why it high on UE stat GPU and ProfileGPU, and low in intel soft i can`t understand

                Comment


                  #9
                  Make sure you are profiling in a packaged Development build, since there is a lot of noise in editor, especially unexpected high cost in HZB (which is actually not possible because HZB is a fixed cost algorithm)

                  Comment


                    #10
                    Originally posted by Luoshuang View Post
                    Make sure you are profiling in a packaged Development build, since there is a lot of noise in editor, especially unexpected high cost in HZB (which is actually not possible because HZB is a fixed cost algorithm)
                    yeap - i`m profiling a packaged build. all ingame stat screen from where. (with high HZB in stat gpu)

                    and i`m wondering why switching to Forward makes HZB drop to 0.05ms +- (but cause of light setup - it slowly overall )

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                      #11
                      Hi, it`s me again. I revised the whole project... and nothing terrible consuming found except code (i dunno how much our code is optimized, cause i`m not a programmer ) . Can code (CPU) time incorrectly displayed and somehow go to HZB?

                      yeap - i know issue about HZB and DX11, but i can`t run our project on DX12 (4.17) - always crashing
                      Last edited by Etherlord; 12-14-2017, 07:31 AM.

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