Slowmotion in RF2 RC multiplayer

Discussion in 'Bug Reports' started by szczebrzeszyn, Oct 9, 2023.

  1. szczebrzeszyn

    szczebrzeszyn Registered

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    Hi,
    I just downloaded release candidate and gave new multiplayer system a try.

    Online match is stuck in slow motion mode - the speed of the car and the physics (cornering) does not match the real time. Everyone is overtaking me like I'm in a STROLLer.

    Bug demonstration in a video (stuttering comes from recording, my FPS was stable 60+): https://youtu.be/kYPTz4f5qrM?si=eBbfU7pZBbW0rvt7
    Only multiplayer mode is affected. I tried same track and car in single player with lots of AI (also release candidate) and the game runs fine
    Logs: https://drive.google.com/file/d/1ahmq_KWHXeU1-ASS2lgSUTtCQgsrLo23/view?usp=drive_link

    gtx1650, win10, i7-7700hq, 32gb ram, the game is installed on slow, external hdd, stable internet connection (not sure why other cars are lagging)
     
    Last edited: Oct 9, 2023
  2. szczebrzeszyn

    szczebrzeszyn Registered

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  3. The video reminds me of three effects: GPU overload, CPU overload, network bandwidth too low. Also I would get rid of the USB drive - if it is rather old and slow it is not acting as an internal HDD because of the USB design and will be missing nearly all the features an internal drive attached to SATA or whatever is offering and using. The USB drive could cause CPU "stuttering" e.g.

    Also check your FX settings - road and environment reflections, shadows and special fx (like sparks) are GPU intensive - there are a lot of guides around how to reduce FX settings without loosing that much eye candy.

    You can check CPU and GPU hitting CTRL and F (I think) - question: is it the same in single player mode or only in multiplayer? If last, I would say your internet connection is stable, but has limited bandwidth and high latency (it is recommended not to use wireless lan) - if it is lagging more and more while driving this could be also caused by collisions on your connection (which is pretty unlikely nowadays but still happening from time to time) which may caused by a broken network card, a bad cable (if used), wrong network settings (if changed from default) e.g.
     
  4. szczebrzeszyn

    szczebrzeszyn Registered

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    Thanks for suggestions. I have recorded performance data when the game started to slow down:
    https://drive.google.com/file/d/1flzYD5cyv3Pq5KWA-Zyr15pBynl8peup/view?usp=drive_link

    I can rule out GPU overload as the game runs smoothly 60+fps. CPU time is also very low (0.01-0.02s).
    Most importantly I reproduced the issue in single player of STABLE (non-beta) steam version by starting practice, playing a bit then moving to qualies (just like in multiplayer). The AI cars start lagging almost like in the video above, but at the same time they go faster than me.

    I cannot test a faster hard drive at this moment, maybe later this week if I get lucky. If it's the hard drive fault then the question is whether my super slow usb drive triggered some rare bug OR the game physics calculations are sensitive to disk speed.
     
    Last edited: Oct 10, 2023
  5. Ok - if it happens in single player mode, too, network can be dropped as a cause.

    The USB drive is not hitting any bug nor game physics are hard drive sensitive, but USB is - afaik at least 2.0 - CPU bounded so it cannot operate self-sufficient (more or less) like an internal drive connected to SATA.

    USB has some more significant limitations which are not relevant to e.g. controllers like wheel or button box but to hard drives, USB sticks and so on (https://www.keil.com/pack/doc/mw/USB/html/_u_s_b__endpoints.html).

    What also comes to mind: if it is a 2.0 drive connected to an 3.0 port this may cause problems and / or the type of cable you are using; compare it to the disorders happen when running an USB 3.0 drive with a bad or faulty or bad isolated cable near your WLAN device / antenna ...

    Also if the drive is pretty old it can be faulty itself. And ... external drives are not the fastest ones if it comes to rotation speed (rpm).

    Of course it all should only affect loading times, but I am not quite sure if sound e.g. is loaded on demand and if the drive causes problems on the USB bus itself it might be that one CPU core is more or less blocking the whole system while being busy e.g. with USB handshaking ...
     
  6. Lazza

    Lazza Registered

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    Use Ctrl-C in game to bring up the CPU graph. If the purple bar is approaching the right hand side that will cause the issues, which sounds likely. (the top green section is for CPU graphics processing, which can affect framerates but shouldn't cause slowdowns)

    Try turning off replay recording, that should be one of the few/only things that uses the disk while driving.

    If you have any third-party plugins installed try without them.

    But as StoneRacing says, external drives might just be difficult to run with. rF2 is very sensitive to CPU use because of its "live" nature.
     
    Deleted member 58016 likes this.
  7. @Lazza you are right - I did not see it clearly ... if using an external drive which might be slow and having replay recording set to high detail level (or full) may cause the slow down and - as described above - increasing from start on (I think a replay file could be around several hundred MB).
     
  8. szczebrzeszyn

    szczebrzeszyn Registered

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    I actually was on USB2.0, now connected to USB 3.0 but there's no difference.
    I also tried reducing number of sound effects from 255 to 32 and turning Master Volume to 0% - no difference.

    What do you mean game is not sensitive? I thought my video proves, that something (spike in cpu time? disk loading?) is influencing the performance of my car. If it's caused by slow disk then I should ask what's the baseline? Does having m.2 disk allow to drive a car faster than regular ssd or there's a cap on phys calculation (e.g 100 per sec) and anything faster than my usb will not make a difference?

    However I don't see a direct correlation between cpu time of a frame and the observed slowdown. The cpu time is usually between 0.01 and 0.02 . Shouldn't that be good enough?

    edit:
    checking replay...
     
  9. szczebrzeszyn

    szczebrzeszyn Registered

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    Turning off replay recording did not help.
    Ctrl+C shows that purple bar is reaching over the limit. I guess that means that sim frame time went over the time?
    I'll try again later this week with external m2 disk connected over usb-c and update the thread.
    thanks
     
  10. Connecting an USB 2.0 drive to an USB 3.0 port does not improve performance as expected (there may be an improvement, but it would be measurable only ... if ...).

    USB is designed as an external port for mobile / pluggable devices - and older USB ports / hubs are CPU dependent. It makes no difference if the drive is fast or not when it demands much of CPU time (don't now exactly nowadays but in the past there were interrupts which did not show up in CPU load, but in load factor itself (not shown in Windows) and CPU).

    I would not install rF2 to another external drive, wether it is M.2 or something other - I am not sure if it is the USB itself but it is the first thing I would change (to internal drive).
     
  11. Lazza

    Lazza Registered

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    The CPU usage causing you to run out of realtime will cause slow motion when offline (plus make a mess of AI), and will make you slower online. Anything 'fast enough' (or not having CPU-eating issues) will run the game at the same speed, with the exact same physics.

    It generally doesn't take all that much CPU to run the game fine, in modern terms. Your CPU should be fine, as long as it's running a fast enough clock - you'll want to disable any power saving or otherwise find a way to disable things like speedstep so that your CPU doesn't try to power down. In the old days even disabling hyperthreading was useful but I don't think that's still the case.

    Remember that because rF2 is sensitive to timing, the 'issue' won't always show in normal CPU occupancy logs. So judge it by the Ctrl-C, and if you are going to monitor/log anything try the CPU clock speed to check that it's running at a good speed and not fluctuating.
     
  12. szczebrzeszyn

    szczebrzeszyn Registered

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    Thanks for the insight.
    I moved to new m2 pci drive. Unfortunately the game is still slowing down (although appears to be sligh. I am now investigating the possibility of thermal throttling of my laptop. However I have not observed any issues in other games like iRacing, ACC or Dirt Rally.
    gpu usage: https://drive.google.com/file/d/1b8TSG5n2wmXFKHae-pEhv_lM6CTntiOZ/view?usp=sharing
    temps: https://drive.google.com/file/d/1drUjps5PB0yF9PZNot5VR2yFlnxL7ZU5/view?usp=sharing

    CPU temps are 90, which I think is could be on the limit as the core speed was consistently around 1.8-2.2 - too low. I already had TurboBoost disabled.
    GPU usage is 100%, but I'm not sure if it says much. The fps is stable at around 60-70.

    I'm not sure if i7-7700hq is modern by your standards. Seems like RF2 is very heavy on my cpu. Is it all physics calculations? I wonder if other major things contribute to it, like busy waiting which could be wasting resources.
     
    Last edited: Oct 11, 2023
  13. Johnny Speed

    Johnny Speed Registered

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    I don't know if this is relevant..but how many AI cars are you using? Also graphics settings (shadows, reflections, rain ect) Your computer is better than mine, I don't have the slow down problem that you are experiencing. (I run 9 AI cars and shadows and things like that turned off)
     
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  14. Lazza

    Lazza Registered

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    I'm on an i5-8600 and CPU isn't an issue without huge fields. It's about core speed, so while your 4 cores at full speed should be fine you don't want hyperthreading to split them into 8 and drop the physics thread down to half speed (terrible simplification on my part, but you get the idea).

    (and yeah, 90 degrees doesn't sound good - at this point I guess the worlds of laptops and desktops diverge, you may have limited options to help with cooling)
     
  15. Sorry to say this, but this is information we would have needed right at the beginning as everybody (at least me) assumed you are using a desktop PC.

    90°C is too much. I bet CPU speed is reduced by BIOS, Windows whatever in order to cool down the CPU (maybe cooler is blocked, dirty etc.).

    GPU usage at 100% sounds ok, but if it would be around 95% I would say it is unlikely that you 've a GPU problem; but with 100% (as already mentioned) reduce number of AI, FX settings like shadow, special FX, road reflections and so on.

    Stable 60 fps may be a misleading information - how do you measure it?

    Also there are a lot of options consuming GPU and CPU power like "Live TV displays", motion blur, visible vehicles and so on.

    I am not quite sure, but disabling turbo boost will reduce speed of CPU cores and may not be disabling hyperthreading - but that depends a bit on your notebooks BIOS.
     
  16. szczebrzeszyn

    szczebrzeszyn Registered

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    It's a 17" gaming laptop with good cooling system. These laptops are capable of running long workloads and sustain high cpu frequency. I mentioned before I have Turbo Boost disabled to avoid higher temperatures.

    with ctrl+c and ctrl+v.

    I disabled hyperthreading and played a full race with OpenHardwareMonitor telemetry enabled. It snapshots lots of cpu/gpu telemetry once every second. I also turned around the laptop, enabling it to cool itself. That made a huge difference in terms of actual cpu frequency during the game. I also cleaned the laptop fans.

    The game still hiccups a lot. Measured frequency dipped to 800mhz a couple of times. But i am not 100% sure if that it's the cause. It's possible that intel is kicking in with it's low frequency p-state? I think if it was something else cpu would not drop to 800. When it's relatively idle it's still shows 1.5ghz.
    View attachment upload_2023-10-13_18-30-52.png
    The number of hiccups was way bigger but snapshot is taken once every second so maybe that's why there's only a couple of them here.

    TODO: try with ThrottleStop or manually change maximum cpu frequency to 70%. Also enable live telemtry to ensure that cpu frequency drop is causing game hiccups.
     
    Last edited: Oct 14, 2023
  17. szczebrzeszyn

    szczebrzeszyn Registered

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    Thank you all for the input. Rfactor 2 no longer slows down on my laptop with vsync and ThrottleStop enabled. I lowered maximum clock speed from 2.8 to 2.6 and undervolted cpu a bit. The temps are now closer to 80 celsius.
     
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