Option for "GPU Context Switch Trace" is missing in Windows

I am running Nsight Systems 2021.2.1 as admin on a Windows 10 system with a GV100, driver version 472.12.

The Nsight Systems documentation mentions an option for tracing GPU context switches:

  • This can be set via the GUI, but it is mentioned only for Linux hosts. When will it also be available for Windows?
  • This can be set as a command line parameter (–gpuctxsw). However, it seems not be supported, as nsys reports back: “unrecognised option ‘–gpuctxsw’”. Is this a bug or the flag is not supported via the command line either?

Any other way to profile GPU context switches on a Windows host machine?


Hi ancah,
GPU context switch tracing is available both for GUI and CLI on Windows, with Nsight Systems version 2021.4. You can download the latest version here.

Hi ztasoulas,

Thanks for the quick reply.

Actually I had installed Nsight 2021.4 already, but I cannot use it. It fails when selecting local host as the target, even if I say yes when getting those popups that ask about allowing nsys to make changes to this computer:
“[Error] Failed to launch daemon
Failed to launch daemon executable on target.
Please kill all running instances of nsys.exe manually or reboot the target.”

I tried rebooting, reinstalling Nsight Systems or running Nsight as Admin, none works.

Any idea how to fix this?

Thanks a lot!

Update: it seems that Nsight Systems 2021.4 only works when the GPU is in TCC mode, I posted about it here.

When running Nsight Systems GUI 2021.4 with the GPU in WDDM mode, I don’t see any option to trace GPU context switches. These are the only options:

How can I use/control the GPU context switch tracing when running Nsight Systems on Windows?

Update: “Collect GPU context switch trace” option appeared after reinstalling yet again the driver, version 472.12. The only thing I did differently was to install the driver first and then install Nsight Systems. Apart from that, Nsight Systems still doesn’t work when the GPU is in TCC mode, as posted here.