SendPacket latency question

[lk-davidegironi]

SendPacket latency question

[kayoub5]

@lk-davidegironi

• Npcap version? Possibly related to nmap/npcap#619 Npcap 1.20 have better sending performance as far as I have seen.
• Any antivirus software on the PC?
• Try to change GC mode https://learn.microsoft.com/en-us/dotnet/core/runtime-config/garbage-collector#flavors-of-garbage-collection

[lk-davidegironi]

Thanks @kayoub5 for your interest

• Npcap version: 1.71. I try with other versions 1.60, 1.72, 1.55... same thing
• ESET32 antivirus + firewall (disabling does not makes difference). Try with a laptop i7 based with Realtek board, same behaviour
• No luck changing GC mode

One more thing I've try is using an Intel i210 NIC board. Nothing changed.
I'll keep you updated... in case I found something usefull.

[kayoub5]

• Try Npcap 1.20 or 1.10
• Disabling anti-virus does not remove its performance effects, you have to actually uninstall it (and reboot for changes to take effects)
• Is the cable full duplex or half duplex?

[kayoub5]

other things to consider:

• thread and process priority
• using different device object for sending and receiving
• disable ipv4 and ipv6 from device properties

[lk-davidegironi]

Thank you @kayoub5

• Try Npcap 1.20 and all the version newer than 1.10 = No effects
• Disabling anti-virus does not remove its performance effects, you have to actually uninstall it (and reboot for changes to take effects) = Done on the other laptop PC, no effects
• Is the cable full duplex or half duplex? = Full duplex, also I've try other cables. No effects
• thread and process priority = Although my process is set to RealTime (ProcessPriorityClass.RealTime) it starts in High priority. Changing it by hand on the Task Manager does not affect performances on my i7. I makes some small difference only if i take down to Normal level
• using different device object for sending and receiving = Tried on Realtek RTL8111E and Intel i210, makes no different
• disable ipv4 and ipv6 from device properties = In both the devices I've try, all is disabled except "Npcap Packet Driver" and "Link-Layer Topology Discovery Responder"

I'm wondering if a plain c/c++ software could help me for tests.

[lk-davidegironi]

Something interesting I've noticed:
.NET 5.0, .NET Core 3.0 and 3.1 has almost the same performance
.NET 6.0 or .NET 7.0 is almost half the performance of the above

[kayoub5]

I'm wondering if a plain c/c++ software could help me for tests.

Possible, I would recommend using a different driver (like winpktfilter) or a kernel bypass using dpdk if that does not help.