[zpl]

Hello, I encountered a problem while using it. I only installed the installation package for Windows Packet Filter and tested its speed using iperf3. It dropped directly from 10Gb to 2.5Gb. That’s right, I only installed the installation package and did not run any sample programs

[Vadim Smirnov]

This is probably related to Jumbo Frames. Some hardware can reach 10 Gbps only when Jumbo Frames are enabled, while the standard Windows Packet Filter driver build limits the maximum Ethernet frame size to 1514 bytes:

#ifdef JUMBO_FRAME_SUPPORTED
#define MAX_ETHER_FRAME 9014
#else
#define MAX_ETHER_FRAME 1514
#endif

So, even if no sample application is running, installing the standard driver may affect throughput on such hardware.

To enable Jumbo Frame support, the driver has to be rebuilt with JUMBO_FRAME_SUPPORTED defined.

[george456]

That’s definitely not expected. Just installing the Windows Packet Filter driver shouldn’t normally reduce your throughput from 10 Gb/s to around 2.5 Gb/s without any filtering application running.

A few things I’d check:

• Make sure the NIC driver didn’t change or get reconfigured after the installation.
• Verify that features like RSS, RSC, and Large Send Offload are still enabled, as those can have a big impact on 10 Gb performance.
• Try uninstalling the Windows Packet Filter package and rerun the same iperf3 test to confirm the performance drop is directly related.
• If possible, test with the latest version of the driver and the WFP package, as there may have been fixes since the version you’re using.

Out of curiosity, what network adapter are you using (Intel, Mellanox, Broadcom, etc.) and which version of Windows? That information might help narrow down whether it’s a driver compatibility issue or something specific to the filter driver.

[zpl]

we have identified the issue. We were previously using a virtual machine with a virtual network card, but after switching to a physical machine, this phenomenon no longer occurred. The model of the virtual network card is Red Hat VirtIO Ethernet Adapter

[Author]

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