Pool rtl8139 performance

[kallisti5]

rtl8139 performance is extremely random.

Host system:

libvirtd + kvm on Linux

Control:

Prepare a Haiku VM.

• hrev51540
• 4 cores
• virtio disk
• Network card. "Source Mode: Bridge". Driver: e1000

Download a kernel from kernel.org. Observe download speed. Should be consistent limited by your local internet connection.

Test:

• Power off vm
• Change network card to the "rtl8139" driver.
• Boot.

Download a kernel from kernel.org. Observe download speed.

In my tests, the download starts strong at 7MB/s, but then suddenly drops to 230KB/s after somewhere between 7% - 60% downloaded.

Other observations:

• CPU
  • With rtl8139, during speed reduction, one core is pegged at 100%.
  • With e1000, all cores have low even load.
• Input
  • With rtl8139, during speed reduction, mouse movement freezes up
  • With e1000, mouse movement remains normal.

Given the observations above, this issue could be related to an interrupt storm.