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Bug
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Resolution: Duplicate
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Normal
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None
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rhel-9.4
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None
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Moderate
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rhel-sst-virtualization-windows
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ssg_virtualization
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None
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QE ack
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False
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None
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Red Hat Enterprise Linux
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None
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None
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None
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x86_64
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Windows
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None
What were you trying to do that didn't work?
Transmitting small TCP packets continuously using the NetKVM driver led to excessive paging and packet loss.
Please provide the package NVR for which the bug is seen:
qemu-kvm-8.0.0-7.el9.x86_64
virtio-win-1.9.35-0.el9.iso
kernel-5.14.0-362.8.1.el9_3.x86_64
How reproducible:
50%
Steps to reproduce
1. Setup a Win2019 VM using virtio-net adapter on QEMU
/usr/libexec/qemu-kvm -m 17408 \ -device '{"id": "pcie-root-port-3", "port": 3, "driver": "pcie-root-port", "addr": "0x1.0x3", "bus": "pcie.0", "chassis": 4}' \ -device '{"driver": "virtio-net-pci", "mac": "9a:44:d9:4f:bb:cf", "id": "idUyryQr", "netdev": "idxarPu0", "bus": "pcie-root-port-3", "addr": "0x0"}' \ -netdev '{"id": "idxarPu0", "type": "tap", "vhost": true, "vhostfd": "16", "fd": "12"}' \{noformat}
2. Run a Python script that sends small TCP packets continuously in the host.
3. Run a Python script to receive these packets in the VM.
4. Observe the packet handling behavior at the driver level.
Expected results
Always 100% of packets received
Actual results
The reception of packets randomly stops
Additional context
The `rec.py` in the VM:
import random import socket for i in range(1, 1001): random1 = random.randint(0, 99) random2 = random.randint(0, 9999) message = "Count {}: {},{},{}".format(i, random1, '12233333', random2).encode('utf-8') sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM) sock.connect(('<Host_IP>', 8001)) sock.sendall(message) sock.close()
The `send.py` in the Host:
import socket HOST = '<Host_IP>' PORT = 8001 with socket.socket(socket.AF_INET, socket.SOCK_STREAM) as s: s.bind((HOST, PORT)) s.listen() while True: conn, addr = s.accept() with conn: print('Connected by', addr) while True: data = conn.recv(1024) if not data: break print(data) conn.sendall(data)
Upstream source: https://github.com/virtio-win/kvm-guest-drivers-windows/issues/942
- duplicates
-
RHEL-19378 netkvm: connection drop when using iperf with very short packets
- Closed