v3:
- Add Patch 1 to avoid clobbering tx descriptor bits
- Add Patch 2 to avoid confusing tx command modes
- Exclude IP and TCP headers from large send MSS value
The rtl8139 large send offload currently does not honor the MSS value provided
by the driver. This is a problem especially when the MTU is small because IP
fragmentation occurs and leads to poor performance.
These patches make use of the large send MSS value.
I have done basic testing by running the following Python code inside the
guest:
import socket
s = socket.socket()
s.connect(('10.0.2.2', 1234))
buf = b'A' * 4096
s.send(buf)
The device sees a 4150 byte tx descriptor that results in the transmission of 3
Ethernet frames with sizes of 1514, 1514, and 1230 bytes when the large send
MSS value is 1460 bytes.
Stefan Hajnoczi (3):
rtl8139: avoid clobbering tx descriptor bits
rtl8139: keep Tx command mode 0 and 1 separate
rtl8139: honor large send MSS value
hw/net/rtl8139.c | 47 ++++++++++++++++++++++++-----------------------
1 file changed, 24 insertions(+), 23 deletions(-)
--
2.38.1
