On Thu, Nov 17, 2022 at 11:55:51AM -0500, Stefan Hajnoczi wrote:
> 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
> Thanks, applied to qemu.git/master! Stefan
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