Previously we allocated `sizeof(struct ring) + size`. This patch
allocates `sizeof(struct ring)` and then `size` for the payload
separately. Hopefully the payload will be better aligned.
Signed-off-by: David Scott <dave.scott@docker.com>
This patch adds a simple ring buffer implementation and uses it to buffer
the reads and writes to/from the AF_HYPERV socket and tap file descriptor.
This removes the need to perform small reads and writes for the per-packet
headers and allows a read on the Hyper-V socket to block at the same time
as a write to the tap device (and vice-versa)
The configuration in the init.d script is:
- a max message size (individual read or write) of 8192. Experimentally
this seems to be the largest completely reliable size across the Windows
versions we can support. Messages of length 16384 sometimes fail.
- a buffer size of 256KiB in each direction.
Single stream TCP throughput as measured by iperf increases modestly, by
another 100Mbit/sec.
Signed-off-by: David Scott <dave.scott@docker.com>
