Prepare the AF_XDP selftests test framework code for the upcoming
multi-buffer support in AF_XDP. This so that the multi-buffer patch
set does not become way too large. In that upcoming patch set, we are
only including the multi-buffer tests together with any framework
code that depends on the new options bit introduced in the AF_XDP
multi-buffer implementation itself.
Currently, the test framework is based on the premise that a packet
consists of a single fragment and thus occupies a single buffer and a
single descriptor. Multi-buffer breaks this assumption, as that is the
whole purpose of it. Now, a packet can consist of multiple buffers and
therefore consume multiple descriptors.
The patch set starts with some clean-ups and simplifications followed
by patches that make sure that the current code works even when a
packet occupies multiple buffers. The actual code for sending and
receiving multi-buffer packets will be included in the AF_XDP
multi-buffer patch set as it depends on a new bit being used in the
options field of the descriptor.
Patch set anatomy:
1: The XDP program was unnecessarily changed many times. Fixes this.
2: There is no reason to generate a full UDP/IPv4 packet as it is
never used. Simplify the code by just generating a valid Ethernet
frame.
3: Introduce a more complicated payload pattern that can detect
fragments out of bounds in a multi-buffer packet and other errors
found in single-fragment packets.
4: As a convenience, dump the content of the faulty packet at error.
5: To simplify the code, make the usage of the packet stream for Tx
and Rx more similar.
6: Store the offset of the packet in the buffer in the struct pkt
definition instead of the address in the umem itself and introduce
a simple buffer allocator. The address only made sense when all
packets consumed a single buffer. Now, we do not know beforehand
how many buffers a packet will consume, so we instead just allocate
a buffer from the allocator and specify the offset within that
buffer.
7: Test for huge pages only once instead of before each test that needs it.
8: Populate the fill ring based on how many frags are needed for each
packet.
9: Change the data generation code so it can generate data for
multi-buffer packets too.
10: Adjust the packet pacing algorithm so that it can cope with
multi-buffer packets. The pacing algorithm is present so that Tx
does not send too many packets/frames to Rx that it starts to drop
packets. That would ruin the tests.
v1 -> v2:
* Fixed spelling error in patch #6 [Simon]
* Fixed compilation error with llvm in patch #7 [Daniel]
Thanks: Magnus
Magnus Karlsson (10):
selftests/xsk: do not change XDP program when not necessary
selftests/xsk: generate simpler packets with variable length
selftests/xsk: add varying payload pattern within packet
selftests/xsk: dump packet at error
selftests/xsk: add packet iterator for tx to packet stream
selftests/xsk: store offset in pkt instead of addr
selftests/xsx: test for huge pages only once
selftests/xsk: populate fill ring based on frags needed
selftests/xsk: generate data for multi-buffer packets
selftests/xsk: adjust packet pacing for multi-buffer support
tools/testing/selftests/bpf/test_xsk.sh | 10 +-
tools/testing/selftests/bpf/xsk.h | 5 +
tools/testing/selftests/bpf/xskxceiver.c | 771 +++++++++++------------
tools/testing/selftests/bpf/xskxceiver.h | 31 +-
4 files changed, 379 insertions(+), 438 deletions(-)
base-commit: 108598c39eefbedc9882273ac0df96127a629220
--
2.34.1
