It is pretty common for the DPDK applications to be deployed in semi-pipeline model. In these models, a small number of cores (typically 1) are designated as I/O cores. The I/O cores work on receiving and transmitting packets from the NIC and several packet processing cores. The IO core and the packet processing cores exchange the packets over a ring. Typically, such applications receive the mbufs in a temporary array and copy the mbufs on to the ring. Depending on the requirements the packets could be copied in batches of 32, 64 etc resulting in 256B, 512B etc memory copy.
The zero copy APIs help avoid intermediate copies by exposing the space on the ring directly to the application. v4: 1) Fixed multiple pointer issues 2) Added documentation v3: 1) Changed the name of the APIs to 'zero-copy (zc)' 2) Made the address calculation simpler 3) Structure to return the data to the user is aligned on cache line boundary. 4) Added functional and stress test cases v2: changed the patch to use the SP-SC and HTS modes v1: Initial version Honnappa Nagarahalli (8): lib/ring: add zero copy APIs test/ring: move common function to header file test/ring: add functional tests for zero copy APIs test/ring: add stress tests for zero copy APIs doc/ring: add zero copy peek APIs test/ring: fix the memory dump size test/ring: remove unnecessary braces test/ring: user uintptr_t instead of unsigned long app/test/meson.build | 2 + app/test/test_ring.c | 209 +++++++++- app/test/test_ring.h | 67 ++- app/test/test_ring_mt_peek_stress_zc.c | 56 +++ app/test/test_ring_st_peek_stress_zc.c | 65 +++ app/test/test_ring_stress.c | 6 + app/test/test_ring_stress.h | 2 + app/test/test_ring_stress_impl.h | 2 +- doc/guides/prog_guide/ring_lib.rst | 41 ++ doc/guides/rel_notes/release_20_11.rst | 9 + lib/librte_ring/meson.build | 1 + lib/librte_ring/rte_ring_elem.h | 1 + lib/librte_ring/rte_ring_peek_zc.h | 546 +++++++++++++++++++++++++ 13 files changed, 988 insertions(+), 19 deletions(-) create mode 100644 app/test/test_ring_mt_peek_stress_zc.c create mode 100644 app/test/test_ring_st_peek_stress_zc.c create mode 100644 lib/librte_ring/rte_ring_peek_zc.h -- 2.17.1
