Hi all: This RFC implement packed ring layout. The code were tested with Tiwei's RFC V3 ahttps://lkml.org/lkml/2018/4/25/34. Some fixups and tweaks were needed on top of Tiwei's code to make it run for event index.
Pktgen reports about 20% improvement on PPS (event index is off). More testing is ongoing. Notes for tester: - Start from this version, vhost need qemu co-operation to work correctly. Or you can comment out the packed specific code for GET/SET_VRING_BASE. Changes from V3: - Fix math on event idx checking - Sync last avail wrap counter through GET/SET_VRING_BASE - remove desc_event prefix in the driver/device structure Changes from V2: - do not use & in checking desc_event_flags - off should be most significant bit - remove the workaround of mergeable buffer for dpdk prototype - id should be in the last descriptor in the chain - keep _F_WRITE for write descriptor when adding used - device flags updating should use ADDR_USED type - return error on unexpected unavail descriptor in a chain - return false in vhost_ve_avail_empty is descriptor is available - track last seen avail_wrap_counter - correctly examine available descriptor in get_indirect_packed() - vhost_idx_diff should return u16 instead of bool Changes from V1: - Refactor vhost used elem code to avoid open coding on used elem - Event suppression support (compile test only). - Indirect descriptor support (compile test only). - Zerocopy support. - vIOMMU support. - SCSI/VSOCK support (compile test only). - Fix several bugs Jason Wang (8): vhost: move get_rx_bufs to vhost.c vhost: hide used ring layout from device vhost: do not use vring_used_elem vhost_net: do not explicitly manipulate vhost_used_elem vhost: vhost_put_user() can accept metadata type virtio: introduce packed ring defines vhost: packed ring support vhost: event suppression for packed ring drivers/vhost/net.c | 136 ++---- drivers/vhost/scsi.c | 62 +-- drivers/vhost/vhost.c | 861 ++++++++++++++++++++++++++++++++----- drivers/vhost/vhost.h | 47 +- drivers/vhost/vsock.c | 42 +- include/uapi/linux/virtio_config.h | 9 + include/uapi/linux/virtio_ring.h | 32 ++ 7 files changed, 928 insertions(+), 261 deletions(-) -- 2.7.4
