dataplane: add virtio-blk data plane code

virtio-blk-data-plane is a subset implementation of virtio-blk.  It only
handles read, write, and flush requests.  It does this using a dedicated
thread that executes an epoll(2)-based event loop and processes I/O
using Linux AIO.

This approach performs very well but can be used for raw image files
only.  The number of IOPS achieved has been reported to be several times
higher than the existing virtio-blk implementation.

Eventually it should be possible to unify virtio-blk-data-plane with the
main body of QEMU code once the block layer and hardware emulation is
able to run outside the global mutex.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
This commit is contained in:
Stefan Hajnoczi 2012-11-14 15:39:30 +01:00
parent 8a873ba780
commit e72f66a0a2
5 changed files with 502 additions and 1 deletions

View file

@ -98,6 +98,12 @@ virtio_blk_rw_complete(void *req, int ret) "req %p ret %d"
virtio_blk_handle_write(void *req, uint64_t sector, size_t nsectors) "req %p sector %"PRIu64" nsectors %zu"
virtio_blk_handle_read(void *req, uint64_t sector, size_t nsectors) "req %p sector %"PRIu64" nsectors %zu"
# hw/dataplane/virtio-blk.c
virtio_blk_data_plane_start(void *s) "dataplane %p"
virtio_blk_data_plane_stop(void *s) "dataplane %p"
virtio_blk_data_plane_process_request(void *s, unsigned int out_num, unsigned int in_num, unsigned int head) "dataplane %p out_num %u in_num %u head %u"
virtio_blk_data_plane_complete_request(void *s, unsigned int head, int ret) "dataplane %p head %u ret %d"
# hw/dataplane/vring.c
vring_setup(uint64_t physical, void *desc, void *avail, void *used) "vring physical %#"PRIx64" desc %p avail %p used %p"