this series adds the long missing multiread support to virtio-blk. some remarks: - i introduced rd_merged and wr_merged block accounting stats to blockstats as a generic interface which can be set from any driver that will introduce multirequst merging in the future. - the knob to disable request merging is not yet there. I would add it to the device properties also as a generic interface to have the same switch on for any driver that might introduce request merging in the future - there is cleanup and iotest adjustion missing.
RFC v1->v2: - completed Patch 1 by the example in qmp-commands.hx [Eric] - used bool for merge in Patch 4 [Max] - fixed a few typos in the commit msg of Patch 4 [Max] - do not start merging and directly pass req[0]->qiov in case of num_reqs == 1 - avoid allocating memory for the multireq [Kevin] - do not import block_int.h and add appropiate iface to block-backend [Kevin] - removed debug output and added trace event for multireq [Kevin] - fixed alloc hint for the merge qiov [Kevin] - currently did not split virtio_submit_multireq into rw code since the redundant code would now be much bigger part than in the original patch. - added a merge_qiov to VirtioBlockRequest. Abusing the qiov was not possible because it is initialized externally with guest memory [Kevin] - added a pointer to VirtioBlockRequest to create a linked list of VirtioBlockBlockRequests. This list is used to complete all requests belonging to a multireq [Kevin] Peter Lieven (4): block: add accounting for merged requests hw/virtio-blk: add a constant for max number of merged requests block-backend: expose bs->bl.max_transfer_length virtio-blk: introduce multiread block.c | 2 + block/accounting.c | 7 ++ block/block-backend.c | 5 + block/qapi.c | 2 + hmp.c | 6 +- hw/block/dataplane/virtio-blk.c | 10 +- hw/block/virtio-blk.c | 219 ++++++++++++++++++++++----------------- include/block/accounting.h | 3 + include/hw/virtio/virtio-blk.h | 23 ++-- include/sysemu/block-backend.h | 1 + qapi/block-core.json | 9 +- qmp-commands.hx | 22 +++- trace-events | 1 + 13 files changed, 197 insertions(+), 113 deletions(-) -- 1.7.9.5
