On 23/04/19 14:04, Stefan Hajnoczi wrote: >> In addition, does Virtio-scsi support Batch I/O Submission feature >> which may be able to increase the IOPS via reducing the number of >> system calls? > > I don't see obvious batching support in drivers/scsi/virtio_scsi.c. > The Linux block layer supports batching but I'm not sure if the SCSI > layer does.
I think he's referring to QEMU, in which case yes, virtio-scsi does batch I/O submission. See virtio_scsi_handle_cmd_req_prepare and virtio_scsi_handle_cmd_req_submit in hw/scsi/virtio-scsi.c, they do blk_io_plug and blk_io_unplug in order to batch I/O requests from QEMU to the host kernel. Paolo
