Commit c99495ac authored by Peter Lieven's avatar Peter Lieven Committed by Kevin Wolf
Browse files

virtio-blk: add a knob to disable request merging 



this adds a knob to disable request merging for debugging or benchmarks if dedired.

Signed-off-by: default avatarPeter Lieven <pl@kamp.de>
Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
parent 95f7142a

hw/block/virtio-blk.c

+4 −1
Original line number Diff line number Diff line
@@ -531,7 +531,8 @@ void virtio_blk_handle_request(VirtIOBlockReq *req, MultiReqBuffer *mrb) 
        /* merge would exceed maximum number of requests or IO direction

         * changes */

        if (mrb->num_reqs > 0 && (mrb->num_reqs == VIRTIO_BLK_MAX_MERGE_REQS ||

                                  is_write != mrb->is_write)) {

                                  is_write != mrb->is_write ||

                                  !req->dev->conf.request_merging)) {

            virtio_blk_submit_multireq(req->dev->blk, mrb);

        }
@@ -950,6 +951,8 @@ static Property virtio_blk_properties[] = { 
#ifdef __linux__

    DEFINE_PROP_BIT("scsi", VirtIOBlock, conf.scsi, 0, true),

#endif

    DEFINE_PROP_BIT("request-merging", VirtIOBlock, conf.request_merging, 0,

                    true),

    DEFINE_PROP_BIT("x-data-plane", VirtIOBlock, conf.data_plane, 0, false),

    DEFINE_PROP_END_OF_LIST(),

};

include/hw/virtio/virtio-blk.h

+1 −0
Original line number Diff line number Diff line
@@ -113,6 +113,7 @@ struct VirtIOBlkConf 
    uint32_t scsi;

    uint32_t config_wce;

    uint32_t data_plane;

    uint32_t request_merging;

};



struct VirtIOBlockDataPlane;