g_slice_new(VirtIOBlockReq), its free pair and access the instance is a bit slow since sizeof(VirtIOBlockReq) takes more than 40KB, so use object pool to speed up its allocation and release.
With this patch, ~5%-10% throughput improvement is observed in the VM based on server. Signed-off-by: Ming Lei <ming....@canonical.com> --- hw/block/dataplane/virtio-blk.c | 12 ++++++++++++ hw/block/virtio-blk.c | 13 +++++++++++-- include/hw/virtio/virtio-blk.h | 2 ++ 3 files changed, 25 insertions(+), 2 deletions(-) diff --git a/hw/block/dataplane/virtio-blk.c b/hw/block/dataplane/virtio-blk.c index d6ba65c..c9a8cc2 100644 --- a/hw/block/dataplane/virtio-blk.c +++ b/hw/block/dataplane/virtio-blk.c @@ -24,6 +24,8 @@ #include "hw/virtio/virtio-bus.h" #include "qom/object_interfaces.h" +#define REQ_POOL_SZ 128 + struct VirtIOBlockDataPlane { bool started; bool starting; @@ -50,6 +52,10 @@ struct VirtIOBlockDataPlane { Error *blocker; void (*saved_complete_request)(struct VirtIOBlockReq *req, unsigned char status); + + VirtIOBlockReq reqs[REQ_POOL_SZ]; + void *free_reqs[REQ_POOL_SZ]; + ObjPool req_pool; }; /* Raise an interrupt to signal guest, if necessary */ @@ -235,6 +241,10 @@ void virtio_blk_data_plane_start(VirtIOBlockDataPlane *s) return; } + vblk->obj_pool = &s->req_pool; + obj_pool_init(vblk->obj_pool, s->reqs, s->free_reqs, + sizeof(VirtIOBlockReq), REQ_POOL_SZ); + /* Set up guest notifier (irq) */ if (k->set_guest_notifiers(qbus->parent, 1, true) != 0) { fprintf(stderr, "virtio-blk failed to set guest notifier, " @@ -291,6 +301,8 @@ void virtio_blk_data_plane_stop(VirtIOBlockDataPlane *s) aio_context_release(s->ctx); + vblk->obj_pool = NULL; + /* Sync vring state back to virtqueue so that non-dataplane request * processing can continue when we disable the host notifier below. */ diff --git a/hw/block/virtio-blk.c b/hw/block/virtio-blk.c index c241c50..2a11bc4 100644 --- a/hw/block/virtio-blk.c +++ b/hw/block/virtio-blk.c @@ -31,7 +31,11 @@ VirtIOBlockReq *virtio_blk_alloc_request(VirtIOBlock *s) { - VirtIOBlockReq *req = g_slice_new(VirtIOBlockReq); + VirtIOBlockReq *req = obj_pool_get(s->obj_pool); + + if (!req) { + req = g_slice_new(VirtIOBlockReq); + } req->dev = s; req->qiov.size = 0; req->next = NULL; @@ -41,7 +45,11 @@ VirtIOBlockReq *virtio_blk_alloc_request(VirtIOBlock *s) void virtio_blk_free_request(VirtIOBlockReq *req) { if (req) { - g_slice_free(VirtIOBlockReq, req); + if (obj_pool_has_obj(req->dev->obj_pool, req)) { + obj_pool_put(req->dev->obj_pool, req); + } else { + g_slice_free(VirtIOBlockReq, req); + } } } @@ -801,6 +809,7 @@ static void virtio_blk_instance_init(Object *obj) { VirtIOBlock *s = VIRTIO_BLK(obj); + s->obj_pool = NULL; object_property_add_link(obj, "iothread", TYPE_IOTHREAD, (Object **)&s->blk.iothread, qdev_prop_allow_set_link_before_realize, diff --git a/include/hw/virtio/virtio-blk.h b/include/hw/virtio/virtio-blk.h index afb7b8d..49ac234 100644 --- a/include/hw/virtio/virtio-blk.h +++ b/include/hw/virtio/virtio-blk.h @@ -18,6 +18,7 @@ #include "hw/block/block.h" #include "sysemu/iothread.h" #include "block/block.h" +#include "qemu/obj_pool.h" #define TYPE_VIRTIO_BLK "virtio-blk-device" #define VIRTIO_BLK(obj) \ @@ -135,6 +136,7 @@ typedef struct VirtIOBlock { Notifier migration_state_notifier; struct VirtIOBlockDataPlane *dataplane; #endif + ObjPool *obj_pool; } VirtIOBlock; typedef struct MultiReqBuffer { -- 1.7.9.5