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[Qemu-devel] [PATCH 07/15] dataplane: use object pool to speed up alloca
From: |
Ming Lei |
Subject: |
[Qemu-devel] [PATCH 07/15] dataplane: use object pool to speed up allocation for virtio blk request |
Date: |
Wed, 30 Jul 2014 19:39:40 +0800 |
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% throughput improvement is observed in the VM
based on server.
Signed-off-by: Ming Lei <address@hidden>
---
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 2093e4a..828fe99 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;
@@ -51,6 +53,10 @@ 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 */
@@ -238,6 +244,10 @@ 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, "
@@ -298,6 +308,8 @@ void virtio_blk_data_plane_stop(VirtIOBlockDataPlane *s)
aio_context_release(s->ctx);
+ vblk->obj_pool = NULL;
+
if (s->raw_format) {
qemu_aio_set_bypass_co(s->ctx, false);
}
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
[Qemu-devel] [PATCH 02/15] qemu aio: prepare for supporting selective bypass coroutine, Ming Lei, 2014/07/30
[Qemu-devel] [PATCH 03/15] block: support to bypass qemu coroutinue, Ming Lei, 2014/07/30
[Qemu-devel] [PATCH 04/15] Revert "raw-posix: drop raw_get_aio_fd() since it is no longer used", Ming Lei, 2014/07/30
[Qemu-devel] [PATCH 05/15] dataplane: enable selective bypassing coroutine, Ming Lei, 2014/07/30
[Qemu-devel] [PATCH 06/15] qemu/obj_pool.h: introduce object allocation pool, Ming Lei, 2014/07/30
[Qemu-devel] [PATCH 07/15] dataplane: use object pool to speed up allocation for virtio blk request,
Ming Lei <=
[Qemu-devel] [PATCH 08/15] virtio: decrease size of VirtQueueElement, Ming Lei, 2014/07/30