mirror of
https://github.com/qemu/qemu.git
synced 2025-10-31 12:07:31 +00:00
9445e1e15e
Automatically size the number of virtio-blk-pci request virtqueues to match the number of vCPUs. Other transports continue to default to 1 request virtqueue. A 1:1 virtqueue:vCPU mapping ensures that completion interrupts are handled on the same vCPU that submitted the request. No IPI is necessary to complete an I/O request and performance is improved. The maximum number of MSI-X vectors and virtqueues limit are respected. Performance improves from 78k to 104k IOPS on a 32 vCPU guest with 101 virtio-blk-pci devices (ioengine=libaio, iodepth=1, bs=4k, rw=randread with NVMe storage). Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Cornelia Huck <cohuck@redhat.com> Reviewed-by: Pankaj Gupta <pankaj.gupta.linux@gmail.com> Message-Id: <20200818143348.310613-7-stefanha@redhat.com> Reviewed-by: Michael S. Tsirkin <mst@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
94 lines
2.1 KiB
C
94 lines
2.1 KiB
C
/*
|
|
* Virtio Block Device
|
|
*
|
|
* Copyright IBM, Corp. 2007
|
|
*
|
|
* Authors:
|
|
* Anthony Liguori <aliguori@us.ibm.com>
|
|
*
|
|
* This work is licensed under the terms of the GNU GPL, version 2. See
|
|
* the COPYING file in the top-level directory.
|
|
*
|
|
*/
|
|
|
|
#ifndef QEMU_VIRTIO_BLK_H
|
|
#define QEMU_VIRTIO_BLK_H
|
|
|
|
#include "standard-headers/linux/virtio_blk.h"
|
|
#include "hw/virtio/virtio.h"
|
|
#include "hw/block/block.h"
|
|
#include "sysemu/iothread.h"
|
|
#include "sysemu/block-backend.h"
|
|
|
|
#define TYPE_VIRTIO_BLK "virtio-blk-device"
|
|
#define VIRTIO_BLK(obj) \
|
|
OBJECT_CHECK(VirtIOBlock, (obj), TYPE_VIRTIO_BLK)
|
|
|
|
/* This is the last element of the write scatter-gather list */
|
|
struct virtio_blk_inhdr
|
|
{
|
|
unsigned char status;
|
|
};
|
|
|
|
#define VIRTIO_BLK_AUTO_NUM_QUEUES UINT16_MAX
|
|
|
|
struct VirtIOBlkConf
|
|
{
|
|
BlockConf conf;
|
|
IOThread *iothread;
|
|
char *serial;
|
|
uint32_t request_merging;
|
|
uint16_t num_queues;
|
|
uint16_t queue_size;
|
|
bool seg_max_adjust;
|
|
uint32_t max_discard_sectors;
|
|
uint32_t max_write_zeroes_sectors;
|
|
bool x_enable_wce_if_config_wce;
|
|
};
|
|
|
|
struct VirtIOBlockDataPlane;
|
|
|
|
struct VirtIOBlockReq;
|
|
typedef struct VirtIOBlock {
|
|
VirtIODevice parent_obj;
|
|
BlockBackend *blk;
|
|
void *rq;
|
|
QEMUBH *bh;
|
|
VirtIOBlkConf conf;
|
|
unsigned short sector_mask;
|
|
bool original_wce;
|
|
VMChangeStateEntry *change;
|
|
bool dataplane_disabled;
|
|
bool dataplane_started;
|
|
struct VirtIOBlockDataPlane *dataplane;
|
|
uint64_t host_features;
|
|
size_t config_size;
|
|
} VirtIOBlock;
|
|
|
|
typedef struct VirtIOBlockReq {
|
|
VirtQueueElement elem;
|
|
int64_t sector_num;
|
|
VirtIOBlock *dev;
|
|
VirtQueue *vq;
|
|
struct virtio_blk_inhdr *in;
|
|
struct virtio_blk_outhdr out;
|
|
QEMUIOVector qiov;
|
|
size_t in_len;
|
|
struct VirtIOBlockReq *next;
|
|
struct VirtIOBlockReq *mr_next;
|
|
BlockAcctCookie acct;
|
|
} VirtIOBlockReq;
|
|
|
|
#define VIRTIO_BLK_MAX_MERGE_REQS 32
|
|
|
|
typedef struct MultiReqBuffer {
|
|
VirtIOBlockReq *reqs[VIRTIO_BLK_MAX_MERGE_REQS];
|
|
unsigned int num_reqs;
|
|
bool is_write;
|
|
} MultiReqBuffer;
|
|
|
|
bool virtio_blk_handle_vq(VirtIOBlock *s, VirtQueue *vq);
|
|
void virtio_blk_process_queued_requests(VirtIOBlock *s, bool is_bh);
|
|
|
|
#endif
|