qemu/hw/virtio
Ilya Maximets 850cd20b07 virtio: use shadow_avail_idx while checking number of heads
We do not need the most up to date number of heads, we only want to
know if there is at least one.

Use shadow variable as long as it is not equal to the last available
index checked.  This avoids expensive qatomic dereference of the
RCU-protected memory region cache as well as the memory access itself.

The change improves performance of the af-xdp network backend by 2-3%.

Signed-off-by: Ilya Maximets <i.maximets@ovn.org>
Message-Id: <20230927135157.2316982-1-i.maximets@ovn.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
2023-10-04 18:15:06 -04:00
..
Kconfig virtio-md-pci: New parent type for virtio-mem-pci and virtio-pmem-pci 2023-07-12 09:27:25 +02:00
meson.build virtio: add vhost-user-base and a generic vhost-user-device 2023-10-04 04:54:04 -04:00
trace-events vdpa: export vhost_vdpa_set_vring_ready 2023-10-04 04:54:19 -04:00
trace.h
vdpa-dev-pci.c vdpa: add vdpa-dev-pci support 2022-12-21 06:35:28 -05:00
vdpa-dev.c vdpa: move vhost_vdpa_set_vring_ready to the caller 2023-10-04 04:54:21 -04:00
vhost-backend.c vhost: add method vhost_set_vring_err 2022-06-27 18:53:18 -04:00
vhost-iova-tree.c util: accept iova_tree_remove_parameter by value 2022-09-02 10:22:39 +08:00
vhost-iova-tree.h util: accept iova_tree_remove_parameter by value 2022-09-02 10:22:39 +08:00
vhost-scsi-pci.c
vhost-shadow-virtqueue.c vhost: Add count argument to vhost_svq_poll() 2023-10-04 04:54:23 -04:00
vhost-shadow-virtqueue.h vhost: Add count argument to vhost_svq_poll() 2023-10-04 04:54:23 -04:00
vhost-stub.c vhost: register and change IOMMU flag depending on Device-TLB state 2023-07-10 15:07:50 -04:00
vhost-user-blk-pci.c
vhost-user-device-pci.c virtio: add vhost-user-base and a generic vhost-user-device 2023-10-04 04:54:04 -04:00
vhost-user-device.c hw/virtio: add config support to vhost-user-device 2023-10-04 04:54:05 -04:00
vhost-user-fs-pci.c
vhost-user-fs.c hw/virtio: fix typo in VIRTIO_CONFIG_IRQ_IDX comments 2023-07-10 18:59:32 -04:00
vhost-user-gpio-pci.c hw/virtio: add vhost-user-gpio-pci boilerplate 2022-10-07 09:41:51 -04:00
vhost-user-gpio.c qmp: update virtio feature maps, vhost-user-gpio introspection 2023-10-04 04:54:26 -04:00
vhost-user-i2c-pci.c
vhost-user-i2c.c virtio: i2c: Check notifier helpers for VIRTIO_CONFIG_IRQ_IDX 2023-04-24 22:56:55 -04:00
vhost-user-input-pci.c
vhost-user-rng-pci.c
vhost-user-rng.c vhost-user-rng: Back up vqs before cleaning up vhost_dev 2023-03-02 03:10:47 -05:00
vhost-user-scmi-pci.c hw/virtio: Add vhost-user-scmi-pci boilerplate 2023-07-10 16:17:08 -04:00
vhost-user-scmi.c hw/virtio: Add a protection against duplicate vu_scmi_stop calls 2023-08-03 16:06:49 -04:00
vhost-user-scsi-pci.c
vhost-user-vsock-pci.c
vhost-user-vsock.c hw/virtio: introduce virtio_device_should_start 2022-11-07 14:08:18 -05:00
vhost-user.c vhost-user: move VhostUserProtocolFeature definition to header file 2023-10-04 04:54:28 -04:00
vhost-vdpa.c vdpa: move vhost_vdpa_set_vring_ready to the caller 2023-10-04 04:54:21 -04:00
vhost-vsock-common.c hw/virtio: fix typo in VIRTIO_CONFIG_IRQ_IDX comments 2023-07-10 18:59:32 -04:00
vhost-vsock-pci.c
vhost-vsock.c hw/virtio: introduce virtio_device_should_start 2022-11-07 14:08:18 -05:00
vhost.c vhost: fix the fd leak 2023-08-03 16:06:49 -04:00
virtio-9p-pci.c
virtio-balloon-pci.c
virtio-balloon.c hw: replace most qemu_bh_new calls with qemu_bh_new_guarded 2023-04-28 11:31:54 +02:00
virtio-blk-pci.c
virtio-bus.c virtio: stop ioeventfd on reset 2022-06-14 16:50:30 +02:00
virtio-config-io.c hw/virtio: Extract config read/write accessors to virtio-config-io.c 2022-12-21 07:32:24 -05:00
virtio-crypto-pci.c
virtio-crypto.c hw/other: spelling fixes 2023-09-21 11:31:16 +03:00
virtio-hmp-cmds.c virtio: Move HMP commands from monitor/ to hw/virtio/ 2023-02-04 07:56:54 +01:00
virtio-input-host-pci.c
virtio-input-pci.c virtio-input-pci: add virtio-multitouch-pci 2023-05-28 13:08:25 +04:00
virtio-iommu-pci.c hw/virtio/virtio-iommu-pci: Enforce the device is plugged on the root bus 2022-11-07 13:12:19 -05:00
virtio-iommu.c virtio-iommu: Standardize granule extraction and formatting 2023-08-03 16:06:49 -04:00
virtio-md-pci.c virtio-md-pci: Support unplug requests for compatible devices 2023-07-12 09:27:30 +02:00
virtio-mem-pci.c virtio-mem-pci: Device unplug support 2023-07-12 09:27:32 +02:00
virtio-mem-pci.h virtio-md-pci: New parent type for virtio-mem-pci and virtio-pmem-pci 2023-07-12 09:27:25 +02:00
virtio-mem.c hw/other: spelling fixes 2023-09-21 11:31:16 +03:00
virtio-mmio.c virtio: refresh vring region cache after updating a virtqueue size 2023-04-21 03:08:21 -04:00
virtio-net-pci.c
virtio-pci.c virtio-pci: add handling of PCI ATS and Device-TLB enable/disable 2023-05-19 10:30:46 -04:00
virtio-pmem-pci.c virtio-md-pci: New parent type for virtio-mem-pci and virtio-pmem-pci 2023-07-12 09:27:25 +02:00
virtio-pmem-pci.h virtio-md-pci: New parent type for virtio-mem-pci and virtio-pmem-pci 2023-07-12 09:27:25 +02:00
virtio-pmem.c thread-pool: avoid passing the pool parameter every time 2023-04-25 13:17:28 +02:00
virtio-qmp.c vhost-user: move VhostUserProtocolFeature definition to header file 2023-10-04 04:54:28 -04:00
virtio-qmp.h qmp: remove virtio_list, search QOM tree instead 2023-10-04 04:54:24 -04:00
virtio-rng-pci.c virtio-rng-pci: Allow setting nvectors, so we can use MSI-X 2022-11-07 13:12:20 -05:00
virtio-rng.c
virtio-scsi-pci.c
virtio-serial-pci.c
virtio-stub.c qmp: add QMP command x-query-virtio-queue-element 2022-10-09 16:38:45 -04:00
virtio.c virtio: use shadow_avail_idx while checking number of heads 2023-10-04 18:15:06 -04:00