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vmm: Cache whether io_uring is supported in DeviceManager

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Probing for whether the io_uring is supported is time consuming so cache
this value if it is known to reduce the cost for secondary block devices
that are added.

Before:

cloud-hypervisor: 3.988896ms: <vmm> INFO:vmm/src/device_manager.rs:1901 -- Creating virtio-block device: DiskConfig { path: Some("/home/rob/workloads/focal-server-cloudimg-amd64-custom-20210609-0.raw"), readonly: false, direct: false, iommu: false, num_queues: 1, queue_size: 128, vhost_user: false, vhost_socket: None, poll_queue: true, rate_limiter_config: None, id: Some("_disk0"), disable_io_uring: false, pci_segment: 0 }
cloud-hypervisor: 14.129591ms: <vmm> INFO:vmm/src/device_manager.rs:1983 -- Using asynchronous RAW disk file (io_uring)
cloud-hypervisor: 14.159853ms: <vmm> INFO:vmm/src/device_manager.rs:1901 -- Creating virtio-block device: DiskConfig { path: Some("/tmp/disk"), readonly: false, direct: false, iommu: false, num_queues: 1, queue_size: 128, vhost_user: false, vhost_socket: None, poll_queue: true, rate_limiter_config: None, id: Some("_disk1"), disable_io_uring: false, pci_segment: 0 }
cloud-hypervisor: 22.110281ms: <vmm> INFO:vmm/src/device_manager.rs:1983 -- Using asynchronous RAW disk file (io_uring)

After:

cloud-hypervisor: 4.880411ms: <vmm> INFO:vmm/src/device_manager.rs:1916 -- Creating virtio-block device: DiskConfig { path: Some("/home/rob/workloads/focal-server-cloudimg-amd64-custom-20210609-0.raw"), readonly: false, direct: false, iommu: false, num_queues: 1, queue_size: 128, vhost_user: false, vhost_socket: None, poll_queue: true, rate_limiter_config: None, id: Some("_disk0"), disable_io_uring: false, pci_segment: 0 }
cloud-hypervisor: 14.105123ms: <vmm> INFO:vmm/src/device_manager.rs:1998 -- Using asynchronous RAW disk file (io_uring)
cloud-hypervisor: 14.134837ms: <vmm> INFO:vmm/src/device_manager.rs:1916 -- Creating virtio-block device: DiskConfig { path: Some("/tmp/disk"), readonly: false, direct: false, iommu: false, num_queues: 1, queue_size: 128, vhost_user: false, vhost_socket: None, poll_queue: true, rate_limiter_config: None, id: Some("_disk1"), disable_io_uring: false, pci_segment: 0 }
cloud-hypervisor: 14.221869ms: <vmm> INFO:vmm/src/device_manager.rs:1998 -- Using asynchronous RAW disk file (io_uring)

Signed-off-by: Rob Bradford <robert.bradford@intel.com>
This commit is contained in:
Rob Bradford 2021-11-12 10:38:51 +00:00
parent 6a7a588268
commit 3480e69ff5
1 changed files with 17 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
vmm/src/device_manager.rs
View File

@ -906,6 +906,9 @@ pub struct DeviceManager {
// Helps identify if the VM is currently being restored
restoring: bool,
// io_uring availability if detected
io_uring_supported: Option<bool>,
}
impl DeviceManager {
@ -1043,6 +1046,7 @@ impl DeviceManager {
gpio_device: None,
force_iommu,
restoring,
io_uring_supported: None,
};
let device_manager = Arc::new(Mutex::new(device_manager));
@ -1886,6 +1890,17 @@ impl DeviceManager {
Ok(devices)
}
// Cache whether io_uring is supported to avoid probing for very block device
fn io_uring_is_supported(&mut self) -> bool {
if let Some(supported) = self.io_uring_supported {
return supported;
}
let supported = block_io_uring_is_supported();
self.io_uring_supported = Some(supported);
supported
}
fn make_virtio_block_device(
&mut self,
disk_cfg: &mut DiskConfig,
@ -1962,7 +1977,7 @@ impl DeviceManager {
ImageType::FixedVhd => {
// Use asynchronous backend relying on io_uring if the
// syscalls are supported.
if block_io_uring_is_supported() && !disk_cfg.disable_io_uring {
if self.io_uring_is_supported() && !disk_cfg.disable_io_uring {
info!("Using asynchronous fixed VHD disk file (io_uring)");
Box::new(
FixedVhdDiskAsync::new(file)
@ -1979,7 +1994,7 @@ impl DeviceManager {
ImageType::Raw => {
// Use asynchronous backend relying on io_uring if the
// syscalls are supported.
if block_io_uring_is_supported() && !disk_cfg.disable_io_uring {
if self.io_uring_is_supported() && !disk_cfg.disable_io_uring {
info!("Using asynchronous RAW disk file (io_uring)");
Box::new(RawFileDisk::new(file)) as Box<dyn DiskFile>
} else {