1a1aad921b
accel-config is a utility library for controlling and configuring
Intel DSA (Data Streaming Accelerator Architecture) sub-system in the
Linux kernel.
accel-config-test utility has test cases that exercise the DSA subsysem.
It uses libaccel-config API to configure workqueues and issues ENQCMD
and MOVDIR64 instructions to move memory.
Intel DSA is a high-performance data copy and transformation accelerator
integrated into processors starting with 4th Generation Intel Xeon
processors. It is targeted for optimizing streaming data movement and
transformation operations common with applications for high-performance
storage, networking, persistent memory, and various data processing
applications.
Test Plan:
PASS: Build accel-config package.
PASS: Build local stx-debian base image
(from cgcs-root/build-tools/build-docker-images directory):
./build-stx-base.sh --local
PASS: Build stx-debian-tools-dev using the previous built image as base:
./build-stx-images.sh --base <your_user>/stx-debian:11.2
--no-pull-base --only stx-debian-tools-dev
PASS: Run stx-debian-tools-dev container and confirm that accel-config
utility is present and is executable with:
accel-config list
NOTE: Executing on stx kernel 5.10 returns that idxd module can
not be loaded. Running with stx kernel 6.6 gives the right output.
PASS: Replace accel-config-demo pod image from [1] to the recently built
stx-debian-tools-dev image. Create the pod and verify its logs:
kubectl logs dsa-accel-config-demo | tail
NOTE: You need stx intel-device-plugins app with
intel-device-plugins-dsa chart enabled [2]
[1] https://github.com/intel/intel-device-plugins-for-kubernetes/blob
/release-0.29/demo/dsa-accel-config-demo-pod.yaml
[2] https://opendev.org/starlingx/app-intel-device-plugins
Story: 2011040
Task: 49717
Change-Id: I87012212c210b0f63d6346faf1dcbd42b80efce6
Signed-off-by: Alyson Deives Pereira <alyson.deivespereira@windriver.com>
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|---|---|---|
| ceph | ||
| security | ||
| tools | ||
| utilities | ||
| .gitignore | ||
| .gitreview | ||
| .zuul.yaml | ||
| bindep.txt | ||
| centos_build_layer.cfg | ||
| centos_dev_docker_images.inc | ||
| centos_dev_wheels.inc | ||
| centos_guest_image_rt.inc | ||
| centos_guest_image.inc | ||
| centos_iso_image.inc | ||
| centos_pkg_dirs | ||
| centos_stable_docker_images.inc | ||
| centos_stable_wheels.inc | ||
| centos_tarball-dl.lst | ||
| CONTRIBUTING.rst | ||
| debian_build_layer.cfg | ||
| debian_iso_image.inc | ||
| debian_pkg_dirs | ||
| debian_stable_docker_images.inc | ||
| debian_stable_wheels.inc | ||
| HACKING.rst | ||
| pylint.rc | ||
| README.rst | ||
| requirements.txt | ||
| test-requirements.txt | ||
| tox.ini | ||
utilities
This file serves as documentation for the components and features included on the utilities repository.
PCI IRQ Affinity Agent
While in OpenStack it is possible to enable instances to use PCI devices, the interrupts generated by these devices may be handled by host CPUs that are unrelated to the instance, and this can lead to a performance that is lower than it could be if the device interrupts were handled by the instance CPUs.
The agent only acts over instances with dedicated vCPUs. For instances using shared vCPUs no action will be taken by the agent.
The expected outcome from the agent operation is achieving a higher performance by assigning the instances core to handle the interrupts from PCI devices used by these instances and avoid interrupts consuming excessive cycles from the platform cores.
Agent operation
The agent operates by listening to RabbitMQ notifications from Nova. When an instance is created or moved to the host, the agent checks for an specific flavor spec (detailed below) and if it does then it queries libvirt to map the instance vCPUs into pCPUs from the host.
Once the agent has the CPU mapping, it determines the IRQ for each PCI device used by the instance, and then it loops over all PCI devices and determines which host NUMA node is associated with the device, the pCPUs that are associated with the NUMA node and finally set the CPU affinity for the IRQs of the PCI device based on the pCPU list.
There is also a periodic audit that runs every minute and loops over the existing IRQs, so that if there are new IRQs that weren't mapped before the agent maps them, and if there are PCI devices that aren't associated to an instance that they were before, their IRQ affinity is reset to the default value.
Flavor spec
The PCI IRQ Affinity Agent uses a specific flavor spec for PCI interrupt affining, that is used to determine which vCPUs assigned to the instance must handle the interrupts from the PCI devices:
hw:pci_irq_affinity_mask=<vcpus_cpulist>
Where vcpus_cpulist can assume a comma-separated list of
values that can be expressed as:
int: the vCPU expressed byintwill be assigned to handle the interruptions from the PCI devicesint1-int2: the vCPUs betweenint1andint2(inclusive) will be used to handle the interruptions from the PCI devices^int: the vCPU expressed byintwill not be assigned to handle the interruptions from the PCI devices and shall be used to exclude a vCPU that was included in a previous range
NOTE: int must be a value between
0 and flavor.vcpus - 1
Example: hw_pci_irq_affinity_mask=1-4,^3,6 means that
vCPUs with indexes 1,2,4 and 6 from the vCPU list that Nova
allocates to the instance will be assigned to handle interruptions from
the PCI devices.
Limitations
- No CPU affining is performed for instances using shared CPUs (i.e.,
when using flavor spec
hw:cpu_policy=shared) - No CPU affining will be performed when invalid ranges are specified on the flavor spec, the agent instead will log error messages indicating the problem
Agent packaging
The agent code resides on the starlingx/utilities repo,
along with the spec and docker_image files that are used to build a
CentOS image with the agent wheel installed on it.
The agent is deployed by Armada along with the other OpenStack helm
charts; refer to PCI
IRQ Affinity Agent helm chart on
starlingx/openstack-armada-app repository.