The Virtual Machine Power Management solution shows an example of
how a DPDK application can indicate its processing requirements using VM local
-only information(vCPU/lcore) to a Host based Monitor which is responsible
+only information(vCPU/lcore, etc.) to a Host based Monitor which is responsible
for accepting requests for frequency changes for a vCPU, translating the vCPU
to a pCPU via libvirt and affecting the change in frequency.
to the librte_power ACPI cpufreq sysfs based library.
The Host Application relies on both qemu-kvm and libvirt to function.
+ This monitoring application is responsible for:
+
+ - Accepting requests from client applications: Client applications can
+ request frequency changes for a vCPU, translating
+ the vCPU to a pCPU via libvirt and affecting the change in frequency.
+
+ - Accepting policies from client applications: Client application can
+ send a policy to the host application. The
+ host application will then apply the rules of the policy independent
+ of the application. For example, the policy can contain time-of-day
+ information for busy/quiet periods, and the host application can scale
+ up/down the relevant cores when required. See the details of the guest
+ application below for more information on setting the policy values.
+
+ - Out-of-band monitoring of workloads via cores hardware event counters:
+ The host application can manage power for an application in a virtualised
+ OR non-virtualised environment by looking at the event counters of the
+ cores and taking action based on the branch hit/miss ratio. See the host
+ application '--core-list' command line parameter below.
+
#. librte_power for Virtual Machines
Using an alternate implementation for the librte_power API, requests for
Compiling
~~~~~~~~~
-Compiling the Application
--------------------------
-
-To compile the sample application see :doc:`compiling`.
+For information on compiling DPDK and the sample applications
+see :doc:`compiling`.
The application is located in the ``vm_power_manager`` sub-directory.
+To build just the ``vm_power_manager`` application:
+
+.. code-block:: console
+
+ export RTE_SDK=/path/to/rte_sdk
+ export RTE_TARGET=build
+ cd ${RTE_SDK}/examples/vm_power_manager/
+ make
+
Running
~~~~~~~
set_cpu_freq {core_num} up|down|min|max
+There are also some command line parameters for enabling the out-of-band
+monitoring of branch ratio on cores doing busy polling via PMDs.
+
+ .. code-block:: console
+
+ --core-list {list of cores}
+
+ When this parameter is used, the list of cores specified will monitor the ratio
+ between branch hits and branch misses. A tightly polling PMD thread will have a
+ very low branch ratio, so the core frequency will be scaled down to the minimim
+ allowed value. When packets are received, the code path will alter, causing the
+ branch ratio to increase. When the ratio goes above the ratio threshold, the
+ core frequency will be scaled up to the maximum allowed value.
+
+ .. code-block:: console
+
+ --branch-ratio {ratio}
+
+ The branch ratio is a floating point number that specifies the threshold at which
+ to scale up or down for the given workload. The default branch ratio is 0.01,
+ and will need to be adjusted for different workloads.
+
+
Compiling and Running the Guest Applications
--------------------------------------------
-For compiling and running l3fwd-power, see :doc:`l3_forward_power_man`.
+l3fwd-power is one sample application that can be used with vm_power_manager.
A guest CLI is also provided for validating the setup.
For both l3fwd-power and guest CLI, the channels for the VM must be monitored by the
-host application using the *add_channels* command on the host.
+host application using the *add_channels* command on the host. This typically uses
+the following commands in the host application:
+
+.. code-block:: console
+
+ vm_power> add_vm vmname
+ vm_power> add_channels vmname all
+ vm_power> set_channel_status vmname all enabled
+ vm_power> show_vm vmname
+
Compiling
~~~~~~~~~
-#. export RTE_SDK=/path/to/rte_sdk
-#. cd ${RTE_SDK}/examples/vm_power_manager/guest_cli
-#. make
+For information on compiling DPDK and the sample applications
+see :doc:`compiling`.
+
+For compiling and running l3fwd-power, see :doc:`l3_forward_power_man`.
+
+The application is located in the ``guest_cli`` sub-directory under ``vm_power_manager``.
+
+To build just the ``guest_vm_power_manager`` application:
+
+.. code-block:: console
+
+ export RTE_SDK=/path/to/rte_sdk
+ export RTE_TARGET=build
+ cd ${RTE_SDK}/examples/vm_power_manager/guest_cli/
+ make
Running
~~~~~~~
-The application does not have any specific command line options other than *EAL*:
+The standard *EAL* command line parameters are required:
.. code-block:: console
- ./build/vm_power_mgr [EAL options]
+ ./build/guest_vm_power_mgr [EAL options] -- [guest options]
-The application for example purposes uses a channel for each lcore enabled,
-for example to run on cores 0,1,2,3 on a system with 4 memory channels:
+The guest example uses a channel for each lcore enabled. For example,
+to run on cores 0,1,2,3:
.. code-block:: console
- ./build/guest_vm_power_mgr -l 0-3 -n 4
+ ./build/guest_vm_power_mgr -l 0-3
+
+Optionally, there is a list of command line parameter should the user wish to send a power
+policy down to the host application. These parameters are as follows:
+
+ .. code-block:: console
+
+ --vm-name {name of guest vm}
+
+ This parameter allows the user to change the Virtual Machine name passed down to the
+ host application via the power policy. The default is "ubuntu2"
+
+ .. code-block:: console
+
+ --vcpu-list {list vm cores}
+
+ A comma-separated list of cores in the VM that the user wants the host application to
+ monitor. The list of cores in any vm starts at zero, and these are mapped to the
+ physical cores by the host application once the policy is passed down.
+ Valid syntax includes individial cores '2,3,4', or a range of cores '2-4', or a
+ combination of both '1,3,5-7'
+
+ .. code-block:: console
+
+ --busy-hours {list of busy hours}
+
+ A comma-separated list of hours within which to set the core frequency to maximum.
+ Valid syntax includes individial hours '2,3,4', or a range of hours '2-4', or a
+ combination of both '1,3,5-7'. Valid hours are 0 to 23.
+
+ .. code-block:: console
+
+ --quiet-hours {list of quiet hours}
+
+ A comma-separated list of hours within which to set the core frequency to minimum.
+ Valid syntax includes individial hours '2,3,4', or a range of hours '2-4', or a
+ combination of both '1,3,5-7'. Valid hours are 0 to 23.
+
+ .. code-block:: console
+
+ --policy {policy type}
+
+ The type of policy. This can be one of the following values:
+ TRAFFIC - based on incoming traffic rates on the NIC.
+ TIME - busy/quiet hours policy.
+ BRANCH_RATIO - uses branch ratio counters to determine core busyness.
+ Not all parameters are needed for all policy types. For example, BRANCH_RATIO
+ only needs the vcpu-list parameter, not any of the hours.
After successful initialization the user is presented with VM Power Manager Guest CLI:
.. code-block:: console
set_cpu_freq {core_num} up|down|min|max
+
+To start the application and configure the power policy, and send it to the host:
+
+.. code-block:: console
+
+ ./build/guest_vm_power_mgr -l 0-3 -n 4 -- --vm-name=ubuntu --policy=BRANCH_RATIO --vcpu-list=2-4
+
+Once the VM Power Manager Guest CLI appears, issuing the 'send_policy now' command
+will send the policy to the host:
+
+.. code-block:: console
+
+ send_policy now
+
+Once the policy is sent to the host, the host application takes over the power monitoring
+of the specified cores in the policy.
+
git.droids-corp.org / dpdk.git / commitdiff