[dpdk-dev] [PATCH v9 0/9] Policy Based Power Control for Guest

Ferruh Yigit ferruh.yigit at intel.com
Thu Oct 12 02:23:48 CEST 2017

On 10/11/2017 5:18 PM, David Hunt wrote:
> Policy Based Power Control for Guest
> This patchset adds the facility for a guest VM to send a policy down to the
> host that will allow the host to scale up/down cpu frequencies
> depending on the policy criteria independently of the DPDK app running in
> the guest.  This differs from the previous vm_power implementation where
> individual scale up/down requests were send from the guest to the host via
> virtio-serial.
> V9 patchset changes:
>   * Rebased on top of the tip of the master branch
>   * changed port_id from uint8 to uint16 due to changes elsewhere
> V8 patchset changes:
>   * Added Ack's and Reviewed-by's to individual patches in the set so as to
>     keep patchwork A/R/T flags properly in sync.
> V7 patchset changes:
>   * Changed return code of rte_pmd_i40e_query_vfid_by_mac() from an
>     int64_t to int
> V6 patchset changes:
>   * Fixed comments in header for rte_pmd_i40e_query_vfid_by_mac.
>   * changed rte_pmd_i40e_query_vfid_by_mac return code from uint to int
>     as it can return negative error codes.
>   * Removed bool enum from channel_commands.h, including stdbool.h instead.
>   * Added #define VM_MAX_NAME_SZ 32 to channel_commands.h
>   * Renamed a few variables to be more readable.
>   * Added returns in a few places if failed to get info on domain.
>   * Fixed power_manager_init to keep track of num_freqs for each core.
>   * In power_manager_scale_core_med(), changed a hardcoded '5' to instead
>     be calculated from the centre of the frequency list
>     (global_core_freq_info[core_num].num_freqs / 2)
> V5 patchset changes:
>   * Removed most of the #ifdef I40_PMD as it will be applicable to
>     other PMDs in the future.
>   * Changed the parameter of rte_pmd_i40e_query_vfid_by_mac from a uint64
>     to a const struct ether_addr *, rather than casting it later in the
>     function.
> V4 patchset changes:
>   * None, re-post to mailing list under the correct email thread.
> V3 patchset changes:
>   * Changed to using is_same_ether_addr() instead of looping through
>     the mac address bytes to compare them.
>   * Tweaked some comments and working in the i40e patch after review.
>   * Added a patch to the set to add new i40e function to map file, so
>     as to allow shared library builds. The power library API needs a cleanup
>     in next release, so will add API/ABI warning for this cleanup in a
>     separate patch.
> V2 patchset changes:
>   * Removed API's in ethdev layer.
>   * Now just a single new API in the i40e driver for mapping VF MAC to
>     VF index.
>   * Moved new function from rte_rxtx.c to rte_pmd_i40e.c
>   * Removed function for reading i40e register, moved to using the
>     standard stats API.
>   * Renamed i40e function to rte_pmd_i40e_query_vfid_by_mac
>   * Cleaned up policy generation code.
> It's a modification of the vm_power_manager app that runs in the host, and
> the guest_vm_power_app example app that runs in the guest. This allows the
> guest to send down a policy to the host via virtio-serial, which then allows
> the host to scale up/down based on the criteria in the policy, resulting in
> quicker scale up/down than individual requests coming from the guest.
> It also means that the DPDK application running in the guest does not need
> to be modified in any way, it is unaware that it's cores are being scaled
> up/down, reducing the effort in implementing a power-aware infrastructure.
> The usage model is as follows:
> 1. Set up the VF's and assign to the guest in the usual way.
> 2. run vm_power_manager on the host, creating a channel to the guest.
> 3. Start the guest_vm_power_mgr app on the guest, which establishes
>    a virtio-serial channel to the host.
> 4. Send down the profile for the guest using the "send_profile now" command.
>    There is an example profile hard-coded into guest_vm_power_mgr.
> 5. Stop the guest_vm_power_mgr and run your normal power-unaware application.
> 6. Send traffic into the VFs at varying traffic rates.
>    Observe the frequency change on the host (turbostat -i 1)
> The sequence of code changes are as follows:
> A new function has been aded to the i40e driver to allow mapping of
> a VF MAC to VF index.
> Next we make an addition to librte_power that adds an extra command to allow
> the passing of a policy structure from the guest to the host. This struct
> contains information like busy/quiet hour, packet throughput thresholds, etc.
> The next addition adds functionality to convert the virtual CPU (vcpU0 IDs to
> physical CPU (pcpu) IDs so that the host can scale up/down the cores used
> in the guest.
> The remaining patches are functionality to process the policy, and take action
> when the relevant trigger occurs to cause a frequency change.

Applied to dpdk/master, thanks.

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