Hi Pablo and Alan, 2014-11-25 16:18, Pablo de Lara: > Virtual Machine Power Management. > > The following patches add two DPDK sample applications and an alternate > implementation of librte_power for use in virtualized environments. > The idea is to provide librte_power functionality from within a VM to address > the lack of MSRs to facilitate frequency changes from within a VM. > It is ideally suited for Haswell which provides per core frequency scaling. > > The current librte_power affects frequency changes via the acpi-cpufreq > 'userspace' power governor, accessed via sysfs. > > General Overview:(more information in each patch that follows). > The VM Power Management solution provides two components: > > 1)VM: Allows for the a DPDK application in a VM to reuse the librte_power > interface. Each lcore opens a Virto-Serial endpoint channel to the host, > where the re-implementation of librte_power simply forwards the requests for > frequency change to a host based monitor. The host monitor itself uses > librte_power. > Each lcore channel corresponds to a > serial device '/dev/virtio-ports/virtio.serial.port.poweragent.<lcore_num>' > which is opened in non-blocking mode. > While each Virtual CPU can be mapped to multiple physical CPUs it is > recommended that each vCPU should be mapped to a single core only. > > 2)Host: The host monitor is managed by a CLI, it allows for adding qemu/KVM > virtual machines and associated channels to the monitor, manually changing > CPU frequency, inspecting the state of VMs, vCPU to pCPU pinning and managing > channels. > Host channel endpoints are Virto-Serial endpoints configured as AF_UNIX file > sockets which follow a specific naming convention > i.e /tmp/powermonitor/<vm_name>.<channel_number>, > each channel has an 1:1 mapping to a VM endpoint > i.e. /dev/virtio-ports/virtio.serial.port.poweragent.<lcore_num> > Host channel endpoints are opened in non-blocking mode and are monitored via > epoll. > Requests over each channel to change frequency are forwarded to the original > librte_power. > > Channels must be manually configured as qemu-kvm command line arguments or > libvirt domain definition(xml) e.g. > <controller type='virtio-serial' index='0'> > <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/> > </controller> > <channel type='unix'> > <source mode='bind' path='/tmp/powermonitor/<vm_name>.<channel_num>'/> > <target type='virtio' name='virtio.serial.port.poweragent.<channel_num>/> > <address type='virtio-serial' controller='0' bus='0' port='<N>'/> > </channel> > > Where multiple channels can be configured by specifying multiple <channel> > elements, by replacing <vm_name>, <channel_num>. > <N>(port number) should be incremented by 1 for each new channel element. > More information on Virtio-Serial can be found here: > http://fedoraproject.org/wiki/Features/VirtioSerial > To enable the Hypervisor creation of channels, the host endpoint directory > must be created with qemu permissions: > mkdir /tmp/powermonitor > chown qemu:qemu /tmp/powermonitor > > The host application runs on two separate lcores: > Core N) CLI: For management of Virtual Machines adding channels to Monitor > thread, > inspecting state and manually setting CPU frequency [PATCH 02/09] > Core N+1) Monitor Thread: An epoll based infinite loop that waits on channel > events > from VMs and calls the corresponding librte_power functions. > > A sample application is also provided to run on Virtual Machines, this > application provides a CLI to manually set the frequency of a > vCPU[PATCH 08/09] > > The current l3fwd-power sample application can also be run on a VM. > > Changes in V6: > Fixed typos and missing some identations and blank lines > > Changes in V5: > Fixed default target in sample app Makefiles > > Changes in V4: > Fixed double free of channel during VM shutdown. > > Changes in V3: > Fixed crash in Guest CLI when host application is not running. > Renamed #defines to be more specific to the module they belong > Added vCPU pinning via CLI > > Changes in V2: > Runtime selection of librte_power implementations. > Updated Unit tests to cover librte_power changes. > PATCH[0/3] was sent twice, again as PATCH[0/4] > Miscellaneous fixes. > > Alan Carew (10): > Channel Manager and Monitor for VM Power Management(Host). > VM Power Management CLI(Host). > CPU Frequency Power Management(Host). > VM Power Management application and Makefile. > VM Power Management CLI(Guest). > VM communication channels for VM Power Management(Guest). > librte_power common interface for Guest and Host > Packet format for VM Power Management(Host and Guest). > Build system integration for VM Power Management(Guest and Host) > VM Power Management Unit Tests
Thanks to my shiny updated checkpatch, I was able to fix these 2 typos: WARNING:MISSING_SPACE: break quoted strings at a space character #831: FILE: examples/vm_power_manager/channel_manager.c:722: + RTE_LOG(ERR, CHANNEL_MANAGER, "Error connecting to %s, connection" + "already established\n", path); WARNING:MISSING_SPACE: break quoted strings at a space character #1424: FILE: examples/vm_power_manager/channel_monitor.c:181: + RTE_LOG(ERR, CHANNEL_MONITOR, "Unable to rte_malloc for" + "epoll events\n"); This codebase is really too big to be properly reviewed. As discussed earlier, it's a workaround for a missing feature in Qemu/KVM. It's now applied in DPDK but it would be really more convenient for everyone if it could be fixed upstream. I hope you'll be able to sustain this work for the goodness of every implied communities. Thank you -- Thomas
