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    "msgid": "<>",
    "date": "2018-06-26T09:23:08",
    "name": "[0/9] examples/vm_power: 100% Busy Polling",
    "submitter": {
        "id": 342,
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        "name": "David Hunt",
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            "date": "2018-06-26T09:23:08",
            "name": "examples/vm_power: 100% Busy Polling",
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        "From": "David Hunt <>",
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        "Sender": "\"dev\" <>",
        "Subject": "[dpdk-dev] [0/9] examples/vm_power: 100% Busy Polling",
        "Precedence": "list",
        "Date": "Tue, 26 Jun 2018 10:23:08 +0100",
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    "content": "This patch set adds the capability to do out-of-band power\nmonitoring on a system. It uses a thread to monitor the branch\ncounters in the targeted cores, and calculates the branch ratio\nif the running code.\n\nIf the branch ratop is low (0.01), then\nthe code is most likely running in a tight poll loop and doing\nnothing, i.e. receiving no packets. In this case we scale down\nthe frequency of that core.\n\nIf the branch ratio is higher (>0.01), then it is likely that\nthe code is receiving and processing packets. In this case, we\nscale up the frequency of that core.\n\nThe cpu counters are read via /dev/cpu/x/msr, so requires the\nmsr kernel module to be loaded. Because this method is used,\nthe patch set is implemented with one file for x86 systems, and\nanother for non-x86 systems, with conditional compilation in\nthe Makefile. The non-x86 functions are stubs, and do not\ncurrently implement any functionality.\n\nThe vm_power_manager app has been modified to take a new parameter\n   --core-list or -l\nwhich takes a list of cores in a comma-separated list format,\ne.g. 1,3,5-7,9, which resolvest to a core list of 1,3,5,6,7,9\nThese cores will then be enabled for oob monitoring. When the\nOOB monitoring thread starts, it reads the branch hits/miss\ncounters of each monitored core, and scales up/down accordingly.\n\nThe guest_cli app has also been modified to allow sending of a\npolicy of type BRANCH_RATIO where all of the cores included in\nthe policy will be monitored by the vm_power_manager oob thread.\n\nv2 changes:\n   * Add the guest_cli patch into this patch set, including the\n     ability to set the policy to BRANCH_RATIO.\n\n   * When vm_power_manger receives a policy with type BRANCH_RATIO,\n     add the relevant cores to the monitoring thread.\n\nv3 changes:\n   * Added a command line parameter to alloe changing of the\n     default branch ratio threshold. can now use -b 0.3 or\n     --branch-ratio=0.3 to set the ratio for scaling up/down.\n\n[1/9] examples/vm_power: add check for port count\n[2/9] examples/vm_power: add core list parameter\n[3/9] examples/vm_power: add oob monitoring functions\n[4/9] examples/vm_power: allow greater than 64 cores\n[5/9] examples/vm_power: add thread for oob core monitor\n[6/9] examples/vm_power: add port-list to command line\n[7/9] examples/vm_power: add branch ratio policy type\n[8/9] examples/vm_power: add cli args to guest app\n[9/9] examples/vm_power: make branch ratio configurable"