Extending machine API by number of physical cpu cores and cpu sockets

[katarzyna-z]

Signed-off-by: Katarzyna Kujawa katarzyna.kujawa@intel.com

Summary of changes:

• Extended metrics API by number of physical cpu cores (num_physical_cores) and cpu sockets (num_sockets), changes visible on /api/v2.0/machine in following form:

{
    "num_cores": 8,
    "num_physical_cores": 4,
    "num_sockets": 1,
    "cpu_frequency_khz": 4000000,
     ....
}

• Modified regular expression used for parsing /proc/cpuinfo to get information about core id and physical id to deal with multi line input string without iterating through lines
• Replaced const cpuBusPath with var cpuBusPath to easily modify sysfs cpu path in tests
• Added functions to count unique occurrences of CPU properties using regular expressions and reading from sysfs cpu path
• Extended unit tests to cover introduced changes

[k8s-ci-robot]

Hi @katarzyna-z. Thanks for your PR.

I'm waiting for a google member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

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[iwankgb]

This is related to #2388.

[dashpole]

/ok-to-test

[dashpole]

lgtm, nice work.