Trying to monitor the CPU ready time (hypervisor.cpu_ready_time_ppm)

API v1 has stats as part of the VMs

[…]
  "entities": [
    {
      "vmId": “xxxxxxxxxxxxxx”,
      "uuid": “xxxxxxx”,
      "powerState": "off",
      "vmName": “abcd”,
      "guestOperatingSystem": null,
      "ipAddresses": [],
      "hypervisorType": "kKvm",
      "hostName": null,
      "hostId": null,
      "hostUuid": null,
      "containerIds": [
        “xxxxxx8"
      […]
      "stats": {
        "hypervisor_avg_io_latency_usecs": "-1",
        "num_read_iops": "-1",
        "hypervisor_write_io_bandwidth_kBps": "-1",
        "timespan_usecs": "-1",
        "controller_num_read_iops": "-1",
        "controller.storage_tier.ssd.usage_bytes": "97837056",
        "read_io_ppm": "-1",
        "controller_num_iops": "-1",
        "hypervisor_memory_assigned_bytes": "-1",
        "total_read_io_time_usecs": "-1",
        "controller_total_read_io_time_usecs": "0",
        "controller.storage_tier.ssd.configured_pinned_bytes": "0",
        "hypervisor_num_io": "-1",
        "controller_total_transformed_usage_bytes": "0",
        "hypervisor_cpu_usage_ppm": "0",
        "controller_num_write_io": "-1",
        "avg_read_io_latency_usecs": "-1",
        "guest.memory_swapped_in_bytes": "-1",
        "controller_total_io_time_usecs": "0",
        "memory_usage_ppm": "0",
        "controller_total_read_io_size_kbytes": "0",
        "controller_num_seq_io": "-1",
        "controller_read_io_ppm": "-1",
        "controller_total_io_size_kbytes": "0",
        "hypervisor.cpu_ready_time_ppm": "-1",
        "controller_num_io": "0",
        "hypervisor_avg_read_io_latency_usecs": "-1",
        "num_write_iops": "-1",
        "controller_num_random_io": "0",
        "num_iops": "-1",
        "guest.memory_usage_ppm": "0",
        "hypervisor_num_read_io": "-1",
        "hypervisor_total_read_io_time_usecs": "-1",
        "controller_avg_io_latency_usecs": "-1",
        "num_io": "-1",
        "controller_num_read_io": "0",
        "hypervisor_num_write_io": "-1",
        "controller_seq_io_ppm": "-1",
        "guest.memory_usage_bytes": "0",
        "controller_read_io_bandwidth_kBps": "-1",
        "controller_io_bandwidth_kBps": "-1",
        "hypervisor_num_received_bytes": "0",
        "hypervisor_timespan_usecs": "-1",
        "hypervisor_num_write_iops": "-1",
        "total_read_io_size_kbytes": "-1",
        "hypervisor_total_io_size_kbytes": "-1",
        "avg_io_latency_usecs": "-1",
        "hypervisor_num_read_iops": "-1",
        "hypervisor_swap_in_rate_kBps": "-1",
        "controller_write_io_bandwidth_kBps": "-1",
        "controller_write_io_ppm": "-1",
        "controller_user_bytes": "9475319296",
        "hypervisor_avg_write_io_latency_usecs": "-1",
        "hypervisor_num_transmitted_bytes": "0",
        "hypervisor_total_read_io_size_kbytes": "-1",
        "read_io_bandwidth_kBps": "-1",
        "guest.memory_swapped_out_bytes": "-1",
        "hypervisor_memory_usage_ppm": "0",
        "hypervisor_num_iops": "-1",
        "hypervisor_io_bandwidth_kBps": "-1",
        "controller_num_write_iops": "-1",
        "total_io_time_usecs": "-1",
        "controller_random_io_ppm": "-1",
        "controller.storage_tier.das-sata.usage_bytes": "13925916672",
        "controller_avg_read_io_size_kbytes": "-1",
        "hypervisor_swap_out_rate_kBps": "-1",
        "total_transformed_usage_bytes": "-1",
        "avg_write_io_latency_usecs": "-1",
        "num_read_io": "-1",
        "write_io_bandwidth_kBps": "-1",
        "hypervisor_read_io_bandwidth_kBps": "-1",
        "hypervisor_consumed_memory_bytes": "0",
        "random_io_ppm": "-1",
        "total_untransformed_usage_bytes": "-1",
        "hypervisor_total_io_time_usecs": "-1",
        "num_random_io": "-1",
        "controller_avg_write_io_size_kbytes": "-1",
        "controller_avg_read_io_latency_usecs": "-1",
        "controller.storage_tier.das-sata.configured_pinned_bytes": "0",
        "num_write_io": "-1",
        "total_io_size_kbytes": "-1",
        "controller.storage_tier.cloud.usage_bytes": "0",
        "io_bandwidth_kBps": "-1",
        "controller_timespan_usecs": "0",
        "num_seq_io": "-1",
        "seq_io_ppm": "-1",
        "write_io_ppm": "-1",
        "controller_avg_write_io_latency_usecs": "-1"
      },

An article with examples Getting VM Performance Metrics via API as well.