Add measurement for cilium BPF map pressure

This change allows conditional gathering of cilium_bpf_map_pressure in
CL2 load scenario.

Having this measurement allows to track one of the limitations which might be
faced while scaling DPv2 clusters to larger number of nodes and Network
Policies.

eBPF section with bpf_map_pressure metric in cilium docs: https://docs.cilium.io/en/stable/observability/metrics/#ebpf

Author: ILL1A

clusterloader2/testing/load/modules/measurements.yaml

@@ -30,6 +30,8 @@
 {{$ENABLE_CONTAINER_RESOURCES_MEASUREMENT := DefaultParam .CL2_ENABLE_CONTAINER_RESOURCES_MEASUREMENT false}}
 {{$ENABLE_TERMINATED_WATCHES_MEASUREMENT := DefaultParam .CL2_ENABLE_TERMINATED_WATCHES_MEASUREMENT false}}
 {{$ENABLE_QUOTAS_USAGE_MEASUREMENT := DefaultParam .CL2_ENABLE_QUOTAS_USAGE_MEASUREMENT false}}
+{{$ENABLE_BPF_MAP_PRESSURE_MEASUREMENT := DefaultParam .CL2_ENABLE_BPF_MAP_PRESSURE_MEASUREMENT false}}
+{{$BPF_MAP_PRESSURE_MAX_THRESHOLD := DefaultParam .CL2_BPF_MAP_PRESSURE_MAX_THRESHOLD 90}}
 {{$ALLOWED_CONTAINER_RESTARTS := DefaultParam .CL2_ALLOWED_CONTAINER_RESTARTS 1}}
 {{$CUSTOM_ALLOWED_CONTAINER_RESTARTS := DefaultParam .CL2_CUSTOM_ALLOWED_CONTAINER_RESTARTS ""}}
 {{$NODE_LOCAL_DNS_LATENCY_THRESHOLD := DefaultParam .CL2_NODE_LOCAL_DNS_LATENCY_THRESHOLD "5s"}}
@@ -229,6 +231,19 @@ steps:
       - name: max
         query: max_over_time(sum by (quota_metric) (irate(serviceruntime_googleapis_com:quota_rate_net_usage{monitored_resource="consumer_quota"}[1m]))[%v:]) * 60
 {{end}}
+{{if $ENABLE_BPF_MAP_PRESSURE_MEASUREMENT}}
+  - Identifier: BPFMapPressure
+    Method: GenericPrometheusQuery
+    Params:
+      action: {{$action}}
+      metricName: BPF Map Pressure
+      metricVersion: v1
+      unit: "%"
+      queries:
+      - name: BPF Map Pressure (Max)
+        query: max_over_time(max(cilium_bpf_map_pressure)[%v:]) * 100
+        threshold: {{$BPF_MAP_PRESSURE_MAX_THRESHOLD}}
+{{end}}
 {{if $ENABLE_CEP_PROPAGATION_DELAY_MEASUREMENT}}
   - Identifier: CiliumEndpointPropagationDelay
     Method: CiliumEndpointPropagationDelay