pkg/agent: Use eBPF map batch operations

This patch adds support for using eBPF batch operations on maps which
should dramatically improve the performance of the parca-agent by
enabling it to batch lookup and delete keys/values in maps in a single
operation.

This replaces the use of iterators in favor of iteration in batches.

Fixes parca-dev#74

go.mod

@@ -30,4 +30,8 @@ require (
 	k8s.io/cri-api v0.23.1
 )
 
-replace github.com/prometheus/prometheus => github.com/prometheus/prometheus v1.8.2-0.20201130085533-a6e18916ab40
+replace (
+	// github.com/aquasecurity/libbpfgo => github.com/aquasecurity/libbpfgo v0.2.2-libbpf-0.5.0.0.20211215154851-b168808861fe
+	github.com/aquasecurity/libbpfgo => /home/deparker/Code/libbpfgo
+	github.com/prometheus/prometheus => github.com/prometheus/prometheus v1.8.2-0.20201130085533-a6e18916ab40
+)

go.sum

@@ -174,8 +174,6 @@ github.com/antihax/optional v1.0.0/go.mod h1:uupD/76wgC+ih3iEmQUL+0Ugr19nfwCT1kd
 github.com/apache/arrow/go/arrow v0.0.0-20191024131854-af6fa24be0db/go.mod h1:VTxUBvSJ3s3eHAg65PNgrsn5BtqCRPdmyXh6rAfdxN0=
 github.com/apache/thrift v0.12.0/go.mod h1:cp2SuWMxlEZw2r+iP2GNCdIi4C1qmUzdZFSVb+bacwQ=
 github.com/apache/thrift v0.13.0/go.mod h1:cp2SuWMxlEZw2r+iP2GNCdIi4C1qmUzdZFSVb+bacwQ=
-github.com/aquasecurity/libbpfgo v0.2.2-libbpf-0.5.0 h1:Qecy9Qvj4TG0LK7sfuJWzd1QlwMozHo7H0AyZMGjLg8=
-github.com/aquasecurity/libbpfgo v0.2.2-libbpf-0.5.0/go.mod h1:/+clceXE103FaXvVTIY2HAkQjxNtkra4DRWvZYr2SKw=
 github.com/armon/circbuf v0.0.0-20150827004946-bbbad097214e/go.mod h1:3U/XgcO3hCbHZ8TKRvWD2dDTCfh9M9ya+I9JpbB7O8o=
 github.com/armon/consul-api v0.0.0-20180202201655-eb2c6b5be1b6/go.mod h1:grANhF5doyWs3UAsr3K4I6qtAmlQcZDesFNEHPZAzj8=
 github.com/armon/go-metrics v0.0.0-20180917152333-f0300d1749da/go.mod h1:Q73ZrmVTwzkszR9V5SSuryQ31EELlFMUz1kKyl939pY=