clj-ebpf.perf — org.clojars.pgdad/clj-ebpf 0.1.1

Perf event buffer support for BPF event streaming

create-perf-consumer clj

(create-perf-consumer
  &
  {:keys [map callback deserializer buffer-pages cpu-count]
   :or {deserializer identity buffer-pages 64 cpu-count (utils/get-cpu-count)}})

Create a perf event consumer for BPF event streaming.

Parameters:

• map: Perf event array map
• callback: Function to call for each event (receives deserialized event)
• deserializer: Function to deserialize event bytes (default identity)
• buffer-pages: Number of pages per buffer (default 64, must be power of 2)
• cpu-count: Number of CPUs (default: all CPUs)

Returns PerfEventConsumer record.

Example: (create-perf-consumer {:map perf-map :callback (fn [event] (println "Event:" event)) :deserializer parse-my-event :buffer-pages 64})

create-perf-event-array clj

(create-perf-event-array max-entries
                         &
                         {:keys [map-name] :or {map-name "perf_event_array"}})

Create a perf event array map for collecting BPF events.

A perf event array map is used to send events from BPF programs to userspace via perf event buffers.

Parameters:

• max-entries: Maximum number of entries (typically number of CPUs)
• map-name: Optional map name

Returns a BPF map.

Example: (create-perf-event-array (get-cpu-count) :map-name "events")

get-perf-stats clj

(get-perf-stats consumer)

Get statistics from perf event consumer.

Returns a map with:

• :events-read - Total events read from buffers
• :events-processed - Total events successfully processed
• :polls - Number of polling cycles
• :errors - Number of errors
• :uptime-ms - Consumer uptime in milliseconds
• :events-per-second - Average events processed per second

Example: (get-perf-stats consumer)

page-size clj

perf-event-flags clj

perf-event-open clj

(perf-event-open attr pid cpu group-fd flags)

Open a perf event file descriptor.

Parameters:

• attr: Perf event attribute map (see perf-event-attr->bytes)
• pid: Process ID (-1 for all processes)
• cpu: CPU number (-1 for all CPUs)
• group-fd: Group leader FD (-1 for no group)
• flags: Additional flags (default 0)

Returns the perf event file descriptor.

Example: (perf-event-open {:type :software :config :bpf-output} -1 0 -1 0)

perf-record-type clj

PERF_EVENT_OPEN_SYSCALL_NR clj

read-perf-events clj

(read-perf-events perf-buf)

(read-perf-events perf-buf max-events)

Read available events from perf buffer.

Returns a vector of event maps, each containing:

• :type - Event record type
• :size - Record size
• :data - Raw event data (byte array)

Parameters:

• perf-buf: PerfBuffer record
• max-events: Maximum number of events to read (default 128)

Example: (read-perf-events perf-buf 64)

start-perf-consumer clj

(start-perf-consumer consumer)

(start-perf-consumer consumer poll-interval-ms)

Start consuming events from perf buffers in a background thread.

Parameters:

• consumer: PerfEventConsumer record
• poll-interval-ms: Polling interval in milliseconds (default 100)

Returns updated consumer with thread reference.

Example: (start-perf-consumer consumer 50)

stop-perf-consumer clj

(stop-perf-consumer consumer)

Stop the perf event consumer thread.

Parameters:

• consumer: PerfEventConsumer record

Example: (stop-perf-consumer consumer)

with-perf-consumer clj macro

(with-perf-consumer [binding config-expr] & body)

Create and manage a perf event consumer with automatic cleanup.

Example: (with-perf-consumer [consumer {:map perf-map :callback println}] (start-perf-consumer consumer) (Thread/sleep 5000))