File source has suboptimial performance degredation as line sizes increase

[blt]

Vector Version

Custom build of 0327d46. Build string:

RUSTFLAGS="-g" cargo build --no-default-features --features "sources-file,sources-internal_metrics,sinks-prometheus,sinks-blackhole" --release 

Vector Configuration File

data_dir = "data"

[sources.internal]
type = "internal_metrics"

[sources.file]
type = "file"
max_line_bytes = 102400
fingerprint.strategy = "device_and_inode"
include = ["logs/*.log"]

[sinks.prometheus]
type = "prometheus_exporter"
inputs = ["internal"]
address = "0.0.0.0:9001"

[sinks.blackhole]
type = "blackhole"
inputs = ["file"]

Debug Output

Expected Behavior

The file source as of the above commit demonstrates a sub-optimal throughput drop-off when line sizes go beyond 100Kb. Before this point the source is capable of processing at least 25Mb/s -- see vectordotdev/vector-test-harness#74 for details -- but after this performance drops off significantly all the way to 900Kb/s.

Actual Behavior

vectordotdev/vector-test-harness#74 (comment)

This will cause vector to hold onto file descriptors, as a result. This fills up user disks, given enough time.

Example Data

See referenced issue.

Additional Context

See referenced issue.

References

• Initial new profiling work vector-test-harness#74