alice.mosphere.at / perlsky
perlsky is a Perl 5 implementation of an AT Protocol Personal Data Server.
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perlsky / docs / PERFORMANCE.md
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Performance#

This document covers two practical tools for perlsky performance work:

  • Prometheus metrics for live visibility
  • script/benchmark-local-appview for repeatable local endpoint timing

Benchmark Script#

script/benchmark-local-appview spins up an ephemeral local perlsky daemon, seeds a small repo with posts and a reply chain, then benchmarks the hottest local appview endpoints over real HTTP:

  • app.bsky.actor.getProfile
  • app.bsky.feed.getAuthorFeed
  • app.bsky.feed.getPostThread

Example:

script/benchmark-local-appview --iterations 75 --warmup 15 --posts 100 --replies 12

JSON output:

script/benchmark-local-appview --format json > data/local-appview-benchmark.json

The benchmark is intentionally small and deterministic. It is best for comparing one local appview change against another, not for claiming cluster-scale throughput.

Useful flags:

  • --iterations N: measured requests per endpoint, default 50
  • --warmup N: unmeasured warmup requests per endpoint, default 10
  • --posts N: number of posts to seed for the author feed, default 50
  • --replies N: length of the reply chain for the thread benchmark, default 8
  • --feed-limit N: getAuthorFeed page size, default 25
  • --keep-tmp: keep the temporary benchmark dataset on disk for inspection

The script also prints a metrics excerpt so it is easy to sanity-check whether local appview cache counters moved during the run.

For repeatable tuning:

  1. Run the benchmark script before a perf change and save the output.
  2. Apply the change.
  3. Run the same benchmark again with the same arguments.
  4. Compare:
    • p50
    • p95
    • max
    • derived req/s
  5. Check /metrics to confirm that cache hit/rebuild counters changed the way you expected.
  6. If the change looks promising, compare the same Prometheus panels in Grafana after deployment.

Current Hot Metrics#

The most relevant local appview metrics are:

  • perlsky_service_proxy_requests_total
  • perlsky_service_proxy_request_duration_seconds
  • perlsky_service_proxy_local_post_index_cache_access_total
  • perlsky_service_proxy_local_post_index_rebuild_duration_seconds
  • perlsky_service_proxy_local_post_index_entries
  • perlsky_service_proxy_local_post_resolution_total
  • perlsky_service_proxy_profile_record_cache_total
  • perlsky_repo_resolution_total

See METRICS.md for Prometheus and Grafana queries.