Benchmark: Gitaly with Raft and Transactions

Objective

Benchmark Gitaly with Raft + Transactions enabled.

Scope

• Baseline: Gitaly
• Variant: Gitaly with Raft + Transactions enabled
• Workloads: The current mix of RPCs defined in master's k6-benchmark.js is a minimum workload that needs to be run. If additional workloads with different RPCs need to be run, start another report.
• EXT4 FS

Configuration:

 config:
      # Whether transactions should be enabled.
      transactions: true
      raft: true

Test Matrix

Suggestions:

• Concurrency:
  • Repos: 1...5
  • Parallel RPCs per repo: 1, 8, 32
• Repository shapes:
  • Small repos (many loose objects/files)
  • Medium repos (Decent number of commits, trees, branches)
  • Large monorepos (large packfiles, deep history)
• Raft Enabled/Disabled
• Transactions Enabled
• Cache state:
  • Cold-cache (drop_caches) vs steady-state warm cache

Documentation Requirements

• Follow standardized template

Deliverables

• Reproducible benchmark runs using the framework from #6732
• Comparison tables/plots: baseline vs Transactions (per workload and concurrency level)
• Analysis summarizing:
  • bottlenecks
  • snapshot latencies and impact of files and directories on snapshot performance
  • p95 latency per RPC
• Artifact bundle per run: raw results (JSON/CSV), system profile, flamegraphs
• Summary published to the this issue with links to artifacts