)]}'
{
  "commit": "2852e5675f49de002e249ea0597d3900836fae94",
  "tree": "e49b8de2a1658ea9c24adc8015f3f58bcacdb295",
  "parents": [
    "fc86904b885a859830ea915bbb384e51c42cc091"
  ],
  "author": {
    "name": "Zimuzo Ezeozue",
    "email": "zezeozue@google.com",
    "time": "Wed Oct 14 11:48:03 2026 +0000"
  },
  "committer": {
    "name": "Zimuzo Ezeozue",
    "email": "zezeozue@google.com",
    "time": "Wed Oct 14 11:48:03 2026 +0000"
  },
  "message": "tp: speed up loading of perfetto exports\n\nLoading a perfetto export spent most of its time copying column data\nout of the archive and doing work at EOF which most sessions never use.\n\n- Alias numeric column buffers directly in the (mmap-backed) trace blob\n  instead of copying them: Arrow buffers are aligned, so when the\n  values are contiguous Slab::FromShared wraps them with copy-on-write\n  semantics in FlexVector. Pages are only faulted in when queried.\n- Coalesce adjacent slices of the same TraceBlob in\n  TraceBlobViewReader so tables spanning ReadTrace chunk boundaries\n  stay contiguous (and therefore zero-copy).\n- Compute trace bounds lazily via __intrinsic_trace_start/end instead\n  of rebuilding a _trace_bounds table, and use the first row of\n  ts-sorted tables rather than scanning them.\n- Build the static dataframe indexes on first use (thread-safely via\n  std::call_once) rather than sorting them all at EOF.\n- Skip DeobfuscationTracker work when there are no mapping packets.\n\nOn a 285 MB Android trace (532 MB export, 1M slices) export load goes\nfrom 540 ms to 270 ms (raw proto load: 6.2 s).\n",
  "tree_diff": [
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      "new_mode": 33188,
      "new_path": "src/trace_processor/core/dataframe/arrow_deserializer.cc"
    },
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}