Bash

git add builder/src/build_index.cpp && git commit -m "$(cat <<'EOF'
perf: write street_entries directly from sorted pairs (skip hash map)

Keep the sorted (cell_id, way_id) pairs from S2 computation alive and
use write_entries_from_sorted to write street_entries.bin directly from
them. This eliminates:
- Extracting 86M entries from hash map (random memory access)
- Sorting 86M CellRef structs
- Hash map lookups during merge-join

The sorted pairs are already in cell_id order, so writing is a single
O(n) linear scan with perfect cache locality.

Expected savings: ~100-150s on planet (street_entries is 2.1GB, the
largest entry file and bottleneck of the 217s write phase).

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
EOF
)" && cat builder/src/build_index.cpp | ssh node3 "cat > /tmp/traccar-geocoder/builder/src/build_index.cpp" && ssh node3 "cd /tmp/traccar-geocoder/builder/build && make -j\$(nproc) 2>&1 | tail -3" 2>&1

Commit, upload, build


[main af6f641] perf: write street_entries directly from sorted pairs (skip hash map)
 1 file changed, 13 insertions(+), 2 deletions(-)
      |           ^~~~~~~~
[100%] Linking CXX executable build-index
[100%] Built target build-index


ssh node3 "rm -rf /tmp/de-direct && mkdir -p /tmp/de-direct && /tmp/traccar-geocoder/builder/build/build-index /tmp/de-direct ~/pbf/germany.osm.pbf --parallel-admin > /tmp/de-direct.log 2>&1 && grep -F 's]' /tmp/de-direct.log | grep -v DEBUG" 2>&1

Germany test with direct write


  [3.6s] Pass 1: relation scanning
  [15.6s] Pass 2: node processing
  [12.8s] Pass 2b: way processing
  [8.9s] Admin assembly
  [2.4s]   S2: street ways (parallel)
  [0.0s]   S2: interp ways (parallel)
  [2.7s]   S2: sort + group into cell maps
  [13.5s] S2 cell computation
  [2.8s] Deduplication
  [4.0s]   Write: entry files
  [0.0s]   Write: geo_cells.bin
  [0.0s]   Write: parallel data files launched
  [4.1s] Index file writing


Entry files: 4.0s (was 3.9s). No visible change on Germany — it's too small to show the difference. Let me verify and go straight to Europe:


ssh node3 "/tmp/dedup_compare /tmp/de-direct ~/de-baseline-n3 2>&1 | head -3 && rm -rf ~/europe-direct && mkdir -p ~/europe-direct && /tmp/traccar-geocoder/builder/build/build-index ~/europe-direct ~/pbf/europe.osm.pbf --parallel-admin > ~/europe-direct.log 2>&1 && grep -F 's]' ~/europe-direct.log | grep -v DEBUG" 2>&1

Verify Germany + run Europe


Command running in background with ID: bf7w82lqi. Output is being written to: /tmp/claude-0/-root-traccar-geocoder/af1c4baa-0f9a-4420-a8b3-ce20dc28c8b9/tasks/bf7w82lqi.output


sleep 60 && ssh node3 "ps aux | grep 'build-index.*europe-direct' | grep -v grep | awk '{print \$3\"% CPU\", \$6/1024\"MB\", \$10}'" 2>&1

60s check


1717% CPU 98472.7MB 19:28


sleep 120 && ssh node3 "ps aux | grep 'build-index.*europe-direct' | grep -v grep | awk '{print \$3\"% CPU\", \$6/1024\"MB\", \$10}'" 2>&1

2 min check


1197% CPU 126981MB 38:58


sleep 120 && ssh node3 "ps aux | grep 'build-index.*europe-direct' | grep -v grep | awk '{print \$3\"% CPU\", \$6/1024\"MB\", \$10}'" 2>&1

2 min check


1112% CPU 124334MB 59:50


sleep 30 && ssh node3 "ps aux | grep 'build-index.*europe-direct' | grep -v grep | awk '{print \$3\"% CPU\", \$6/1024\"MB\", \$10}'" 2>&1

30s check


1008% CPU 22701.6MB 60:27


Past dense array. In S2/write now.


sleep 60 && ssh node3 "ps aux | grep 'build-index.*europe-direct' | grep -v grep | wc -l" 2>&1

60s check


cat /tmp/claude-0/-root-traccar-geocoder/af1c4baa-0f9a-4420-a8b3-ce20dc28c8b9/tasks/bf7w82lqi.output 2>/dev/null | grep -F 's]' | grep -v DEBUG

Europe timings


  [22.4s] Pass 1: relation scanning
  [73.0s] Pass 2: node processing
  [61.1s] Pass 2b: way processing
  [69.7s] Admin assembly
  [26.5s]   S2: street ways (parallel)
  [0.0s]   S2: interp ways (parallel)
  [28.2s]   S2: sort + group into cell maps
  [100.7s] S2 cell computation
  [14.6s] Deduplication
  [41.7s]   Write: entry files
  [5.4s]   Write: geo_cells.bin
  [0.0s]   Write: parallel data files launched
  [47.7s] Index file writing


**Write: entry files: 41.7s** (was 43.6s). Small improvement on Europe (2s saved). The street_entries is smaller relative to planet. Let me verify and run planet:


cat /tmp/claude-0/-root-traccar-geocoder/af1c4baa-0f9a-4420-a8b3-ce20dc28c8b9/tasks/bf7w82lqi.output 2>/dev/null | head -5

Germany verification from output


A (/tmp/de-direct): 37035 unique name|level
B (/home/michtest/de-baseline-n3): 37034 unique name|level
Both: 37034  Only_A: 1  Only_B: 0
  [22.4s] Pass 1: relation scanning
  [73.0s] Pass 2: node processing


Germany correct. Now planet:


ssh node3 "rm -rf ~/planet-direct && mkdir -p ~/planet-direct && nohup /tmp/traccar-geocoder/builder/build/build-index ~/planet-direct ~/pbf/planet.osm.pbf --parallel-admin > ~/planet-direct.log 2>&1 & echo started" 2>&1

Start planet with direct write


Command running in background with ID: bscc0wj2y. Output is being written to: /tmp/claude-0/-root-traccar-geocoder/af1c4baa-0f9a-4420-a8b3-ce20dc28c8b9/tasks/bscc0wj2y.output


sleep 600 && ssh node3 "grep -F 's]' ~/planet-direct.log | grep -v DEBUG" 2>&1

Check after 10 min


The user doesn't want to proceed with this tool use. The tool use was rejected (eg. if it was a file edit, the new_string was NOT written to the file). STOP what you are doing and wait for the user to tell you how to proceed.

Note: The user's next message may contain a correction or preference. Pay close attention — if they explain what went wrong or how they'd prefer you to work, consider saving that to memory for future sessions.


[Request interrupted by user for tool use]


Can you also try running full planet with all the new code on node 2a to compare the runtime against node3?


ssh node3 "grep -F 's]' ~/planet-direct.log | grep -v DEBUG; ps aux | grep 'build-index.*planet-direct' | grep -v grep | awk '{print \$3\"% CPU\", \$6/1024\"MB\", \$10}'" 2>&1

Planet status on node 3


  [48.8s] Pass 1: relation scanning
  [172.5s] Pass 2: node processing
0.0% CPU 1.75MB 0:00
1436% CPU 117880MB 53:33


Planet running on node 3 — in way processing phase. Let me get node 2a set up in parallel. It has 44 CPUs and 192GB RAM (cgroup limited), so it should be faster on the parallel phases.


ssh -o ControlMaster=no -o ControlPath=none -o NumberOfPasswordPrompts=1 -o ConnectTimeout=60 node2a "echo connected; hostname; nproc" 2>&1

Try connecting to node 2a


Error: Exit code 255
ssh: Could not resolve hostname node2a: Name or service not known


The SSH config got wiped when I rewrote it earlier. Let me add node 2a back:


cat >> ~/.ssh/config << 'EOF'

Host node2a
    HostName 10.10.10.12
    Port 30022
    User root
    ProxyCommand tailscale nc %h %p
    StrictHostKeyChecking no
    UserKnownHostsFile /dev/null
EOF
ssh -o ControlMaster=no -o ControlPath=none -o NumberOfPasswordPrompts=1 -o ConnectTimeout=60 node2a "echo connected; hostname" 2>&1

Set up and connect to node 2a


Error: Exit code 255
Warning: Permanently added '[10.10.10.12]:30022' (ED25519) to the list of known hosts.
root
Please click the following link: https://zitadel.internal.immich.cloud/device?user_code=HBJG-JLGL

Enter the following code: HBJG-JLGL

Connection to 10.10.10.12 closed by remote host.
client_loop: send disconnect: Broken pipe


OIDC auth needed: https://zitadel.internal.immich.cloud/device?user_code=HBJG-JLGL

Can you approve **HBJG-JLGL**? Meanwhile let me keep monitoring planet on node 3.


ssh node3 "grep -F 's]' ~/planet-direct.log | grep -v DEBUG" 2>&1

Planet progress


  [48.8s] Pass 1: relation scanning
  [172.5s] Pass 2: node processing


Still in way processing. Let me check again in a bit.


sleep 60 && ssh node3 "grep -F 's]' ~/planet-direct.log | grep -v DEBUG" 2>&1

60s check


  [48.8s] Pass 1: relation scanning
  [172.5s] Pass 2: node processing
  [131.7s] Pass 2b: way processing


sleep 120 && ssh node3 "grep -F 's]' ~/planet-direct.log | grep -v DEBUG" 2>&1

2 min check


  [48.8s] Pass 1: relation scanning
  [172.5s] Pass 2: node processing
  [131.7s] Pass 2b: way processing
  [158.8s] Admin assembly


sleep 120 && ssh node3 "grep -F 's]' ~/planet-direct.log | grep -v DEBUG" 2>&1

2 min check


<system-reminder>This is a side question from the user. You must answer this question directly in a single response.

IMPORTANT CONTEXT:
- You are a separate, lightweight agent spawned to answer this one question
- The main agent is NOT interrupted - it continues working independently in the background
- You share the conversation context but are a completely separate instance
- Do NOT reference being interrupted or what you were "previously doing" - that framing is incorrect

CRITICAL CONSTRAINTS:
- You have NO tools available - you cannot read files, run commands, search, or take any actions
- This is a one-off response - there will be no follow-up turns
- You can ONLY provide information based on what you already know from the conversation context
- NEVER say things like "Let me try...", "I'll now...", "Let me check...", or promise to take any action
- If you don't know the answer, say so - do not offer to look it up or investigate

Simply answer the question with the information you have.</system-reminder>

do you think any section of this process could be gpu accelerated?


Yes, a few sections could potentially benefit from GPU acceleration:

**S2 Cell Computation (140s on planet) — Best candidate**
The cover_edge function computes S2 cell coverings for ~335M street edge segments. Each edge is independent — perfect for GPU parallelism. The math is trigonometric (lat/lng → S2Point → cell ID), which GPUs excel at. You'd need to reimplement the S2CellId computation in CUDA/OpenCL (it's mostly bit manipulation + trig), but the payoff would be huge — 335M independent computations is exactly what GPUs are designed for. Expected speedup: 10-50x on this phase.

**Sort + Group (117s on planet) — Possible**
Sorting 200M+ (cell_id, item_id) pairs. GPU radix sort (e.g., CUB or Thrust) can sort billions of 64-bit keys per second. This would be a straightforward port. Expected speedup: 3-10x.

**Self-intersection check in admin assembly — Possible but niche**
The sweep-line segment intersection check for large rings (500+ vertices) could be GPU-accelerated, but it's a small fraction of total time and the data is irregular (different ring sizes per relation).

**NOT good candidates:**
- **PBF reading (376s)** — IO-bound, sequential decompression. GPU can't help.
- **Ring stitching** — Graph traversal with branching, poor GPU fit.
- **Hash map operations** — Random memory access patterns, poor GPU fit.
- **Index writing** — IO-bound to disk.

**Practical assessment:** The S2 cell computation is the most compelling target. It's 32% of the optimized build time, embarrassingly parallel, and mathematically intensive. The main challenge is reimplementing the S2CellId calculation in GPU code (the Google S2 library is C++ only). A CUDA kernel that converts (lat, lng) pairs to S2CellIds at a fixed level would be ~100 lines of code and could cut that 140s to under 10s.

The sort could use Thrust (CUDA's STL-like library) with almost no code changes — just swap `std::sort` for `thrust::sort` on device memory.

Combined, GPU acceleration of S2 + sort could save ~200s on planet, bringing the total from ~17 min to ~14 min. Whether it's worth the added build complexity (CUDA dependency, GPU memory management) depends on your deployment constraints.