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Feifei Cai ffcai

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ffcai / report.md
Created October 20, 2025 20:05
nanochat training report

nanochat training report

Generated: 2025-10-15 02:58:47

Environment

Git Information

  • Branch: master
  • Commit: 67aaca9 (dirty)
  • Message: export NANOCHAT_BASE_DIR so child processes get it too

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns
L2 cache reference ........................... 7 ns
Mutex lock/unlock ........................... 25 ns
Main memory reference ...................... 100 ns             
Compress 1K bytes with Zippy ............. 3,000 ns  =   3 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs