jgrusewski 379cc446e2 determinism: deterministic per-warp reduction in monitoring_reduce kernel
The monitoring kernel computed reward/action statistics for HEALTH_DIAG and
log output. Each of 8 warps used per-warp reduction via shfl, then the
warp's lane-0 atomicAdd-ed its partial into 14 shared scalars/arrays:

  atomicAdd(&s_sum, ...)        // per-trade reward sum
  atomicAdd(&s_sq_sum, ...)     // sum of squares
  atomicMinFloat(&s_min, ...)   // CAS-based atomic min
  atomicMaxFloat(&s_max, ...)
  atomicAdd(&s_nonzero, ...)
  atomicAdd(&s_exp[i], ...)     // per-action histogram
  atomicAdd(&s_ord[i], ...)
  atomicAdd(&s_urg[i], ...)

Atomic-into-shared is order-of-arrival → for floats, a few-ULP variance
across runs in mean/std/sharpe/min/max LOG values, even when the underlying
inputs were bit-identical.

Diagnostic non-determinism is still bad: it makes A/B comparisons of kernel
changes unreliable, and bisecting a numeric regression by training-log diff
becomes impossible.

Fix: standard "warp-id-keyed scratch + sequential reduction by tid 0":

  __shared__ float w_sum[32], w_sq_sum[32], ...      // one slot per warp
  __shared__ int   w_exp[32][9], ...                  // arrays too
  if ((tid & 31) == 0) w_sum[warp_id] = local_sum;   // one writer per slot
  __syncthreads();
  if (tid == 0) {
      for (w = 0; w < num_warps; w++) total += w_sum[w];   // fixed order
      ...
  }

Results are now bit-identical across runs given identical inputs. Shared
memory cost: ~2.6 KB (32 warps × ~80 bytes), well under the 48 KB limit.

Also deleted the now-unused atomicMinFloat / atomicMaxFloat helper
__device__ functions (top of the file). They were the only callers.

The 4 remaining call-site atomicAdds in the codebase (3 in
experience_kernels for atom_stats/penalty_out, 1 in dqn_utility for
sensitivity_out, 1 in trade_stats) are similar diagnostic-only paths.
Each follows the same cross-block hierarchical-atomicAdd pattern used in
the just-deleted ensemble_diversity_kernel; same fix would apply but
they're individual cleanup follow-ups.

Net behavior change: zero (training trajectory unaffected — diagnostic
output values are now stable across same-input runs).

Files touched:
  crates/ml/src/cuda_pipeline/monitoring_kernel.cu  (-26 / -33 +62)

Verified: SQLX_OFFLINE=true cargo check -p ml --lib --tests passes.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
2026-04-21 09:05:00 +02:00

Foxhunt

Production HFT trading system in Rust.

Architecture

The workspace contains 32 crates organized as follows:

Core Libraries (16)

Crate Purpose
trading_engine Order processing, FIX 4.4, IB TWS, SIMD, RDTSC timing
risk VaR, Kelly, circuit breakers, kill switches, compliance
risk-data Risk data types and shared structures
trading-data Trading data types
ml DQN Rainbow, PPO, TFT, Mamba2, ensemble inference
ml-data ML data types and feature definitions
data Market data ingestion and storage
backtesting Replay engine, strategy tester
adaptive-strategy Ensemble execution, microstructure analysis
common Shared types, resilience, error handling
storage S3 and local model storage
model_loader Model serialization and loading
market-data Market data feed handlers
database PostgreSQL access layer (SQLx)
config Configuration management
tli CLI commands and tooling

Services (8)

Service Purpose
backtesting_service gRPC backtesting service
broker_gateway_service FIX routing, broker connectivity
trading_service Core trading operations
ml_training_service Model training orchestration
data_acquisition_service Market data acquisition
trading_agent_service Autonomous trading agents
api_gateway gRPC API gateway with auth
web-gateway Axum REST + WebSocket gateway

Frontend

web-dashboard/ -- React 19 + TypeScript + Vite + TradingView charts.

Building

# Check compilation (no PostgreSQL required)
SQLX_OFFLINE=true cargo check --workspace

# Run tests for a specific crate
SQLX_OFFLINE=true cargo test -p <crate> --lib

# Clippy
SQLX_OFFLINE=true cargo clippy --workspace

ML Models

Four production model architectures on Candle v0.9.1 with CUDA:

  • DQN Rainbow -- Deep Q-Network with prioritized replay, dueling heads, noisy nets
  • PPO -- Proximal Policy Optimization with GAE and LSTM policies
  • TFT -- Temporal Fusion Transformer for multi-horizon forecasting
  • Mamba2 -- State space model for sequence prediction

Each model has a standalone trainer and a UnifiedTrainable adapter for the hyperopt pipeline.

Infrastructure

  • Git: Gitea at git.fxhnt.ai (Tailscale-only), Scaleway DEV1-S
  • Observability: OpenTelemetry OTLP (env OTEL_EXPORTER_OTLP_ENDPOINT)
  • Database: PostgreSQL with SQLx offline mode for CI

License

Proprietary. All rights reserved.

Description
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