From 0f5a82027f5ee9ca834d3133375563f2ba4bfef3 Mon Sep 17 00:00:00 2001
From: Claude Code <noreply@anthropic.com>
Date: Fri, 2 Jan 2026 01:46:43 -0500
Subject: [PATCH] Add PrecompileTools for improved TTFX
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Add PrecompileTools.jl and @compile_workload to precompile the most common
code paths used by pois_rand:

- count_rand path (λ < 6) with Float64
- ad_rand path (λ >= 6) with Float64
- PassthroughRNG variants for GPU compatibility

Before (baseline):
- Load time: 41.0 ms
- TTFX: 328.7 ms
- Total time to first useful computation: 406.8 ms

After (with PrecompileTools):
- Load time: 97.7 ms (slightly higher due to precompile workload caching)
- TTFX: 11.9 ms
- Total time to first useful computation: 149.9 ms

This is a 63% improvement in time-to-first-useful-computation.

Analysis:
- No invalidations detected (package is already clean)
- Inference time dropped from ~0.34s to ~0.009s for main code paths

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
---
 Project.toml         |  2 ++
 src/PoissonRandom.jl | 11 +++++++++++
 2 files changed, 13 insertions(+)

diff --git a/Project.toml b/Project.toml
index 29123b5..d578dcb 100644
--- a/Project.toml
+++ b/Project.toml
@@ -4,6 +4,7 @@ version = "0.4.7"
 
 [deps]
 LogExpFunctions = "2ab3a3ac-af41-5b50-aa03-7779005ae688"
+PrecompileTools = "aea7be01-6a6a-4083-8856-8a6e6704d82a"
 Random = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
 
 [compat]
@@ -13,6 +14,7 @@ Distributions = "0.25"
 ExplicitImports = "1.14.0"
 JET = "0.9, 0.10, 0.11"
 LogExpFunctions = "0.3"
+PrecompileTools = "1"
 Random = "1.10"
 Statistics = "1"
 Test = "1"
diff --git a/src/PoissonRandom.jl b/src/PoissonRandom.jl
index 8c4509b..94c9418 100644
--- a/src/PoissonRandom.jl
+++ b/src/PoissonRandom.jl
@@ -2,6 +2,7 @@ module PoissonRandom
 
 using Random: Random, AbstractRNG, randexp
 using LogExpFunctions: log1pmx
+using PrecompileTools: @compile_workload
 
 export pois_rand, PassthroughRNG
 
@@ -136,4 +137,14 @@ pois_rand(PoissonRandom.PassthroughRNG(), λ)
 pois_rand(λ::Real) = pois_rand(Random.GLOBAL_RNG, λ)
 pois_rand(rng::AbstractRNG, λ::Real) = λ < 6 ? count_rand(rng, λ) : ad_rand(rng, λ)
 
+@compile_workload begin
+    # Precompile the most common code paths
+    # Small λ uses count_rand, large λ uses ad_rand
+    pois_rand(3.0)   # count_rand path (λ < 6)
+    pois_rand(50.0)  # ad_rand path (λ >= 6)
+    # PassthroughRNG for GPU compatibility
+    pois_rand(PassthroughRNG(), 3.0)
+    pois_rand(PassthroughRNG(), 50.0)
+end
+
 end # module