From e16b2106e4549c133ecda8752cfe8b2a7ddbbb0a Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Ma=C5=82gorzata=20Zagajewska?= <m.zagajewska@gmail.com>
Date: Mon, 28 Sep 2026 19:30:54 +0200
Subject: [PATCH] Initialize the ggml timer when building sampler chains so
 they work without a backend on Windows

---
 Cargo.lock                                    |  1 +
 llama-cpp-bindings/Cargo.toml                 |  1 +
 llama-cpp-bindings/src/sampling.rs            |  2 ++
 .../tests/sampler_chain_without_backend.rs    | 24 +++++++++++++++++++
 4 files changed, 28 insertions(+)
 create mode 100644 llama-cpp-bindings/tests/sampler_chain_without_backend.rs

diff --git a/Cargo.lock b/Cargo.lock
index 01a64b40..33eeeca7 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -1165,6 +1165,7 @@ checksum = "11d3d7f243d5c5a8b9bb5d6dd2b1602c0cb0b9db1621bafc7ed66e35ff9fe092"
 name = "llama-cpp-bindings"
 version = "0.15.0"
 dependencies = [
+ "anyhow",
  "encoding_rs",
  "enumflags2",
  "llama-cpp-bindings-sys",
diff --git a/llama-cpp-bindings/Cargo.toml b/llama-cpp-bindings/Cargo.toml
index 0d49b00c..a00b03f5 100644
--- a/llama-cpp-bindings/Cargo.toml
+++ b/llama-cpp-bindings/Cargo.toml
@@ -24,6 +24,7 @@ thiserror = { workspace = true }
 toktrie = { workspace = true }
 
 [dev-dependencies]
+anyhow = { workspace = true }
 llama-cpp-wrapper-error-fixture = { workspace = true }
 serial_test = { workspace = true }
 
diff --git a/llama-cpp-bindings/src/sampling.rs b/llama-cpp-bindings/src/sampling.rs
index d8758173..cd9d3188 100644
--- a/llama-cpp-bindings/src/sampling.rs
+++ b/llama-cpp-bindings/src/sampling.rs
@@ -364,6 +364,8 @@ impl LlamaSampler {
         no_perf: bool,
     ) -> Result<Self, SamplingError> {
         unsafe {
+            llama_cpp_bindings_sys::ggml_time_init();
+
             let chain = llama_cpp_bindings_sys::llama_sampler_chain_init(
                 llama_cpp_bindings_sys::llama_sampler_chain_params { no_perf },
             );
diff --git a/llama-cpp-bindings/tests/sampler_chain_without_backend.rs b/llama-cpp-bindings/tests/sampler_chain_without_backend.rs
new file mode 100644
index 00000000..f8ff4ee0
--- /dev/null
+++ b/llama-cpp-bindings/tests/sampler_chain_without_backend.rs
@@ -0,0 +1,24 @@
+use anyhow::Result;
+use llama_cpp_bindings::sampling::LlamaSampler;
+use llama_cpp_bindings::token::LlamaToken;
+use llama_cpp_bindings::token::data::LlamaTokenData;
+use llama_cpp_bindings::token::data_array::LlamaTokenDataArray;
+
+#[test]
+fn sampler_chain_applies_without_initialized_backend() -> Result<()> {
+    let sampler_chain = LlamaSampler::chain_simple([LlamaSampler::greedy()?])?;
+    let mut candidates = LlamaTokenDataArray::new(
+        vec![
+            LlamaTokenData::new(LlamaToken::new(0), 1.0, 0.0),
+            LlamaTokenData::new(LlamaToken::new(1), 5.0, 0.0),
+            LlamaTokenData::new(LlamaToken::new(2), 3.0, 0.0),
+        ],
+        false,
+    );
+
+    candidates.apply_sampler(&sampler_chain)?;
+
+    assert_eq!(candidates.selected_token(), Some(LlamaToken::new(1)));
+
+    Ok(())
+}