diff --git a/crates/ruff_benchmark/Cargo.toml b/crates/ruff_benchmark/Cargo.toml
index 9df32cd5ee..9d92fe5c9a 100644
--- a/crates/ruff_benchmark/Cargo.toml
+++ b/crates/ruff_benchmark/Cargo.toml
@@ -66,4 +66,4 @@ codspeed = ["codspeed-criterion-compat"]
 mimalloc = { workspace = true }
 
 [target.'cfg(all(not(target_os = "windows"), not(target_os = "openbsd"), any(target_arch = "x86_64", target_arch = "aarch64", target_arch = "powerpc64")))'.dev-dependencies]
-tikv-jemallocator = { workspace = true }
+tikv-jemallocator = { workspace = true, features = ["unprefixed_malloc_on_supported_platforms"] }
diff --git a/crates/ruff_benchmark/benches/linter.rs b/crates/ruff_benchmark/benches/linter.rs
index dc27674ade..ce4d055cb9 100644
--- a/crates/ruff_benchmark/benches/linter.rs
+++ b/crates/ruff_benchmark/benches/linter.rs
@@ -28,6 +28,24 @@ static GLOBAL: mimalloc::MiMalloc = mimalloc::MiMalloc;
 #[global_allocator]
 static GLOBAL: tikv_jemallocator::Jemalloc = tikv_jemallocator::Jemalloc;
 
+// Disable decay after 10s because it can show up as *random* slow allocations
+// in benchmarks. We don't need purging in benchmarks because it isn't important
+// to give unallocated pages back to the OS.
+// https://jemalloc.net/jemalloc.3.html#opt.dirty_decay_ms
+#[cfg(all(
+    not(target_os = "windows"),
+    not(target_os = "openbsd"),
+    any(
+        target_arch = "x86_64",
+        target_arch = "aarch64",
+        target_arch = "powerpc64"
+    )
+))]
+#[allow(non_upper_case_globals)]
+#[export_name = "malloc_conf"]
+#[allow(unsafe_code)]
+pub static malloc_conf: &[u8] = b"dirty_decay_ms:-1,muzzy_decay_ms:-1\0";
+
 fn create_test_cases() -> Result<Vec<TestCase>, TestFileDownloadError> {
     Ok(vec![
         TestCase::fast(TestFile::try_download("numpy/globals.py", "https://raw.githubusercontent.com/numpy/numpy/89d64415e349ca75a25250f22b874aa16e5c0973/numpy/_globals.py")?),