Merge pull request #2574 from fitzgen/randomize-location-of-heap-objects

wasmtime-bench-api: Randomize the locations of heap objects
bytecodealliance · Jan 13, 2021 · 90b80a2 · 90b80a2
2 parents 47ff726 + bc6dc08
commit 90b80a2
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Showing 3 changed files with 25 additions and 1 deletion.
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/crates/bench-api/Cargo.toml b/crates/bench-api/Cargo.toml
@@ -16,10 +16,13 @@ crate-type = ["rlib", "cdylib"]
 
 [dependencies]
 anyhow = "1.0"
+shuffling-allocator = { version = "1.1.1", optional = true }
 wasmtime = { path = "../wasmtime", default-features = false }
 wasmtime-wasi = { path = "../wasi" }
 wasi-common = { path = "../wasi-common" }
 
-
 [dev-dependencies]
 wat = "1.0"
+
+[features]
+default = ["shuffling-allocator"]
diff --git a/crates/bench-api/src/lib.rs b/crates/bench-api/src/lib.rs
@@ -83,6 +83,14 @@ pub type ExitCode = c_int;
 pub const OK: ExitCode = 0;
 pub const ERR: ExitCode = -1;
 
+// Randomize the location of heap objects to avoid accidental locality being an
+// uncontrolled variable that obscures performance evaluation in our
+// experiments.
+#[cfg(feature = "shuffling-allocator")]
+#[global_allocator]
+static ALLOC: shuffling_allocator::ShufflingAllocator<std::alloc::System> =
+    shuffling_allocator::wrap!(&std::alloc::System);
+
 /// Exposes a C-compatible way of creating the engine from the bytes of a single
 /// Wasm module.
 ///