diff --git a/tools/Cargo.toml b/tools/Cargo.toml
index d6ee9c4..7185f3b 100644
--- a/tools/Cargo.toml
+++ b/tools/Cargo.toml
@@ -41,6 +41,9 @@ subplot-build = "0.5.0"
 fehler = "1.0.0"
 subplotlib = "0.5.0"
 
+[profile.release]
+codegen-units = 1
+
 [features]
 default = ["sequoia-openpgp/default"]