diff --git a/TODO.md b/TODO.md
index a8d0856..0238166 100644
--- a/TODO.md
+++ b/TODO.md
@@ -15,6 +15,7 @@
 
 # Performance
 
+* Use rayon for faster multi-block indexing on multi-core systems
 * Experiment with [sled](https://github.com/spacejam/sled) DB
 
 # Rust