diff --git a/Makefile b/Makefile
index 98e83c664..fb6ace212 100644
--- a/Makefile
+++ b/Makefile
@@ -34,6 +34,7 @@ SUBMAKE := $(MAKE) --print-directory
 .SUFFIXES:
 
 BUILDFLAGS := --release --strip
+DEVFLAGS :=
 RUNFLAGS :=
 CHECKABLE_PY := pylib qt
 CHECKABLE_RS := rslib
@@ -66,7 +67,7 @@ develop: pyenv buildhash prepare
 	@set -eo pipefail && \
 	. "${ACTIVATE_SCRIPT}" && \
 	for dir in $(DEVEL); do \
-		$(SUBMAKE) -C $$dir develop BUILDFLAGS="$(BUILDFLAGS)"; \
+		$(SUBMAKE) -C $$dir develop DEVFLAGS="$(DEVFLAGS)"; \
 	done
 
 .PHONY: run
diff --git a/README.development b/README.development
index ac82b6b5a..da92684af 100644
--- a/README.development
+++ b/README.development
@@ -64,9 +64,13 @@ Use 'make clean' to remove some generated files.
 Performance
 ------------
 
-'make run' builds the Rust libraries in unoptimized debug mode. Before doing
-any performance testing, please make sure you make a release build with
-'make build', and install the resulting .whl files with pip.
+'make run' builds the Rust libraries in unoptimized debug mode by default.
+Before doing any performance testing, please make sure you make a release
+build with 'make build' and install the resulting .whl files, or use
+make run with the following command:
+
+touch rspy/src/lib.rs
+make run DEVFLAGS="--release --strip"
 
 PyQt
 -----
diff --git a/rspy/Makefile b/rspy/Makefile
index 078e91386..798a67515 100644
--- a/rspy/Makefile
+++ b/rspy/Makefile
@@ -24,6 +24,7 @@ $(shell mkdir -p .build ../dist)
 
 OUTDIR := ../dist
 BUILDFLAGS := --release --strip
+DEVFLAGS :=
 RSPY_TARGET_DIR ?= target
 
 QT_FTL_TEMPLATES := ../qt/ftl
@@ -45,7 +46,7 @@ DEPS := .build/tools .build/vernum ../meta/buildhash \
 .build/develop: $(DEPS)
 	touch ../proto/backend.proto
 	FTL_TEMPLATE_DIRS="$(QT_FTL_TEMPLATES)" FTL_LOCALE_DIRS="$(QT_FTL_LOCALES)" \
-		CARGO_TARGET_DIR="$(RSPY_TARGET_DIR)" maturin develop
+		CARGO_TARGET_DIR="$(RSPY_TARGET_DIR)" maturin develop $(DEVFLAGS)
 	touch $@
 
 build: $(DEPS)