diff --git a/tools/perf/Makefile b/tools/perf/Makefile
index 74f52d8..9580ebe 100644
--- a/tools/perf/Makefile
+++ b/tools/perf/Makefile
@@ -30,12 +30,19 @@
   endif
 endif
 
+#
+# Only pass canonical directory names as the output directory:
+#
+ifneq ($(O),)
+  FULL_O := $(shell readlink -f $(O))
+endif
+
 define print_msg
   @printf '    BUILD: Doing '\''make \033[33m-j'$(JOBS)'\033[m'\'' parallel build\n'
 endef
 
 define make
-  @$(MAKE) -f Makefile.perf --no-print-directory -j$(JOBS) O=$(O) $@
+  @$(MAKE) -f Makefile.perf --no-print-directory -j$(JOBS) O=$(FULL_O) $@
 endef
 
 #