diff --git a/system-freebsd.go b/system-freebsd.go
index 796dd65..d2e79b5 100644
--- a/system-freebsd.go
+++ b/system-freebsd.go
@@ -1,5 +1,4 @@
 //go:build freebsd 
-
 package hodu
 
 import "syscall"
@@ -13,10 +12,15 @@ import "unsafe"
 //const FREEBSD_CLOCK_MONOTONIC uintptr = C.CLOCK_MONOTONIC
 const CLOCK_MONOTONIC uintptr = 4
 
+// utilize the builtin runtime.nanotime()
+//go:noescape
+//go:linkname nanotime runtime.nanotime
+func nanotime() int64
+
 func monotonic_time() uint64 {
 	var ts syscall.Timespec
 	var errno syscall.Errno
 	_, _, errno = syscall.Syscall(syscall.SYS_CLOCK_GETTIME, CLOCK_MONOTONIC, uintptr(unsafe.Pointer(&ts)), 0)
-	if errno != 0 { return 0 }
+	if errno != 0 { return uint64(nanotime()) }
 	return uint64(ts.Nano())
 }
diff --git a/system-linux.go b/system-linux.go
index efb7866..9c3cb13 100644
--- a/system-linux.go
+++ b/system-linux.go
@@ -1,5 +1,4 @@
 //go:build linux
-
 package hodu
 
 import "syscall"
@@ -13,10 +12,15 @@ import "unsafe"
 //const CLOCK_MONOTONIC uintptr = C.CLOCK_MONOTONIC
 const CLOCK_MONOTONIC uintptr = 1
 
+// utilize the builtin runtime.nanotime()
+//go:noescape
+//go:linkname nanotime runtime.nanotime
+func nanotime() int64
+
 func monotonic_time() uint64 {
 	var ts syscall.Timespec
 	var errno syscall.Errno
 	_, _, errno = syscall.Syscall(syscall.SYS_CLOCK_GETTIME, CLOCK_MONOTONIC, uintptr(unsafe.Pointer(&ts)), 0)
-	if errno != 0 { return 0 }
+	if errno != 0 { return uint64(nanotime()) }
 	return uint64(ts.Nano())
 }