Is it unheard of that class singleton method does not return class in core?
Do we need monotonic time?
Can we reasonably provide it to multiple OS?
In which class should it appear?

I feel pretty much 100% of timers in every code are broken, because
UTC and consequently unixtime is not monotonic today, it might be in
few years time.
Some languages offer nice timestamp function to monotonic time, ruby does not.


Ghetto example of implementation:

[ytti@lintukoto ~/tmp/ruby-2.1.2]% git diff|cat
diff --git a/time.c b/time.c
index 878b7ed..2e5443b 100644
--- a/time.c
+++ b/time.c
@@ -3132,6 +3132,13 @@ time_s_mktime(int argc, VALUE *argv, VALUE klass)
     return time_utc_or_local(argc, argv, FALSE, klass);
 }

+static VALUE
+time_s_monotonic(VALUE klass) {
+  struct timespec ts;
+  clock_gettime(CLOCK_MONOTONIC, &ts);
+  return UINT64toNUM(((long long unsigned) ts.tv_sec*1000000000) +
(long long unsigned) ts.tv_nsec);
+}
+
 /*
  *  call-seq:
  *     time.to_i   -> int
@@ -4939,6 +4946,7 @@ Init_Time(void)
     rb_define_singleton_method(rb_cTime, "gm", time_s_mkutc, -1);
     rb_define_singleton_method(rb_cTime, "local", time_s_mktime, -1);
     rb_define_singleton_method(rb_cTime, "mktime", time_s_mktime, -1);
+    rb_define_singleton_method(rb_cTime, "monotonic", time_s_monotonic, -1);

     rb_define_method(rb_cTime, "to_i", time_to_i, 0);
     rb_define_method(rb_cTime, "to_f", time_to_f, 0);
[ytti@lintukoto ~/tmp/ruby-2.1.2]% ./miniruby -e 'p Time.monotonic';uptime
1602029246189
 09:19:26 up 26 min,  6 users,  load average: 0,22, 0,31, 0,23
[ytti@lintukoto ~/tmp/ruby-2.1.2]%




-- 
  ++ytti