{name: "runtimecontentionstacks", atomic: &debug.runtimeContentionStacks},
	{name: "sbrk", value: &debug.sbrk},
	{name: "scavtrace", value: &debug.scavtrace},
	{name: "scheddetail", value: &debug.scheddetail},
	{name: "schedtrace", value: &debug.schedtrace},
	{name: "traceadvanceperiod", value: &debug.traceadvanceperiod},
	{name: "traceallocfree", atomic: &debug.traceallocfree},

		#% util            the fraction of all unscavenged heap memory which is in-use
	If the line ends with "(forced)", then scavenging was forced by a
	debug.FreeOSMemory() call.

	scheddetail: setting schedtrace=X and scheddetail=1 causes the scheduler to emit
	detailed multiline info every X milliseconds, describing state of the scheduler,
	processors, threads and goroutines.

	}

	switch gp.m.dying {
	case 0:
		// Setting dying >0 has the side-effect of disabling this G's writebuf.
		gp.m.dying = 1
		panicking.Add(1)
		lock(&paniclk)
		if debug.schedtrace > 0 || debug.scheddetail > 0 {
			schedtrace(true)
		}
		freezetheworld()
		return true
	case 1:
		// Something failed while panicking.
		// Just print a stack trace and exit.
		gp.m.dying = 2

			unlock(&sched.lock)
			throw("checkdead: runnable g")
		}
	})
	if grunning == 0 { // possible if main goroutine calls runtime·Goexit()
		unlock(&sched.lock) // unlock so that GODEBUG=scheddetail=1 doesn't hang
		fatal("no goroutines (main called runtime.Goexit) - deadlock!")
	}

	// Maybe jump time forward for playground.
	if faketime != 0 {
		if when := timeSleepUntil(); when < maxWhen {