{name: "dontfreezetheworld", value: &debug.dontfreezetheworld},
	{name: "efence", value: &debug.efence},
	{name: "gccheckmark", value: &debug.gccheckmark},
	{name: "gcpacertrace", value: &debug.gcpacertrace},
	{name: "gcshrinkstackoff", value: &debug.gcshrinkstackoff},
	{name: "gcstoptheworld", value: &debug.gcstoptheworld},
	{name: "gctrace", value: &debug.gctrace},

	second mark pass while the world is stopped.  If the second
	pass finds a reachable object that was not found by concurrent
	mark, the garbage collector will panic.

	gcpacertrace: setting gcpacertrace=1 causes the garbage collector to
	print information about the internal state of the concurrent pacer.

	gcshrinkstackoff: setting gcshrinkstackoff=1 disables moving goroutines

	}

	// Compute initial values for controls that are updated
	// throughout the cycle.
	c.dedicatedMarkWorkersNeeded.Store(dedicatedMarkWorkersNeeded)
	c.revise()

	if debug.gcpacertrace > 0 {
		heapGoal := c.heapGoal()
		assistRatio := c.assistWorkPerByte.Load()
		print("pacer: assist ratio=", assistRatio,
			" (scan ", gcController.heapScan.Load()>>20, " MB in ",
			work.initialHeapLive>>20, "->",

			throw("mismatched begin/end of activeSweep")
		}
		if a.state.CompareAndSwap(state, state-1) {
			if state != sweepDrainedMask {
				return
			}
			if debug.gcpacertrace > 0 {
				live := gcController.heapLive.Load()