package runtime

import (
	"internal/abi"
	"internal/goarch"
	"unsafe"
)

//go:linkname runtime_debug_WriteHeapDump runtime/debug.WriteHeapDump
func runtime_debug_WriteHeapDump(fd uintptr) {
	stw := stopTheWorld(stwWriteHeapDump)

	// Keep m on this G's stack instead of the system stack.
	// Both readmemstats_m and writeheapdump_m have pretty large
	// peak stack depths and we risk blowing the system stack.

	// system. We never release spine memory because there could be
	// concurrent lock-free access and we're likely to reuse it
	// anyway. (In principle, we could do this during STW.)

	spineLock mutex
	spine     atomicSpanSetSpinePointer // *[N]atomic.Pointer[spanSetBlock]
	spineLen  atomic.Uintptr            // Spine array length

// writeProcStatusForP emits a ProcStatus event for the provided p based on its status.
//
// The caller must fully own pp and it must be prevented from transitioning (e.g. this can be
// called by a forEachP callback or from a STW).
func (w traceWriter) writeProcStatusForP(pp *p, inSTW bool) traceWriter {
	if !pp.trace.acquireStatus(w.gen) {
		return w
	}
	var status traceProcStatus
	switch pp.status {
	case _Pidle, _Pgcstop:

	}
	t.Errorf(`time.Sleep did not contribute enough to "idle" class: minimum idle time = %.5fs`, minIdleCPUSeconds)
}

// Call f() and verify that the correct STW metrics increment. If isGC is true,
// fn triggers a GC STW. Otherwise, fn triggers an other STW.
func testSchedPauseMetrics(t *testing.T, fn func(t *testing.T), isGC bool) {
	m := []metrics.Sample{
		{Name: "/sched/pauses/stopping/gc:seconds"},

	trace.seqGC++
}

// STWStart traces a STWBegin event.
func (tl traceLocker) STWStart(reason stwReason) {
	// Although the current P may be in _Pgcstop here, we model the P as running during the STW. This deviates from the
	// runtime's state tracking, but it's more accurate and doesn't result in any loss of information.

  the locked region, reads do not need to be atomic, but the write
  does. Outside the locked region, reads need to be atomic.

* Reads that only happen during STW, where no writes can happen during
  STW, do not need to be atomic.

That said, the advice from the Go memory model stands: "Don't be
[too] clever." The performance of the runtime matters, but its
robustness matters more.

			t.Errorf("bucket overfilled should have overflow %d, found %d", expect, l.Overflow())
		}
		if t.Failed() {
			t.FailNow()
		}

		// Make sure the STW adds to the bucket.
		l.FinishGCTransition(advance(5 * time.Millisecond))
		if l.Fill() != l.Capacity() {
			t.Errorf("failed to maintain fill to capacity %d, got fill %d", l.Capacity(), l.Fill())
		}
		if !l.Limiting() {

//
//	semacquire(&worldsema, 0)
//	m.preemptoff = "reason"
//	var stw worldStop
//	systemstack(func() {
//		stw = stopTheWorldWithSema(reason)
//	})
//
// When finished, the caller must either call startTheWorld or undo
// these three operations separately:
//
//	m.preemptoff = ""
//	systemstack(func() {
//		now = startTheWorldWithSema(stw)
//	})
//	semrelease(&worldsema)
//

		# MB globals scannable global size, or /gc/scan/globals:bytes
		# P          number of processors used, or /sched/gomaxprocs:threads
	The phases are stop-the-world (STW) sweep termination, concurrent
	mark and scan, and STW mark termination. The CPU times
	for mark/scan are broken down in to assist time (GC performed in
	line with allocation), background GC time, and idle GC time.

	case LWA, LWAX, LWAUX:
		return true
	case LD, LDU, LDX, LDUX:
		return true
	case LQ:
		return true
	case STB, STBU, STBX, STBUX:
		return true
	case STH, STHU, STHX, STHUX:
		return true
	case STW, STWU, STWX, STWUX:
		return true
	case STD, STDU, STDX, STDUX:
		return true
	case STQ:
		return true
	case LHBRX, LWBRX, STHBRX, STWBRX:
		return true
	case LBARX, LWARX, LHARX, LDARX:
		return true