In Go 1.23, overhead should be in the single digit percentages.

<!-- https://go.dev/issue/62737 , https://golang.org/cl/576681,  https://golang.org/cl/577615 -->
The compiler in Go 1.23 can now overlap the stack frame slots of local variables
accessed in disjoint regions of a function, which reduces stack usage
for Go applications.

<!-- https://go.dev/cl/577935 -->
For 386 and amd64, the compiler will use information from PGO to align certain

kind: feature
area: traffic-management

releaseNotes:
- |
  **Added** an experimental feature to enable cluster creation on worker threads inline during requests.
  This will save memory and CPU cycles in cases where there are lots of inactive clusters and > 1 worker thread.

//
//   - <StorageConcurrentTasksLimit>
//     Setting reduces the parallel Repository Task slots that offload or write data to object storage. The same user interface
//     setting overwrites the storage-defined setting.
//     Optional value, default 0, range: 0-unlimited (0 equals unlimited, which means the maximum configured repository task
//     slots are used for object offloading or writing)
//
//   - <KbBlockSize>

var Meta struct {
	// List contains the list of currently registered meta-data
	// blobs for the running program.
	List []CovMetaBlob

	// PkgMap records mappings from hard-coded package IDs to
	// slots in the List above.
	PkgMap map[int]int

	// Set to true if we discover a package mapping glitch.
	hardCodedListNeedsUpdating bool
}

// AddMeta is invoked during package "init" functions by the

	// The maximum number of bytes required to hold the encoded type.
	maxBytes := 1 + 5*traceBytesPerNumber + len(typName)

	// Estimate the size of this record. This
	// bound is pretty loose, but avoids counting
	// lots of varint sizes.
	//
	// Add 1 because we might also write a traceAllocFreeTypesBatch byte.
	var flushed bool
	w, flushed = w.ensure(1 + maxBytes)
	if flushed {
		// Annotate the batch as containing types.

		}
	}
}

func TestMergeLocalsIntegration(t *testing.T) {
	testenv.MustHaveGoBuild(t)

	// This test does a build of a specific canned package to
	// check whether merging of stack slots is taking place.
	// The idea is to do the compile with a trace option turned
	// on and then pick up on the frame offsets of specific
	// variables.
	//
	// Stack slot merging is a greedy algorithm, and there can

	}

	// Implementation note: this function would be faster and simpler
	// if we could just zero out the entire counter array, but for the
	// moment we go through and zero out just the slots in the array
	// corresponding to the counter values. We do this to avoid the
	// following bad scenario: suppose that a user builds their Go
	// program with "-cover", and that program has a function (call it

		c0 := substr[0]
		c1 := substr[1]
		i := 0
		t := len(s) - n + 1
		fails := 0
		for i < t {
			if s[i] != c0 {
				// IndexByte is faster than bytealg.IndexString, so use it as long as
				// we're not getting lots of false positives.
				o := IndexByte(s[i+1:t], c0)
				if o < 0 {
					return -1
				}
				i += o + 1
			}
			if s[i+1] == c1 && s[i:i+n] == substr {
				return i
			}
			fails++
			i++

		t.Logf("vmmap output: %s", out)
		if ee, ok := cmdErr.(*exec.ExitError); ok && len(ee.Stderr) > 0 {
			t.Logf("%v: %v\n%s", cmd, cmdErr, ee.Stderr)
			if testing.Short() && strings.Contains(string(ee.Stderr), "No process corpse slots currently available, waiting to get one") {
				t.Skipf("Skipping knwn flake in short test mode")
			}
			retryable = bytes.Contains(ee.Stderr, []byte("resource shortage"))
		}
		t.Logf("%v: %v\n", cmd, cmdErr)

	cases := map[string]struct {
		minMb int64
		maxMb int64
	}{
		// TODO: shrink the ranges here once the active work to reduce binary size is complete
		// For now, having two small a range will result in lots of "merge conflicts"
		"istioctl":    {60, 85},
		"pilot-agent": {20, 24},
		// TODO(https://github.com/kubernetes/kubernetes/issues/101384) bump this down a bit?
		"pilot-discovery": {60, 85},