description: New telemetry counter or update on an existing one
title: "x/telemetry/config: proposal title"
labels: ["Telemetry-Proposal"]
projects: ["golang/29"]
body:
- type: textarea
  attributes:
    label: Counter names
    description: Names of counters to add or update.
  validations:
    required: true
- type: textarea
  attributes:
    label: Description
    description: What do these counters measure?
  validations:

Some, such as `http2client` and `http2server`,
will be maintained much longer, even indefinitely.

When possible, each GODEBUG setting has an associated
[runtime/metrics](/pkg/runtime/metrics/) counter
named `/godebug/non-default-behavior/<name>:events`
that counts the number of times a particular program's
behavior has changed based on a non-default value
for that setting.
For example, when `GODEBUG=http2client=0` is set,

determined by how the memory was allocated; it has nothing to do with
the type of the pointer.

Note that values of some Go types, other than the type's zero value,
always include Go pointers. This is true of string, slice, interface,
channel, map, and function types. A pointer type may hold a Go pointer
or a C pointer. Array and struct types may or may not include Go

<p>
A <code>Pointer</code> is a <a href="#Pointer_types">pointer type</a> but a <code>Pointer</code>
value may not be <a href="#Address_operators">dereferenced</a>.
Any pointer or value of <a href="#Types">underlying type</a> <code>uintptr</code> can be converted to
a type of underlying type <code>Pointer</code> and vice versa.
The effect of converting between <code>Pointer</code> and <code>uintptr</code> is implementation-defined.
</p>

the toolchain, such as a frame pointer.
The set of pseudo-registers is the same for all architectures:
</p>

<ul>

<li>
<code>FP</code>: Frame pointer: arguments and locals.
</li>

<li>
<code>PC</code>: Program counter:
jumps and branches.
</li>

<li>
<code>SB</code>: Static base pointer: global symbols.
</li>

<li>

The [SliceAt(typ Type, p unsafe.Pointer, len int)] function
returns a Value representing a slice whose underlying array starts

// const declaration. It is zero-indexed.
const iota = 0 // Untyped int.

// nil is a predeclared identifier representing the zero value for a
// pointer, channel, func, interface, map, or slice type.
var nil Type // Type must be a pointer, channel, func, interface, map, or slice type

// Type is here for the purposes of documentation only. It is a stand-in

handles are equal, allowing programs to deduplicate values and reduce
their memory footprint.
Comparing two `Handle[T]` values is efficient, reducing down to a simple

-->

<p>
A <code>Pointer</code> is a <a href="#Pointer_types">pointer type</a> but a <code>Pointer</code>
value may not be <a href="#Address_operators">dereferenced</a>.
Any pointer or value of <a href="#Core_types">core type</a> <code>uintptr</code> can be
<a href="#Conversions">converted</a> to a type of core type <code>Pointer</code> and vice versa.

		"test.nestedCall",
		"test.testCallbackCallersSEH",
		"test.TestCallbackCallersSEH",
	}
	pc := make([]uintptr, 100)
	n := 0
	nestedCall(func() {
		n = int(C.backtrace(C.DWORD(len(pc)), (*C.PVOID)(unsafe.Pointer(&pc[0]))))
	})
	got := make([]string, 0, n)
	for i := 0; i < n; i++ {
		f := runtime.FuncForPC(pc[i] - 1)
		if f == nil {
			continue
		}
		fname := f.Name()
		switch fname {
		case "goCallback":