## Compiler {#compiler}

The build time overhead to building with [Profile Guided Optimization](/doc/pgo) has been reduced significantly.
Previously, large builds could see 100%+ build time increase from enabling PGO.
In Go 1.23, overhead should be in the single digit percentages.

## Assembler {#assembler}

pkg syscall (netbsd-arm64-cgo), const SYS_PREADV = 289
pkg syscall (netbsd-arm64-cgo), const SYS_PREADV ideal-int
pkg syscall (netbsd-arm64-cgo), const SYS_PROFIL = 44
pkg syscall (netbsd-arm64-cgo), const SYS_PROFIL ideal-int
pkg syscall (netbsd-arm64-cgo), const SYS_PSELECT = 436
pkg syscall (netbsd-arm64-cgo), const SYS_PSELECT ideal-int
pkg syscall (netbsd-arm64-cgo), const SYS_PSET_ASSIGN = 414

	}

	mps := detectMobileProvisionFiles(udids)
	if len(mps) == 0 {
		fail("did not find mobile provision matching device udids %q", udids)
	}

	fmt.Println("# Available provisioning profiles below.")
	fmt.Println("# NOTE: Any existing app on the device with the app id specified by GOIOS_APP_ID")
	fmt.Println("# will be overwritten when running Go programs.")
	for _, mp := range mps {
		fmt.Println()

)

var DebugFlags struct {
	MayMoreStack string `help:"call named function before all stack growth checks"`
	PCTab        string `help:"print named pc-value table\nOne of: pctospadj, pctofile, pctoline, pctoinline, pctopcdata"`
}

var (
	D        MultiFlag
	I        MultiFlag
	PrintOut int
	DebugV   bool
)

func init() {

pkg syscall (darwin-386), const SYS_ACCESS = 33
pkg syscall (darwin-386), const SYS_ACCESS_EXTENDED = 284
pkg syscall (darwin-386), const SYS_ACCT = 51
pkg syscall (darwin-386), const SYS_ADD_PROFIL = 176
pkg syscall (darwin-386), const SYS_ADJTIME = 140
pkg syscall (darwin-386), const SYS_AIO_CANCEL = 316
pkg syscall (darwin-386), const SYS_AIO_ERROR = 317
pkg syscall (darwin-386), const SYS_AIO_FSYNC = 313

or if you rebuild from sources by running all.bash (see doc/install.html). You should also add the Go binary directory $GOROOT/bin to your shell's path. For example, if you extracted the tar file into $HOME/go, you might put the following in your .profile: export GOROOT=$HOME/go export PATH=$PATH:$GOROOT/bin See doc/install.html for more details....

pkg syscall (freebsd-386-cgo), const SYS_POSIX_OPENPT ideal-int
pkg syscall (freebsd-386-cgo), const SYS_PREAD ideal-int
pkg syscall (freebsd-386-cgo), const SYS_PREADV ideal-int
pkg syscall (freebsd-386-cgo), const SYS_PROFIL ideal-int
pkg syscall (freebsd-386-cgo), const SYS_PSELECT ideal-int
pkg syscall (freebsd-386-cgo), const SYS_PTRACE ideal-int
pkg syscall (freebsd-386-cgo), const SYS_PWRITE ideal-int

[GC guide](/doc/gc-guide#Linux_transparent_huge_pages), or switch to a Linux
distribution that disables transparent huge pages altogether.

Go 1.22 added contention on runtime-internal locks to the [`mutex`
profile](/pkg/runtime/pprof#Profile). Contention on these locks is always
reported at `runtime._LostContendedRuntimeLock`. Complete stack traces of
runtime locks can be enabled with the [`runtimecontentionstacks`

Their values, defined in the standard <code>#include</code>  file <code>textflag.h</code>, are:
</p>

<ul>
<li>
<code>NOPROF</code> = 1
<br>
(For <code>TEXT</code> items.)
Don't profile the marked function.  This flag is deprecated.
</li>
<li>
<code>DUPOK</code> = 2
<br>
It is legal to have multiple instances of this symbol in a single binary.
The linker will choose one of the duplicates to use.

pkg runtime/pprof, func Lookup(string) *Profile
pkg runtime/pprof, func NewProfile(string) *Profile
pkg runtime/pprof, func Profiles() []*Profile
pkg runtime/pprof, func StartCPUProfile(io.Writer) error
pkg runtime/pprof, func StopCPUProfile()
pkg runtime/pprof, func WriteHeapProfile(io.Writer) error
pkg runtime/pprof, method (*Profile) Add(interface{}, int)
pkg runtime/pprof, method (*Profile) Count() int