diff --git a/cl/compile.go b/cl/compile.go
index 3b631e69..2d20d234 100644
--- a/cl/compile.go
+++ b/cl/compile.go
@@ -100,10 +100,11 @@ func ignoreName(name string) bool {
 		strings.HasPrefix(name, "arena.") || strings.HasPrefix(name, "maps.") ||
 		strings.HasPrefix(name, "time.") || strings.HasPrefix(name, "syscall.") ||
 		strings.HasPrefix(name, "os.") || strings.HasPrefix(name, "plugin.") ||
-		strings.HasPrefix(name, "reflect.") || strings.HasPrefix(name, "errors.") {
+		strings.HasPrefix(name, "reflect.") || strings.HasPrefix(name, "errors.") ||
+		strings.HasPrefix(name, "sync.") {
 		return true // TODO(xsw)
 	}
-	return inPkg(name, "runtime") || inPkg(name, "sync")
+	return inPkg(name, "runtime")
 }
 
 func inPkg(name, pkg string) bool {
@@ -157,6 +158,8 @@ type context struct {
 
 	inits []func()
 	phis  []func()
+
+	skipall bool
 }
 
 func (p *context) inMain(instr ssa.Instruction) bool {
@@ -1048,7 +1051,9 @@ func NewPackageEx(prog llssa.Program, pkg, alt *ssa.Package, files []*ast.File)
 		processPkg(ctx, ret, alt)
 		ctx.skips = skips
 	}
-	processPkg(ctx, ret, pkg)
+	if !ctx.skipall {
+		processPkg(ctx, ret, pkg)
+	}
 	for len(ctx.inits) > 0 {
 		inits := ctx.inits
 		ctx.inits = nil
diff --git a/cl/import.go b/cl/import.go
index c1217778..72addadd 100644
--- a/cl/import.go
+++ b/cl/import.go
@@ -193,10 +193,12 @@ func (p *context) initFiles(pkgPath string, files []*ast.File) {
 	}
 }
 
+// llgo:skip symbol1 symbol2 ...
+// llgo:skipall
 func (p *context) collectSkipNames(line string) {
 	const (
-		skip  = "//llgo:skip "
-		skip2 = "// llgo:skip "
+		skip  = "//llgo:skip"
+		skip2 = "// llgo:skip"
 	)
 	if strings.HasPrefix(line, skip2) {
 		p.collectSkip(line, len(skip2))
@@ -206,7 +208,15 @@ func (p *context) collectSkipNames(line string) {
 }
 
 func (p *context) collectSkip(line string, prefix int) {
-	names := strings.Split(line[prefix:], " ")
+	line = line[prefix:]
+	if line == "all" {
+		p.skipall = true
+		return
+	}
+	if len(line) == 0 || line[0] != ' ' {
+		return
+	}
+	names := strings.Split(line[1:], " ")
 	for _, name := range names {
 		if name != "" {
 			p.skips[name] = none{}
diff --git a/internal/build/build.go b/internal/build/build.go
index 552a71f1..9568246f 100644
--- a/internal/build/build.go
+++ b/internal/build/build.go
@@ -22,6 +22,7 @@ import (
 	"go/token"
 	"go/types"
 	"io"
+	"log"
 	"os"
 	"os/exec"
 	"path"
@@ -159,6 +160,10 @@ func Do(args []string, conf *Config) {
 
 	var runtimeFiles []string
 	if needRt {
+		// TODO(xsw): maybe we need trace runtime sometimes
+		llssa.SetDebug(0)
+		cl.SetDebug(0)
+
 		skip := make(map[string]bool)
 		for _, v := range pkgs {
 			skip[v.PkgPath] = true
@@ -208,7 +213,7 @@ const (
 
 func buildAllPkgs(prog llssa.Program, imp importer, initial []*packages.Package, skip map[string]bool, mode Mode, verbose bool) (pkgs []*aPackage) {
 	// Create SSA-form program representation.
-	ssaProg, pkgs, errPkgs := allPkgs(imp, initial, ssaBuildMode)
+	ssaProg, pkgs, errPkgs := allPkgs(imp, initial, ssaBuildMode, verbose)
 	ssaProg.Build()
 	for _, errPkg := range errPkgs {
 		for _, err := range errPkg.Errors {
@@ -394,7 +399,7 @@ func buildPkg(prog llssa.Program, aPkg *aPackage, mode Mode, verbose bool) {
 
 func canSkipToBuild(pkgPath string) bool {
 	switch pkgPath {
-	case "unsafe", "runtime", "errors", "sync", "sync/atomic":
+	case "unsafe", "runtime", "errors", "sync":
 		return true
 	default:
 		return strings.HasPrefix(pkgPath, "internal/") ||
@@ -419,7 +424,7 @@ var hasAltPkg = map[string]none{
 
 type importer = func(pkgPath string) *packages.Package
 
-func allPkgs(imp importer, initial []*packages.Package, mode ssa.BuilderMode) (prog *ssa.Program, all []*aPackage, errs []*packages.Package) {
+func allPkgs(imp importer, initial []*packages.Package, mode ssa.BuilderMode, verbose bool) (prog *ssa.Program, all []*aPackage, errs []*packages.Package) {
 	var fset *token.FileSet
 	if len(initial) > 0 {
 		fset = initial[0].Fset
@@ -433,9 +438,12 @@ func allPkgs(imp importer, initial []*packages.Package, mode ssa.BuilderMode) (p
 			var ssaPkg = prog.CreatePackage(p.Types, p.Syntax, p.TypesInfo, true)
 			if imp != nil {
 				if _, ok := hasAltPkg[p.PkgPath]; ok {
+					if verbose {
+						log.Println("==> Patching", p.PkgPath)
+					}
 					altPkgPath := "github.com/goplus/llgo/internal/lib/" + p.PkgPath
 					if altPkg = imp(altPkgPath); altPkg != nil { // TODO(xsw): how to minimize import times
-						altSSA = createAltSSAPkg(prog, altPkg)
+						altSSA = createAltSSAPkg(prog, altPkg, verbose)
 					}
 				}
 			}
@@ -447,14 +455,17 @@ func allPkgs(imp importer, initial []*packages.Package, mode ssa.BuilderMode) (p
 	return
 }
 
-func createAltSSAPkg(prog *ssa.Program, alt *packages.Package) *ssa.Package {
+func createAltSSAPkg(prog *ssa.Program, alt *packages.Package, verbose bool) *ssa.Package {
 	altPath := alt.Types.Path()
 	altSSA := prog.ImportedPackage(altPath)
 	if altSSA == nil {
 		packages.Visit([]*packages.Package{alt}, nil, func(p *packages.Package) {
 			pkgTypes := p.Types
 			if pkgTypes != nil && !p.IllTyped {
-				if prog.ImportedPackage(pkgTypes.Path()) == nil {
+				if pkgPath := pkgTypes.Path(); prog.ImportedPackage(pkgPath) == nil {
+					if verbose {
+						log.Println("==> SSAPackage", pkgPath)
+					}
 					prog.CreatePackage(pkgTypes, p.Syntax, p.TypesInfo, true)
 				}
 			}
diff --git a/internal/lib/sync/atomic/atomic.go b/internal/lib/sync/atomic/atomic.go
index f62c5356..42e74b7d 100644
--- a/internal/lib/sync/atomic/atomic.go
+++ b/internal/lib/sync/atomic/atomic.go
@@ -16,7 +16,7 @@
 
 package atomic
 
-// llgo:skip init
+// llgo:skipall
 import (
 	_ "unsafe"
 )