diff --git a/tools/src/cmd/time-cmd/main.go b/tools/src/cmd/time-cmd/main.go
new file mode 100644
index 0000000000..fb1d08b355
--- /dev/null
+++ b/tools/src/cmd/time-cmd/main.go
@@ -0,0 +1,154 @@
+// Copyright 2023 The Tint Authors.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// time-cmd runs a given command for each file found in a glob, returning the
+// sorted run times.
+package main
+
+import (
+	"flag"
+	"fmt"
+	"math/rand"
+	"os"
+	"os/exec"
+	"sort"
+	"strings"
+	"text/tabwriter"
+	"time"
+
+	"dawn.googlesource.com/dawn/tools/src/fileutils"
+	"dawn.googlesource.com/dawn/tools/src/glob"
+	"dawn.googlesource.com/dawn/tools/src/progressbar"
+)
+
+func main() {
+	if err := run(); err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+}
+func run() error {
+	flag.Usage = func() {
+		out := flag.CommandLine.Output()
+		fmt.Fprintf(out, "time-cmd runs a given command for each file found in a glob, returning the sorted run times..\n")
+		fmt.Fprintf(out, "\n")
+		fmt.Fprintf(out, "Usage:\n")
+		fmt.Fprintf(out, "  time-cmd [flags] <cmd [args...]>\n")
+		fmt.Fprintf(out, "\n")
+		fmt.Fprintf(out, "cmd is the path to the command to run\n")
+		fmt.Fprintf(out, "args are optional command line arguments to 'cmd'\n")
+		fmt.Fprintf(out, "args should include '%%F' for the globbed file path\n")
+		fmt.Fprintf(out, "\n")
+		fmt.Fprintf(out, "flags may be any combination of:\n")
+		flag.PrintDefaults()
+	}
+	var fileGlob string
+	var top, runs int
+	flag.StringVar(&fileGlob, "f", "", "the files to glob. Paths are relative to the dawn root directory")
+	flag.IntVar(&top, "top", 0, "displays the longest N results")
+	flag.IntVar(&runs, "runs", 1, "takes the average of N runs")
+	flag.Parse()
+
+	args := flag.Args()
+	if fileGlob == "" {
+		flag.Usage()
+		return fmt.Errorf("Missing --f flag")
+	}
+	if len(args) < 1 {
+		flag.Usage()
+		return fmt.Errorf("Missing command")
+	}
+
+	fileGlob = fileutils.ExpandHome(fileGlob)
+
+	exe, err := exec.LookPath(fileutils.ExpandHome(args[0]))
+	if err != nil {
+		return fmt.Errorf("could not find executable '%v'", args[0])
+	}
+
+	files, err := glob.Glob(fileGlob)
+	if err != nil {
+		return err
+	}
+
+	if len(files) == 0 {
+		fmt.Println("no files found with glob '" + fileGlob + "'")
+		return nil
+	}
+
+	pb := progressbar.New(os.Stdout, nil)
+	defer pb.Stop()
+
+	type Result struct {
+		file string
+		time time.Duration
+		errs []error
+	}
+	status := progressbar.Status{
+		Total:    len(files) * runs,
+		Segments: []progressbar.Segment{{Color: progressbar.Green}, {Color: progressbar.Red}},
+	}
+	segSuccess := &status.Segments[0]
+	segError := &status.Segments[1]
+
+	results := make([]Result, len(files))
+	for i, f := range files {
+		results[i].file = f
+	}
+
+	for run := 0; run < runs; run++ {
+		rand.Shuffle(len(results), func(i, j int) { results[i], results[j] = results[j], results[i] })
+		for i := range results {
+			result := &results[i]
+			exeArgs := make([]string, len(args[1:]))
+			for i, arg := range args[1:] {
+				exeArgs[i] = strings.ReplaceAll(arg, "%F", result.file)
+			}
+			cmd := exec.Command(exe, exeArgs...)
+
+			start := time.Now()
+			out, err := cmd.CombinedOutput()
+			time := time.Since(start)
+
+			result.time += time
+			if err != nil {
+				result.errs = append(result.errs, fmt.Errorf("%v", string(out)))
+				segError.Count++
+			} else {
+				segSuccess.Count++
+			}
+			pb.Update(status)
+		}
+	}
+
+	sort.Slice(results, func(i, j int) bool { return results[i].time > results[j].time })
+
+	if top > 0 {
+		if top > len(results) {
+			top = len(results)
+		}
+		results = results[:top]
+	}
+
+	tw := tabwriter.NewWriter(os.Stdout, 1, 0, 1, ' ', 0)
+	defer tw.Flush()
+	for i, r := range results {
+		s := ""
+		if len(r.errs) > 0 {
+			s = fmt.Sprint(r.errs)
+		}
+		fmt.Fprintf(tw, "%v\t%v\t%v\t%v\n", i, r.time/time.Duration(runs), r.file, s)
+	}
+	return nil
+}
diff --git a/tools/src/glob/glob.go b/tools/src/glob/glob.go
index 829f923238..4d61afa1b1 100644
--- a/tools/src/glob/glob.go
+++ b/tools/src/glob/glob.go
@@ -27,6 +27,43 @@ import (
 	"dawn.googlesource.com/dawn/tools/src/match"
 )
 
+// Glob returns all the strings that match the given filepath glob
+func Glob(str string) ([]string, error) {
+	abs, err := filepath.Abs(str)
+	if err != nil {
+		return nil, err
+	}
+	root, glob := "", ""
+	// Look for rightmost directory delimiter that's left of a wildcard. Use
+	// that to split the 'root' from the match 'glob'.
+	for i, c := range abs {
+		switch c {
+		case '/':
+			root, glob = abs[:i], abs[i+1:]
+		case '*', '?':
+			test, err := match.New(glob)
+			if err != nil {
+				return nil, err
+			}
+			files, err := Scan(root, Config{Paths: searchRules{
+				func(path string, cond bool) bool { return test(path) },
+			}})
+			if err != nil {
+				return nil, err
+			}
+			for i, f := range files {
+				files[i] = filepath.Join(root, f) // rel -> abs
+			}
+			return files, nil
+		}
+	}
+	// No wildcard found. Does the file exist at 'str'?
+	if s, err := os.Stat(str); err != nil && !s.IsDir() {
+		return []string{str}, nil
+	}
+	return []string{}, nil
+}
+
 // Scan walks all files and subdirectories from root, returning those
 // that Config.shouldExamine() returns true for.
 func Scan(root string, cfg Config) ([]string, error) {
@@ -155,12 +192,15 @@ func (l *searchRules) UnmarshalJSON(body []byte) error {
 				tests[i] = test
 			}
 			*l = append(*l, func(path string, cond bool) bool {
+				if cond {
+					return true
+				}
 				for _, test := range tests {
 					if test(path) {
 						return true
 					}
 				}
-				return cond
+				return false
 			})
 		case len(rule.Exclude) > 0:
 			tests := make([]match.Test, len(rule.Exclude))
@@ -172,12 +212,15 @@ func (l *searchRules) UnmarshalJSON(body []byte) error {
 				tests[i] = test
 			}
 			*l = append(*l, func(path string, cond bool) bool {
+				if !cond {
+					return false
+				}
 				for _, test := range tests {
 					if test(path) {
 						return false
 					}
 				}
-				return cond
+				return true
 			})
 		}
 	}