[perf] Add more output to perf-tool.

Change-Id: I9ed89a3e0070624876ad7e5a19bbeec5d4464ad6
Reviewed-on: https://skia-review.googlesource.com/c/buildbot/+/310576
Reviewed-by: Joe Gregorio <jcgregorio@google.com>
diff --git a/perf/go/perf-tool/main.go b/perf/go/perf-tool/main.go
index 4b09340..e642a44 100644
--- a/perf/go/perf-tool/main.go
+++ b/perf/go/perf-tool/main.go
@@ -400,6 +400,7 @@
 			return err
 		}
 	}
+	fmt.Printf("Backing up from %v", backupToDate)
 
 	f, err := os.Create(c.Flag(outputFilenameFlag).Value.String())
 	if err != nil {
@@ -433,6 +434,7 @@
 
 	for {
 		if end < 0 {
+			fmt.Println("Finished backing up chunks.")
 			break
 		}
 
@@ -454,7 +456,9 @@
 			if err != nil {
 				return err
 			}
-			if time.Unix(cid.Timestamp, 0).Before(backupToDate) {
+			commitDate := time.Unix(cid.Timestamp, 0)
+			if commitDate.Before(backupToDate) {
+				fmt.Printf("Finished backup: %v < %v", commitDate, backupToDate)
 				goto End
 			}
 			body := allRegressionsForCommitWithCommitNumber{