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Signed-off-by: Daxin Wang <daxinwang@harmonycloud.cn>

collector/pkg/component/consumer/exporter/cameraexporter/filewriter.go

@@ -124,6 +124,8 @@ func (fw *fileWriter) rotateFiles(baseDir string) error {
 		return nil
 	}
 	// Remove the older files and remove half of them one time to decrease the frequency
+	// of deleting files. Note this is different from rotating log files. For log files,
+	// we could delete one file at a time because the action "rotate" is in a low frequency.
 	toBeRotated = toBeRotated[:len(toBeRotated)-fw.config.MaxFileCount/2+1]
 	// Remove the stale files asynchronously
 	go func() {
@@ -135,7 +137,8 @@ func (fw *fileWriter) rotateFiles(baseDir string) error {
 	return nil
 }
 
-// getDirEntryInTimeOrder returns the directory entries slice in chronological order
+// getDirEntryInTimeOrder returns the directory entries slice in chronological order.
+// The result files are sorted based on their modification time.
 func getDirEntryInTimeOrder(path string) ([]os.DirEntry, error) {
 	f, err := os.Open(path)
 	if err != nil {
@@ -148,6 +151,9 @@ func getDirEntryInTimeOrder(path string) ([]os.DirEntry, error) {
 		}
 	}(f)
 	dirs, err := f.ReadDir(-1)
+	// Sort the files based on their modification time. We don't sort them based on the
+	// timestamp in the file name because they are similar but the later one costs more CPU
+	// considering that we have to split the file name first.
 	sort.Slice(dirs, func(i, j int) bool {
 		fileInfoA, err := dirs[i].Info()
 		if err != nil {