What constitutes misconduct in a trial if a judge makes disparaging remarks to defense counsel?

"Although the trial court has both the duty and the discretion to control the conduct of the trial [citation], the court 'commits misconduct if it persistently makes discourteous and disparaging remarks to defense counsel so as to discredit the defense or create the impression it is allying itself with the prosecution.' [Citation.]" (People v. Snow (2003) 30 Cal.4th 43, 78.) The reviewing court's "'role... is not to determine whether the trial judge's conduct left something to be desired, or even whether some comments would have been better left unsaid. Rather, we must determine whether the judge's behavior was so prejudicial that it denied [the defendant] a fair, as opposed to a perfect, trial.' [Citation.]" (Ibid.; see also People v. Gutierrez (2009) 45 Cal.4th 789, 823.)