"perProc":    trace.UtilPerProc,
	"stw":        trace.UtilSTW,
	"background": trace.UtilBackground,
	"assist":     trace.UtilAssist,
	"sweep":      trace.UtilSweep,
}

func requestUtilFlags(r *http.Request) trace.UtilFlags {
	var flags trace.UtilFlags
	for _, flagStr := range strings.Split(r.FormValue("flags"), "|") {
		flags |= utilFlagNames[flagStr]
	}
	return flags
}