public void onTick(Instrument instrument, ITick tick) throws JFException {
console.getOut().println("sssssssssssssssssssssssssssssssss3333333333333");
double[] rsi = indicators.rsi(instrument, Period.FOUR_HOURS, OfferSide.BID, IIndicators.AppliedPrice.CLOSE, 14,Filter.ALL_FLATS,0, tick.getTime(),1);
console.getOut().println("rsi: "+ rsi[0]);
}

Are you sure that the slowdown is due to the RSI compilation? We tested the performance of the following strategy in Historical Tester and the calculation times normally were below on millisecond:

    @Override
    public void onTick(Instrument instrument, ITick tick) throws JFException {
        long start = System.nanoTime();
        double[] RSIArray = indicators.rsi(instrument, period, side, appliedPrice, 14, Filter.WEEKENDS, 1, tick.getTime(), 0);
        long t1 = System.nanoTime();
        console.getOut().format("now=%s tick time=%s calculated in %.6f secs, value=%.5f", 
                DateUtils.format(System.currentTimeMillis()), 
                DateUtils.format(tick.getTime()), 
                ((double)t1 - start) * Math.pow(10, -9),
                RSIArray[0]
        ).println();
    }

For subsequent requests please provide a full example strategy which replicates the case and a screenshot of your Historical Tester settings.

YES .It's this fragment code.history tester went very slowly。。
I download your file .and run normly.but my fragment code run very slowly..
you can copy that to your file ,and have a try.

hello support,I found the diffirent.just in
double[] rsi = indicators.rsi(instrument, Period.FOUR_HOURS, OfferSide.BID, IIndicators.AppliedPrice.CLOSE, 14,Filter.ALL_FLATS,0, tick.getTime(),1); changed to

double[] rsi = indicators.rsi(instrument, Period.FOUR_HOURS, OfferSide.BID, IIndicators.AppliedPrice.CLOSE, 14,Filter.ALL_FLATS,1, tick.getTime(),0);
it became very faster.
but I did not know the real reason? and I want to use the newly tick's rsi value. what to do?

The javadoc regarding the last parameter in question:
numberOfCandlesAfter - how much candles to load after (and not including) the candle with time specified in the time parameter

The time parameter is tick.getTime(), which actually the latest tick. So there are no ticks or candles after this tick. Maybe there are some issues (slowdowns) when you want to calculate something for a bar that does not exists? Support must clarify (on Monday )

More on indicator calculation on general here.
And the javadoc, where you can find information about functions: https://www.dukascopy.com/client/javadoc/

You are trying to calculate on the candle that does not exist yet - the one after the currently forming candle. It is rather an API discrepancy that a JFException does not get thrown (we are going to take a look at this).
Our example does just that - it calculates the RSI value on the current candle. You can make sure of this by plotting an RSI indicator on the same feed chart, a convenient way how to do this can be found here:
https://www.dukascopy.com/wiki/#Add_indicators_on_chart/Include_in_OHLC

yes。thankyou
But throw an exceoption rather than a very slowly run