Bad perfomance on drawing markers into a linechart


I have some plots that update their data in an interval (e.g. every 10 seconds). While I hover over the plot and the interval is triggered I observed that the plot is freezing for some seconds. After I analyse this topic it seems, that the markers are the problem.

I reproduce a example for jsFiddle:
Here you see in the console of the browser, that a redraw without markers needs 50-100 ms and a redraw WITH markers needs 2000 ms…
So it needs in minimum the tenfold of time. Anyone now why this appears and maybe a workaround for that?