Rewriting byte codes

[Artur Biesiadowski]

Erik Corry wrote:

>>AFAIK, hotspot stops thread, replaces closest safe points with some trap 
>>and let thread run until it hit one. Then it restores original 
>>instruction and voila.
> 
> 
> This sounds pretty ugly to me, since it involves lots of writing
> to the instruction stream with corresponding I-cache flushes etc.

I think that I-cache flush penalty is neglible compared to cost of 
switching threads few times and performing gc. We are talking about 
extra 20-50 cycles and gc will take about 1ms minimum (which gives about 
1000000 cycles).

Artur