Pauses for GC are per-actor for the Erlang VM, so indeed no stop-the-world, or if there is, it's a very low latency sync point where the GC to switches mode.
There are plenty of soft and hard real-time GCs though suitable for use with any GC'd language. For instance, the CHICKEN collector in [1] is an absurdly simple copying collector with an observed maximum pause time of 120 microseconds with average pauses of 1 microsecond.
Low-latency GC tends to sacrifice a little throughput though, which is why it's not more widely used. Relative to a standard concurrent MS, CHICKEN adds up to 30% in execution time, although the average seems to hover around 10-15%.
There are plenty of soft and hard real-time GCs though suitable for use with any GC'd language. For instance, the CHICKEN collector in [1] is an absurdly simple copying collector with an observed maximum pause time of 120 microseconds with average pauses of 1 microsecond.
Low-latency GC tends to sacrifice a little throughput though, which is why it's not more widely used. Relative to a standard concurrent MS, CHICKEN adds up to 30% in execution time, although the average seems to hover around 10-15%.
[1] ftp://ftp.inf.ufrgs.br/pub/geyer/PDP-Pos/Artigos/PDP-2011-2-TL1-artigos/PDP-2011-2-TL1-GT-A%20Study%20of%20Concurrent%20Real-Time%20Garbage%20Collectors.pdf