Linas Vepstas <linasveps...@gmail.com>: > which suggests that the vast majority of time is spent in GC, and not > in either scheme/guile, or my wrapped c++ code.
That may well be normal. > 4 gc's/minute means one every 15 seconds, which sounds reasonable, > except that RAM usage is so huge, that each GC takes many seconds to > complete. That may or may not be normal. However, it should not be a function of how much RAM has been allocated ourside Guile's heap. > Anyway, this demo gives a scenario where gc seems to run too often. How often is too often? I would imagine the objective is to minimize the stop-the-world periods. IOW, you usually want the program to run very steadily. > I have other scenarios where it does not run often enough -- I have > one where the working set is about 200MBytes, but guile happily grows > to 10GB or 20GB RAM over a few hours. You mean the size of Guile's heap? That seems pathological. Maybe there are lots of values in your data that accidentally look like heap addresses. > My solution for that other case is to manually GC whenever gc-stats > gets above 1GB, because I know a priori my working set is smaller than > that. > > The overall message seems to be that gc either runs too often, or not > often enough. Some sort of better planning is needed. > > I'm motivated to explore this, as it actually impacts my work. Absolutely, although as an application programmer you should be able to trust that GC just works. Marko
