Garbage collector configuration
PyPy's default minimark garbage collector is configurable through several environment variables:
- The nursery size. Defaults to 4MB. Small values (like 1 or 1KB) are useful for debugging.
- Major collection memory factor. Default is 1.82, which means trigger a major collection when the memory consumed equals 1.82 times the memory really used at the end of the previous major collection.
- Major collection threshold's max growth rate. Default is 1.4. Useful to collect more often than normally on sudden memory growth, e.g. when there is a temporary peak in memory usage.
- The max heap size. If coming near this limit, it will first collect more often, then raise an RPython MemoryError, and if that is not enough, crash the program with a fatal error. Try values like 1.6GB.
- The major collection threshold will never be set to more than PYPY_GC_MAX_DELTA the amount really used after a collection. Defaults to 1/8th of the total RAM size (which is constrained to be at most 2/3/4GB on 32-bit systems). Try values like 200MB.
- Don't collect while the memory size is below this limit. Useful to avoid spending all the time in the GC in very small programs. Defaults to 8 times the nursery.
- Enable extra checks around collections that are too slow for normal use. Values are 0 (off), 1 (on major collections) or 2 (also on minor collections).