python garbage collection example

similar to recovering objects in the Java heap. Take the collection of literals in a constant pool as an example, for example, a string "ABC" has entered a constant pool, but the current system does not have any string object called "abc", in other words, there is no string object referencing the "ABC" constant in the constant pool, There is no other reference t

importantly, the circular reference cannot be deleted (for example, two objects are referenced to each other ). Other methods involve the concept of root set. In short, it refers to the object reference in the stack and the set of objects in the heap. From these objects, we can trace all live objects at the first level. "Any object referred to by a root is reachable and is therefore a live object. additionally, any objects referred to by a live obje

GC Optimization Options Options Description -xms Initial heap Memory size -xmx Maximum heap memory size -xmn The size of the young generation -xx:permsize The size of the initial permanent generation -xx:maxpermsize The largest permanent generation of the size Example Usage of the JVM GC Optionsjava -X

1. PrefaceGarbage collector is the previous chapter of the garbage collection algorithm theoretical knowledge of the specific implementation of the different virtual machines provided by the garbage collector may be a great difference, and we must explain in advance that there is no best garbage collector, more than a

Java's garbage collection has a variety of strategies, and the default policy is often changed.-for example, serial, parallel, CMS; How about the concrete to Minor, old? Command java-xx:+printflagsfinal-version, providing help: BOOL USEPARNEWGC false {product} bool USEPARALLELGC

objects are neither static variables nor local variables, instead, all allocated memory blocks in the heap. Reference Counting AlgorithmBefore 1960, when people designed a garbage collection mechanism for The LISP Language in the embryo, the first algorithm that came to mind was to reference the counting algorithm. Taking napkin as an example, the principle of

space they occupy will be reclaimed for allocation to new objects. To understand the garbage collection mechanism and the various garbage collection algorithms, you first need to know some knowledge about the Java Platform memory model. Garbage

Purge and reference count. Reference counts are less common, and tag cleanup is more commonly used.Second, Mark ClearThe most common way of garbage collection in JS is to mark clear. When a variable enters the environment, for example, when a variable is declared in a function, the variable is marked as "going into the environment." Logically, it is never possib

for garbage collection, and the other is used for user threads. In this case, there were two CPUs running user threads. Now there is one thread, and the efficiency will drop sharply. That is to say, the throughput is reduced (that is, the CPU usage is reduced ). Concurrent cleanup: In this process, the generated garbage cannot be cleared (because it occurs afte

attribute to obtain the highest algebra of GC. Currently, the highest generation is set value 2. You can call the GC. Collect () method to force the Garbage Collector to perform garbage collection. The collect method has two reloads: Void GC. Collect (int32 generation) void GC. Collect () The first method allows you to specify the generation to be recycled.

The current commercial virtual machine garbage collection uses the "generational collection" algorithm, that is, according to the different life cycle of the object, divided into several pieces of memory, generally for the Cenozoic and the old era, different generations according to its characteristics of the use of the most appropriate

the entire managed heap. The method without parameters calls GC. Collect (GC. MaxGeneration) is equivalent to the whole collection. In general, the GC. Collect method should not be called; it is best to let the Garbage Collector determine when to call the Collect method according to its own algorithm. Even so, if you are more confident that you know when to do garbage