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1.122.5 ObjectMemory: accessing

allocFailures
Answer the number of times that the old-space allocator found no block that was at least as big as requested, and had to ask the operating system for more memory.


allocMatches
Answer the number of times that the old-space allocator found a block that was exactly as big as requested.


allocProbes
Answer the number of free blocks that the old-space allocator had to examine so far to allocate all the objects that are in old-space


allocSplits
Answer the number of times that the old-space allocator could not find a block that was exactly as big as requested, and had to split a larger free block in two parts.


bytesPerOOP
Answer the number of bytes that is taken by an ordinary object pointer (in practice, a field such as a named instance variable).


bytesPerOTE
Answer the number of bytes that is taken by an object table entry (in practice, the overhead incurred by every object in the system, with the sole exception of SmallIntegers).


edenSize
Answer the number of bytes in the `eden' area of the young generation (in practice, the number of allocated bytes between two scavenges).


edenUsedBytes
Answer the number of bytes that are currently filled in the `eden' area of the young generation.


fixedSpaceSize
Answer the number of bytes in the special heap devoted to objects that the garbage collector cannot move around in memory.


fixedSpaceUsedBytes
Answer the number of bytes that are currently filled in the special heap devoted to objects that the garbage collector cannot move around in memory.


numCompactions
Answer the number of oldspace compactions that happened since the VM was started.


numFixedOOPs
Answer the number of objects that the garbage collector cannot move around in memory.


numFreeOTEs
Answer the number of entries that are currently free in the object table.


numGlobalGCs
Answer the number of global garbage collections (collection of the entire heap) that happened since the VM was started.


numGrowths
Answer the number of times that oldspace was grown since the VM was started.


numOTEs
Answer the number of entries that are currently allocated for the object table.


numOldOOPs
Answer the number of objects that reside in the old generation.


numScavenges
Answer the number of scavenges (fast collections of the young generation) that happened since the VM was started.


numWeakOOPs
Answer the number of weak objects that the garbage collector is currently tracking.


oldSpaceSize
Answer the number of bytes in the old generation.


oldSpaceUsedBytes
Answer the number of bytes that are currently filled in the old generation.


reclaimedBytesPerGlobalGC
Answer the average number of bytes that are found to be garbage during a global garbage collections.


reclaimedBytesPerScavenge
Answer the average number of bytes that are found to be garbage during a scavenge.


reclaimedPercentPerScavenge
Answer the average percentage of allocated bytes that are found to be garbage during a scavenge. If this number falls below 60-70 you should definitely increment the size of the eden, because you risk that scavenging is eating a considerable fraction of your execution time; do the measurement on a restarted image, so that the extra tenuring incurred when creating long-lived objects such as classes or methods is not considered.


survSpaceSize
Answer the number of bytes in the `survivor' area of the young generation (the area to which young objects are relocated during scavenges).


survSpaceUsedBytes
Answer the number of bytes that are currently filled in the `survivor' area of the young generation.


tenuredBytesPerScavenge
Answer the average number of bytes that are promoted to oldspace during a scavenge.


timeBetweenGlobalGCs
Answer the average number of milliseconds between two global garbage collections.


timeBetweenGrowths
Answer the average number of milliseconds between decisions to grow the heap.


timeBetweenScavenges
Answer the average number of milliseconds between two scavenges (fast collections of the young generation).


timeToCollect
Answer the average number of milliseconds that a global garbage collection takes.


timeToCompact
Answer the average number of milliseconds that compacting the heap takes. This the same time that is taken by growing the heap.


timeToScavenge
Answer the average number of milliseconds that a scavenge takes (fast collections of the young generation).