HPjmeter 4.3 User's Guide

Table 10 Fields Captured in GC Log Data When Using -Xverbosegc print options (continued)

• When %1 is equal to 5, %2 the G1 sub-type and whether there was a G1 initial mark. The form for this data

set is given as n.m where n indicates young or mixed GC, as follows:

◦ 0: young GC

◦ 1: mixed GC

and m indicates whether it contains initial-mark, as follows:

◦ 0: no initial-mark

◦ 1: contains initial-mark

◦

• When %1 is equal to 6%2 indicates that a complete background G1 concurrent mark cycle has occurred.

Reasons for the GC are given as:

◦ 1: Occupancy > InitiatingHeapOccupancy

◦ 2: GCLocker and option GCLockerInvokesConcurrentis true

◦ 3: Explicit gc and option ExplicitGCInvokesConcurrent is true

◦ 4: G1 humongous allocation caused concurrent mark cycle

◦ When %1 is equal to 7, %2 indicates that an incomplete background, garbage first concurrent mark cycle

has occurred. The form for this data set is given as n.m where n is the GC reason as follows:

– 1: Occupancy > InitiatingHeapOccupancy

– 2: GCLocker and option GCLockerInvokesConcurrent is true

– 3: Explicit gc and ExplicitGCInvokesConcurrent is true

– 4: G1 humongous allocation caused concurrent mark cycle

and m indicates the background G1 state when yielding, as follows:

◦ 0: Idling

◦ 1: RootScanning

◦ 2: Marking

◦ 3: Remarking

◦ 4: Cleanup

◦

• When %1 is equal to 11, %2 indicates the stop-the-world phase of CMS GC, as follows:

◦ 2: Initial marking (first stop-the-world phase)

◦ 4: Final marking (second stop–the-world phase)

• When %1 is equal to 12, %2 indicates the stop-the-world phase of G1 GC, as follows:

◦ 3: Remarking (first stop-the-world phase)

◦ 4: Cleanup (second stop–the-world phase)

Program time at the beginning of the collection, in seconds%3

Garbage collection invocation. Counts of background CMS garbage collections and other garbage collections

are maintained separately

Size of the object allocation request that forced the GC, in bytes%5

Obtaining Garbage Collection Data 97