Command format jstat Command command format: jstat [Options] vmid [interval] [count]
Parameter description: Options, option, we generally use-gcutil to view GC conditions
The VMID,VM process number, which is the currently running Java process number
Interval, interval, units of seconds or milliseconds
Count, number of prints, print countless times if default
Examples of the example that are typically run commands are as follows: JSTAT-GC 12538 5000
That is, every 5 seconds, the process number 12538 is displayed in the Java into the GC case, display content such as:
The description of the results shows the following (some of the results are shown by other parameters, not described): s0c: The capacity of the first Survivor (Survivor area) in the Young Generation (bytes)
S1C: Capacity of the second survivor (Survivor area) in the younger generation (bytes)
S0U: The first survivor (Survivor area) of the young generation has currently used space (bytes)
S1U: The second survivor (Survivor area) of the young generation has currently used space (bytes)
EC: The Capacity of Eden (Eden) in the Young Generation (bytes)
EU: Eden (Eden) in the young generation has currently used space (bytes)
Capacity of the Oc:old generation (bytes)
Ou:old currently used space (bytes)
Pc:perm (persistent generation) capacity (bytes)
Pu:perm (persistent generation) currently used space (bytes)
YGC: Number of GC times in young generations from application startup to sampling
YGCT: The time taken by the GC in the young generation from application startup to sampling (s)
FGC: Old (full GC) GC count from application boot to sampling
FGCT: Time taken from an old (full GC) GC when the application boots to sampling (s)
GCT: GC Total time from Application boot to sample (s)
NGCMN: initial (minimum) size in Young generation (bytes)
NGCMX: Max capacity of young generation (bytes)
NGC: Current capacity in young generation (bytes)
The size (in bytes) of the initialization (minimum) in ogcmn:old generation
Maximum capacity of the Ogcmx:old generation (bytes)
The current newly generated capacity of the Ogc:old generation (bytes)
The size (in bytes) of the initialization (minimum) in pgcmn:perm generation
Maximum capacity of the Pgcmx:perm generation (bytes)
The current newly generated capacity of the Pgc:perm generation (bytes)
S0: The first survivor (Survivor area) of the young generation has been used as a percentage of current capacity
S1: The second survivor (Survivor area) in the younger generation has been used as a percentage of current capacity
E: Eden (Eden) in the young generation has been used as a percentage of current capacity
Percentage of current capacity used by O:old generation
Percentage of current capacity used by P:perm generation
S0CMX: Maximum Capacity (bytes) of the first Survivor (Survivor area) in the young generation
S1CMX: Maximum capacity of the second survivor (Survivor area) in the younger generation (bytes)
ECMX: Maximum capacity of Eden (Eden) in the Young Generation (bytes)
DSS: Capacity (bytes) currently required for Survivor (surviving area) (Eden area Full)
TT: Limited number of holds
MTT: Maximum number of hold limit
Linux uses the Jstat command to view the GC status of the JVM
