Memory and CPU
What is the heap size of my java application
$ java -XX:+PrintFlagsFinal -version | grep HeapSize
uintx ErgoHeapSizeLimit = 0 {product}
uintx HeapSizePerGCThread = 87241520 {product}
uintx InitialHeapSize := 190840832 {product}
uintx LargePageHeapSizeThreshold = 134217728 {product}
uintx MaxHeapSize := 3040870400 {product}
java version "1.8.0_92"
Java(TM) SE Runtime Environment (build 1.8.0_92-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.92-b14, mixed mod
Native memory tracking
jcmd 1 VM.native_memory summary
Parameters of a running JVM
You can use jps
1
jps -lvm
Default heap size
On a Unix/Linux system, you can do 2
java -XX:+PrintFlagsFinal -version | grep HeapSize
How much memory does my machine have
The best way to find out RAM information such as amount of free and used memory in the system is to open a terminal and type the following command3
$ free -m
total used free shared buff/cache available
Mem: 11598 10364 188 634 1044 339
Swap: 0 0
How many cpus does my machine have
$ cat /proc/cpuinfo | grep processor | wc -l
8
1. Getting the parameters of a running JVM, by Peter Lawrey (15 Mar, 2011) stackoverflow ↩
2. How is the default Java heap size determined?, by stones333 (14 Dec, 2012) stackoverflow ↩
3. How Much RAM does my Ubuntu / Fedora Linux desktop PC have?, (25 Apr, 2007) nixCraft ↩
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