服务器评测
1.错误案例
- www.linuxidc.com@Ubuntu:~/Downloads$ jmap -heap 3991
- Attaching to process ID 3991, please wait…
- Error attaching to process: sun.jvm.hotspot.debugger.DebuggerException: Can’t attach to the process
2.解决方案
1）修改/etc/sysctl.d/10-ptrace.conf文件如下：
< kernel.yama.ptrace_scope = 1 — > kernel.yama.ptrace_scope = 0（即将1改成0）
2）重启
3.成功
- www.linuxidc.com@ubuntu:~$ jmap -heap 1835
- Attaching to process ID 1835, please wait…
- Debugger attached successfully.
- Client compiler detected.
- JVM version is 20.0-b11
- using thread-local object allocation.
- Mark Sweep Compact GC
- Heap Configuration:
- MinHeapFreeRatio = 40
- MaxHeapFreeRatio = 70
- MaxHeapSize = 402653184 (384.0MB)
- NewSize = 1048576 (1.0MB)
- MaxNewSize = 4294901760 (4095.9375MB)
- OldSize = 4194304 (4.0MB)
- NewRatio = 2
- SurvivorRatio = 8
- PermSize = 12582912 (12.0MB)
- MaxPermSize = 268435456 (256.0MB)
- Heap Usage:
- New Generation (Eden + 1 Survivor Space):
- capacity = 13697024 (13.0625MB)
- used = 6592008 (6.286628723144531MB)
- free = 7105016 (6.775871276855469MB)
- 48.12730122981459% used
- Eden Space:
- capacity = 12189696 (11.625MB)
- used = 6592008 (6.286628723144531MB)
- free = 5597688 (5.338371276855469MB)
- 54.07852665070565% used
- From Space:
- capacity = 1507328 (1.4375MB)
- used = 0 (0.0MB)
- free = 1507328 (1.4375MB)
- 0.0% used
- To Space:
- capacity = 1507328 (1.4375MB)
- used = 0 (0.0MB)
- free = 1507328 (1.4375MB)
- 0.0% used
- tenured generation:
- capacity = 30273536 (28.87109375MB)
- used = 18162752 (17.32135009765625MB)
- free = 12110784 (11.54974365234375MB)
- 59.995475916655394% used
- Perm Generation:
- capacity = 38273024 (36.5MB)
- used = 38107752 (36.342384338378906MB)
- free = 165272 (0.15761566162109375MB)
- 99.56817626953125% used
