HotSpot在不同环境里的VM参数默认值参考
暂时就放个gist链接出来：>>
https://gist.github.com/827140 <<
多数参数的意义在这里可以查到： globals.hpp
Windows测试环境：
Linux x64测试环境：
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一些参数的备注：
PrintClassHistogramBeforeFullGC (>= 6u18)
UseFPUForSpilling在支持SSE2或异常的系统上默认仍然是false的，但打开AggressiveOpts则会变为true
UseOprofile 留意一下这个参数，默认是false
MaxTenuringThreshold在使用CMS时的默认值会变成4
====================================================================
参数相关讨论：
JVM调优的"标准参数"的各种陷阱
多数参数的意义在这里可以查到： globals.hpp
Windows测试环境：
OS: Windows XP Build 2600 Service Pack 3 CPU:total 2 (2 cores per cpu, 1 threads per core) family 6 model 23 stepping 10, cmov, cx8, fxsr, mmx, sse, sse2, sse3, ssse3, sse4.1 Memory: 4k page, physical 3405352k(2067228k free), swap 5334424k(3848208k free) vm_info: Java HotSpot(TM) Client VM (19.0-b09) for windows-x86 JRE (1.6.0_23-b05), built on Nov 12 2010 15:00:43 by "java_re" with MS VC++ 7.1 (VS2003)
OS: Windows XP Build 2600 Service Pack 3 CPU:total 2 (2 cores per cpu, 1 threads per core) family 6 model 23 stepping 10, cmov, cx8, fxsr, mmx, sse, sse2, sse3, ssse3, sse4.1 Memory: 4k page, physical 3405352k(2043728k free), swap 5334424k(3801564k free) vm_info: Java HotSpot(TM) Server VM (19.0-b09) for windows-x86 JRE (1.6.0_23-b05), built on Nov 12 2010 14:54:05 by "java_re" with MS VC++ 7.1 (VS2003)
Linux x64测试环境：
OS:Red Hat Enterprise Linux Server release 5.4 (Tikanga) uname:Linux 2.6.18-164.el5xen #1 SMP Tue Aug 18 15:59:52 EDT 2009 x86_64 libc:glibc 2.5 NPTL 2.5 rlimit: STACK 10240k, CORE 0k, NPROC 28064, NOFILE 1024, AS infinity load average:0.04 0.02 0.00 /proc/meminfo: MemTotal: 3584000 kB MemFree: 1742760 kB Buffers: 342260 kB Cached: 1122924 kB SwapCached: 2076 kB Active: 694568 kB Inactive: 905416 kB HighTotal: 0 kB HighFree: 0 kB LowTotal: 3584000 kB LowFree: 1742760 kB SwapTotal: 1052248 kB SwapFree: 1045628 kB Dirty: 20 kB Writeback: 0 kB AnonPages: 133980 kB Mapped: 17656 kB Slab: 144916 kB PageTables: 2540 kB NFS_Unstable: 0 kB Bounce: 0 kB CommitLimit: 2844248 kB Committed_AS: 268736 kB VmallocTotal: 34359738367 kB VmallocUsed: 700 kB VmallocChunk: 34359737667 kB CPU:total 4 (4 cores per cpu, 1 threads per core) family 6 model 15 stepping 11, cmov, cx8, fxsr, mmx, sse, sse2, sse3, ssse3 /proc/cpuinfo: processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 15 model name : Intel(R) Xeon(R) CPU E5320 @ 1.86GHz stepping : 11 cpu MHz : 1861.913 cache size : 4096 KB physical id : 0 siblings : 1 core id : 0 cpu cores : 1 fpu : yes fpu_exception : yes cpuid level : 10 wp : yes flags : fpu de tsc msr pae cx8 apic sep cmov pat clflush acpi mmx fxsr sse sse2 ss ht syscall nx lm constant_tsc pni cx16 lahf_lm bogomips : 4656.41 clflush size : 64 cache_alignment : 64 address sizes : 38 bits physical, 48 bits virtual power management: processor : 1 vendor_id : GenuineIntel cpu family : 6 model : 15 model name : Intel(R) Xeon(R) CPU E5320 @ 1.86GHz stepping : 11 cpu MHz : 1861.913 cache size : 4096 KB physical id : 1 siblings : 1 core id : 0 cpu cores : 1 fpu : yes fpu_exception : yes cpuid level : 10 wp : yes flags : fpu de tsc msr pae cx8 apic sep cmov pat clflush acpi mmx fxsr sse sse2 ss ht syscall nx lm constant_tsc pni cx16 lahf_lm bogomips : 4656.41 clflush size : 64 cache_alignment : 64 address sizes : 38 bits physical, 48 bits virtual power management: processor : 2 vendor_id : GenuineIntel cpu family : 6 model : 15 model name : Intel(R) Xeon(R) CPU E5320 @ 1.86GHz stepping : 11 cpu MHz : 1861.913 cache size : 4096 KB physical id : 2 siblings : 1 core id : 0 cpu cores : 1 fpu : yes fpu_exception : yes cpuid level : 10 wp : yes flags : fpu de tsc msr pae cx8 apic sep cmov pat clflush acpi mmx fxsr sse sse2 ss ht syscall nx lm constant_tsc pni cx16 lahf_lm bogomips : 4656.41 clflush size : 64 cache_alignment : 64 address sizes : 38 bits physical, 48 bits virtual power management: processor : 3 vendor_id : GenuineIntel cpu family : 6 model : 15 model name : Intel(R) Xeon(R) CPU E5320 @ 1.86GHz stepping : 11 cpu MHz : 1861.913 cache size : 4096 KB physical id : 3 siblings : 1 core id : 0 cpu cores : 1 fpu : yes fpu_exception : yes cpuid level : 10 wp : yes flags : fpu de tsc msr pae cx8 apic sep cmov pat clflush acpi mmx fxsr sse sse2 ss ht syscall nx lm constant_tsc pni cx16 lahf_lm bogomips : 4656.41 clflush size : 64 cache_alignment : 64 address sizes : 38 bits physical, 48 bits virtual power management: Memory: 4k page, physical 3584000k(1742760k free), swap 1052248k(1045628k free) vm_info: Java HotSpot(TM) 64-Bit Server VM (20.0-b08) for linux-amd64 JRE (1.6.0_25-ea-b01), built on Jan 27 2011 13:11:34 by "java_re" with gcc 3.2.2 (SuSE Linux)
====================================================================
一些参数的备注：
PrintClassHistogramBeforeFullGC (>= 6u18)
UseFPUForSpilling在支持SSE2或异常的系统上默认仍然是false的，但打开AggressiveOpts则会变为true
UseOprofile 留意一下这个参数，默认是false
MaxTenuringThreshold在使用CMS时的默认值会变成4
====================================================================
参数相关讨论：
JVM调优的"标准参数"的各种陷阱