Code review request: CR 6995781 Native Memory Tracking Phase 1

[Zhengyu Gu]

Oops, the links still wrong, try again:

http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6995781

http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7151532

Thanks,

-Zhengyu

On 6/12/2012 2:50 PM, Zhengyu Gu wrote:
> Sorry, the public CRs are:
>
> http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=6995781 
> <http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7170449>
> http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7151532 
> <http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7170449>
>
> Thanks,
>
> -Zhengyu
>
> On 6/12/2012 12:11 PM, Zhengyu Gu wrote:
>> This is the webrev for native memory tracking phase 1, which is 
>> tracked by CR6995781 
>> (http://monaco.us.oracle.com/detail.jsf?cr=6995781) and related DCmd 
>> CR7151532 (http://monaco.us.oracle.com/detail.jsf?cr=7151532).
>>
>> Native memory tracking (NMT) phase 1, is designed to track native 
>> memory (malloc'd and mmap'd) usages by VM code only, it does not 
>> track the memory usages by libraries and JNI code.
>>
>> On the implementation side, NMT intercepts memory related calls in os 
>> implementation, such as os::malloc, os::realloc, os::free, 
>> os::reserve_memory, os::commit_memory and etc. the caller is required 
>> to provide the 'memory type' information, which represents the VM 
>> subsystem that the memory is allocated for. The 'memory type' is 
>> defined in /src/share/memory/allocation.hpp. Also, a caller's pc is 
>> captured if NMT tracking level is set to detail.
>>
>> There are a few ways to tag a memory block to a memory type:
>>
>> 1. os::malloc takes an extra parameter for the memory type.
>> 2. CHeapObj now is a template, it takes a memory type as template 
>> parameter to tag the object to a specified memory type.
>> 3. Utility classes, such as Arena, GrowableArray and etc. the memory 
>> type is a parameter of 'new' operator.
>> 4. Virtual memory block is tagged on its base address.
>>
>> When NMT intercepts the call, a memory record is created and 
>> serialized by a sequence number, generated by global sequence 
>> generator. The memory record is written to a per-thread recorder 
>> without a  lock, when calling thread is a 'safepoint visible' 
>> JavaThread - a JavaThread that will block at safepoint. Otherwise, 
>> ThreadCritical lock is acquired to write to a global recorder. The 
>> recorders (or raw data) are synchronized at some safepoints, and 
>> global sequence generator is also reset at synchronization time, to 
>> avoid overflow the sequence number.
>>
>> A dedicated NMT worker thread is created to process the raw memory 
>> records. It first stages a generation of raw data (a generation is 
>> defined as span between resets of global sequence number), then 
>> promotes the staged data to a global snapshot, which maintains 
>> information of all 'live' memory block.
>>
>> NMT Tracking option has to be specified through VM command line 
>> option -XX:NativeMemoryTracking (off by default), tracking level can 
>> not be altered during runtime, but it can be shutdown through jcmd tool.
>>
>> NMT DCmd implements a set of sub-command to control NMT runtime and 
>> request tracking data.
>>
>> Webrev: http://cr.openjdk.java.net/~zgu/6995781/webrev.00
>>
>> The tests and results:
>>
>>  - Passed internal smoke tests
>>  - JTreg test: http://cr.openjdk.java.net/~zgu/6995781/JTreport/
>>
>>
>> Additional notes:
>>   - Some classes' new operators are marked _NOINLINE_ (for the same 
>> purpose as above), the performance runs, I performed, indicate that 
>> they do not impact performance numbers.
>>
>>   - SA agent changes are in progress
>>
>> Thanks,
>>
>> -Zhengyu
>>
>>
>>
>>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mail.openjdk.java.net/pipermail/hotspot-dev/attachments/20120612/1365c48c/attachment.html