RFR: 8246135: ZGC: Save important log lines and print them when dumping hs_err files

[Stefan Karlsson]

Thanks.

StefanK

On 2020-06-02 10:47, stefan.johansson at oracle.com wrote:
> Still good,
> Stefan
>
> On 2020-06-02 09:55, Stefan Karlsson wrote:
>> Found one more line that we should save:
>>   https://cr.openjdk.java.net/~stefank/8246135/webrev.03.delta/
>>   https://cr.openjdk.java.net/~stefank/8246135/webrev.03/
>>
>> StefanK
>>
>> On 2020-06-02 08:09, Stefan Karlsson wrote:
>>> Thanks for reviewing.
>>>
>>> StefanK
>>>
>>> On 2020-06-01 20:50, stefan.johansson at oracle.com wrote:
>>>> Hi Stefan,
>>>>
>>>> On 2020-06-01 16:38, Stefan Karlsson wrote:
>>>>> Updated webrev:
>>>>> https://cr.openjdk.java.net/~stefank/8246135/webrev.02
>>>> Looks good, thanks for making the functionality shared. Filed 
>>>> https://bugs.openjdk.java.net/browse/JDK-8246272 for the other GCs.
>>>>
>>>> Cheers,
>>>> Stefan
>>>>
>>>>>
>>>>> StefanJ asked if I could make this a utility that other GCs could 
>>>>> use as well. I've moved the functionality to 
>>>>> gc/shared/gcLogPrecious.[hc]pp, but I haven't implemented this for 
>>>>> the other GCs. That part is left for separate RFEs.
>>>>>
>>>>> Thanks,
>>>>> StefanK
>>>>>
>>>>> On 2020-05-29 12:23, Stefan Karlsson wrote:
>>>>>> Hi all,
>>>>>>
>>>>>> Please review this patch to save some of the important ZGC log 
>>>>>> lines and print them when dumping hs_err files.
>>>>>>
>>>>>> https://cr.openjdk.java.net/~stefank/8246135/webrev.01/
>>>>>> https://bugs.openjdk.java.net/browse/JDK-8246135
>>>>>>
>>>>>> The patch adds a concept of "precious" log lines. What's 
>>>>>> typically logged are GC initialization lines, but also error 
>>>>>> messages are saved. These lines are then dumped in the hs_err 
>>>>>> file if the JVM crashes or hits an assert. The lines can also be 
>>>>>> printed in a debugger to get a quick overview when debugging.
>>>>>>
>>>>>> The precious lines are always saved, but just like any other 
>>>>>> Unified Logging calls, only logged if the tags are enabled.
>>>>>>
>>>>>> The patch builds on the JDK-8246134 patch. The hs_err output 
>>>>>> looks like this:
>>>>>>
>>>>>> ZGC Precious Log:
>>>>>>  NUMA Support: Disabled
>>>>>>  CPUs: 8 total, 8 available
>>>>>>  Memory: 16384M
>>>>>>  Large Page Support: Disabled
>>>>>>  Medium Page Size: 32M
>>>>>>  Workers: 5 parallel, 1 concurrent
>>>>>>  Address Space Type: Contiguous/Unrestricted/Complete
>>>>>>  Address Space Size: 65536M x 3 = 196608M
>>>>>>  Min Capacity: 42M
>>>>>>  Initial Capacity: 256M
>>>>>>  Max Capacity: 4096M
>>>>>>  Max Reserve: 42M
>>>>>>  Pre-touch: Disabled
>>>>>>  Uncommit: Enabled
>>>>>>  Uncommit Delay: 300s
>>>>>>  Runtime Workers: 5 parallel
>>>>>>
>>>>>> ZGC Globals:
>>>>>>  GlobalPhase:       2 (Relocate)
>>>>>>  GlobalSeqNum:      1
>>>>>>  Offset Max:        4096G (0x0000040000000000)
>>>>>>  Page Size Small:   2M
>>>>>>  Page Size Medium:  32M
>>>>>>
>>>>>> ZGC Metadata Bits:
>>>>>>  Good:              0x0000100000000000
>>>>>>  Bad:               0x00002c0000000000
>>>>>>  WeakBad:           0x00000c0000000000
>>>>>>  Marked:            0x0000040000000000
>>>>>>  Remapped:          0x0000100000000000
>>>>>>
>>>>>> Heap:
>>>>>>  ZHeap           used 12M, capacity 256M, max capacity 4096M
>>>>>>  Metaspace       used 6501K, capacity 6615K, committed 6784K, 
>>>>>> reserved 1056768K
>>>>>>   class space    used 559K, capacity 588K, committed 640K, 
>>>>>> reserved 1048576K
>>>>>>
>>>>>> ZGC Page Table:
>>>>>>  Small   0x0000000000000000 0x0000000000200000 0x0000000000200000 
>>>>>> Allocating
>>>>>>  Small   0x0000000000200000 0x0000000000240000 0x0000000000400000 
>>>>>> Allocating
>>>>>>  Small   0x0000000000400000 0x0000000000600000 0x0000000000600000 
>>>>>> Allocating
>>>>>>  Small   0x0000000000600000 0x0000000000800000 0x0000000000800000 
>>>>>> Allocating
>>>>>>  Small   0x0000000000800000 0x00000000009c0000 0x0000000000a00000 
>>>>>> Allocating
>>>>>>  Small   0x0000000000a00000 0x0000000000a40000 0x0000000000c00000 
>>>>>> Allocating
>>>>>>
>>>>>> Thanks,
>>>>>> StefanK
>>>>>
>>>
>>