RFR(S) 8233826 Change CDS dumping tty->print_cr() to unified logging
coleen.phillimore at oracle.com
coleen.phillimore at oracle.com
Thu Dec 19 19:38:01 UTC 2019
On 12/19/19 2:08 PM, Ioi Lam wrote:
> Hi Jiangli & Coleen,
>
> Thanks for the comments. I agree with both of you that the -Xlog:cds
> "info"
> output is too verbose, so I moved the ones you suggested into the
> "debug" log.
>
> Coleen, I used -Xlog:cds=debug instead of -Xlog:cds+regions=info,
> because there's
> no current log of the cds+regions combination. My experience with have
> a minor
> combination like that is people (including me) will forget about it, and
> will end up using -Xlog:cds*=info, which produces too much output.
>
> Here's the update from the last webrev:
>
> http://cr.openjdk.java.net/~iklam/jdk15/8233826-cds-change-tty-to-ul.v02.delta/
>
>
> Sample output:
>
> java -Xshare:dump -Xlog:cds
> http://cr.openjdk.java.net/~iklam/jdk15/8233826-cds-change-tty-to-ul.v02.delta/log_cds.txt
>
I like this new output, especially that it ends with this, which is all
I care about generally.
[1.672s][info][cds] Dumping shared data to file:
[1.672s][info][cds] /jdk2/bld/dre-fastdebug/images/jdk/lib/server/classes.jsa
>
> java -Xshare:dump -Xlog:cds=debug
> http://cr.openjdk.java.net/~iklam/jdk15/8233826-cds-change-tty-to-ul.v02.delta/log_cds_debug.txt
>
>
This looks good to me.
Coleen
> Thanks
> - Ioi
>
>
> On 12/19/2019 9:01 AM, coleen.phillimore at oracle.com wrote:
>>
>> Hi Jiangli,
>>
>> On 12/18/19 7:34 PM, Jiangli Zhou wrote:
>>> Hi Coleen,
>>>
>>> On Wed, Dec 18, 2019 at 1:45 PM <coleen.phillimore at oracle.com> wrote:
>>>>
>>>>
>>>> On 12/18/19 12:35 PM, Jiangli Zhou wrote:
>>>>> On Wed, Dec 18, 2019 at 9:09 AM Ioi Lam <ioi.lam at oracle.com> wrote:
>>>>>> On 12/18/19 7:49 AM, Jiangli Zhou wrote:
>>>>>>> The default dumping output provides useful information,
>>>>>>> particularly
>>>>>>> with static archiving.
>>>>>> Hi Jiangli,
>>>>>>
>>>>>> Thanks for looking this patch.
>>>>>>
>>>>>> This patch affects only "informational" messages. It doesn't
>>>>>> affect the
>>>>>> warning/error messages, which I think are the ones that users
>>>>>> want to see.
>>>>>>
>>>>>> I agree that the informational messages are useful for developers
>>>>>> of CDS
>>>>>> (I look at them all the time). However, I don't know if any of the
>>>>>> following messages would be useful to a user of CDS. These
>>>>>> messages are
>>>>>> not printed during dynamic dumping, and no one has complained.
>>>>>>
>>>>> The number of archived classes and arrays, the size of the archive
>>>>> and
>>>>> etc are all useful information for users of static CDS dumping. If
>>>>> there is any failure, the output also provides helpful information
>>>>> for
>>>>> isolating when failure occurs.
>>>>>
>>>>>> $ java -Xshare:dump
>>>>>> Allocated shared space: 3221225472 bytes at 0x0000000800000000
>>>>>> Loading classes to share ...
>>>>>> Loading classes to share: done.
>>>>>> Reading extra data: done.
>>>>>> Rewriting and linking classes ...
>>>>>> Rewriting and linking classes: done
>>>>>> Number of classes 1258
>>>>>> instance classes = 1192
>>>>>> obj array classes = 58
>>>>>> type array classes = 8
>>>>>> Updating ConstMethods ... done.
>>>>>> Removing unshareable information ... done.
>>>>>> Scanning all metaspace objects ...
>>>>>> Allocating RW objects ...
>>>>>> Allocating RO objects ...
>>>>>> Relocating embedded pointers ...
>>>>>> Relocating external roots ...
>>>>>> Dumping symbol table ...
>>>>>> Dumping objects to closed archive heap region ...
>>>>>> Dumping objects to open archive heap region ...
>>>>>> Relocating SystemDictionary::_well_known_klasses[] ...
>>>>>> Removing java_mirror ... done.
>>>>>> mc space: 8728 [ 0.1% of total] out of 12288 bytes [
>>>>>> 71.0%
>>>>>> used] at 0x0000000800000000
>>>>>> rw space: 4089896 [ 32.2% of total] out of 4091904 bytes
>>>>>> [100.0%
>>>>>> used] at 0x0000000800003000
>>>>>> ro space: 7546512 [ 59.4% of total] out of 7548928 bytes
>>>>>> [100.0%
>>>>>> used] at 0x00000008003ea000
>>>>>> md space: 2272 [ 0.0% of total] out of 4096 bytes [
>>>>>> 55.5%
>>>>>> used] at 0x0000000800b1d000
>>>>>> bm space: 184320 [ 1.5% of total] out of 184320 bytes
>>>>>> [100.0%
>>>>>> used] at 0x0000000000000000
>>>>>> ca0 space: 520192 [ 4.1% of total] out of 520192 bytes
>>>>>> [100.0%
>>>>>> used] at 0x00000007bfc00000
>>>>>> oa0 space: 339968 [ 2.7% of total] out of 339968 bytes
>>>>>> [100.0%
>>>>>> used] at 0x00000007bf800000
>>>>>> total : 12689192 [100.0% of total] out of 12701696 bytes [
>>>>>> 99.9% used]
>>>>>>
>>>>>>
>>>>>>
>>>>>>> Developers may not know which logging option
>>>>>>> needs to be specified to enable the output.
>>>>>>>
>>>>>>> One possible solution is to enable -Xlog:cds by default for
>>>>>>> -Xshare:dump, if the output method is converted to use unified
>>>>>>> logging.
>>>>>> I suppose if someone is interested, they can find out the tag
>>>>>> information by reading the documentation? That's the same if you
>>>>>> want to
>>>>>> see the logs for other VM features such as gc or class loading.
>>>>> The above does not seem to be a safe assumption. The less burden that
>>>>> we place on Java developers the better.
>>>>>
>>>>> From a usability point of view, I think the output should be
>>>>> enabled
>>>>> by default.
>>>> The Unified Logging system was added to the VM so that all the JVM
>>>> output used the same mechanism. Having a knowlegable user specify
>>>> -Xlog:cds doesn't seem burdensome.
>>>>
>>> Average Java developers may not have the detailed/ and right knowledge
>>> about the logging system(?).
>>
>> I don't believe that. Logging's been in the system since JDK 9, and
>> it's pretty intuitive.
>>>
>>>> To me, the output has always looked like logging, and not simply
>>>> printing that it succeeded. Also the size percentage output seems
>>>> less
>>>> meaningful now that the archive is compacted before dumping. Most of
>>>> this information is only useful for developers and should be
>>>> -Xlog:cds=info.
>>>>
>>> With Ioi's current change in place, -Xshare:dump now produce no
>>> output. To be able to see any dumping output even for confirmation
>>> purpose, users now need to add -Xlog:cds option explicitly. The
>>> -Xlog:cds gives the original default dumping output and some
>>> additional information. If we can cleanup the -Xlog:cds logging info
>>> by removing the 'Shared file region 4: 0x0002dc18 bytes...' related
>>> output, we can still give user useful and not overwhelming
>>> information, by enabling it by default for -Xshare:dump. It would also
>>> help users to avoid having to type -Xlog:cds when they
>>> experimenting/using with the feature manually. Any particular reason
>>> or concern for not going with that?
>>>
>>> $ bin/java -Xshare:dump
>>>
>>> $ bin/java -Xshare:dump -Xlog:cds
>>> [0.028s][info][cds] narrow_klass_base = 0x0000000800000000,
>>> narrow_klass_shift = 3
>>> [0.028s][info][cds] Allocated temporary class space: 1073741824 bytes
>>> at 0x00000008c0000000
>>> [0.028s][info][cds] Allocated shared space: 3221225472 bytes at
>>> 0x0000000800000000
>>> [0.417s][info][cds] Loading classes to share ...
>>> [1.020s][info][cds] Loading classes to share: done.
>>> [1.020s][info][cds] Shared spaces: preloaded 1187 classes
>>> [1.020s][info][cds] Reading extra data: done.
>>> [1.026s][info][cds] Rewriting and linking classes ...
>>> [1.126s][info][cds] Rewriting and linking classes: done
>>> [2.077s][info][cds] Number of classes 1261
>>> [2.077s][info][cds] instance classes = 1195
>>> [2.077s][info][cds] obj array classes = 58
>>> [2.077s][info][cds] type array classes = 8
>>> [2.077s][info][cds] Updating ConstMethods ...
>>> [2.141s][info][cds] done.
>>> [2.141s][info][cds] Removing unshareable information ...
>>> [2.203s][info][cds] done.
>>> [2.226s][info][cds] Scanning all metaspace objects ...
>>> [2.226s][info][cds] Allocating RW objects ...
>>> [2.552s][info][cds] Allocating RO objects ...
>>> [2.916s][info][cds] Relocating embedded pointers ...
>>> [3.518s][info][cds] Relocating external roots ...
>>> [3.580s][info][cds] Verifying external roots ...
>>> [3.627s][info][cds] Dumping symbol table ...
>>> [3.693s][info][cds] Dumping objects to closed archive heap region ...
>>> [3.775s][info][cds] Dumping objects to open archive heap region ...
>>> [3.863s][info][cds] Relocating
>>> SystemDictionary::_well_known_klasses[] ...
>>> [3.863s][info][cds] Removing java_mirror ...
>>> [3.863s][info][cds] done.
>>> [3.868s][info][cds] Oopmap = 0x0000000800b705c0 ( 16256 bytes) for
>>> heap region 0x00000007ffc00000 ( 520192 bytes)
>>> [3.870s][info][cds] Oopmap = 0x0000000800b74540 ( 10624 bytes) for
>>> heap region 0x00000007ff800000 ( 339968 bytes)
>>> [3.880s][info][cds] Dumping shared data to file:
>>> [3.880s][info][cds]
>>> /usr/local/google/home/jianglizhou/openjdk/jdk/build/linux-x86_64-server-slowdebug/images/jdk/lib/server/classes.jsa
>>>
>>
>> Here.
>>> [3.880s][info][cds] Shared file region 0: 0x000058d8 bytes, addr
>>> 0x0000000800000000 file offset 0x00001000
>>> [3.880s][info][cds] Shared file region 1: 0x00436528 bytes, addr
>>> 0x0000000800006000 file offset 0x00007000
>>> [3.885s][info][cds] Shared file region 2: 0x00739ec0 bytes, addr
>>> 0x000000080043d000 file offset 0x0043e000
>>> [3.895s][info][cds] Shared file region 3: 0x000009a0 bytes, addr
>>> 0x0000000800b77000 file offset 0x00b78000
>>> [3.895s][info][cds] ptrmap = 0x00007fe961b5a230 (187416 bytes)
>>> [3.895s][info][cds] Shared file region 4: 0x0002dc18 bytes, addr
>>> 0x0000000000000000 file offset 0x00b79000
>>> [3.895s][info][cds] Archive heap region 5: 0x00000007ffc00000 -
>>> 0x00000007ffc7f000 = 520192 bytes
>>> [3.895s][info][cds] Shared file region 5: 0x0007f000 bytes, addr
>>> 0x00000007ffc00000 file offset 0x00ba7000
>>> [3.896s][info][cds] Archive heap region 6: 0x0000000000000000 -
>>> 0x0000000000000000 = 0 bytes
>>> [3.896s][info][cds] Shared file region 6: 0x00000000 bytes, addr
>>> 0x0000000000000000 file offset 0x00c26000
>>> [3.896s][info][cds] Archive heap region 7: 0x00000007ff800000 -
>>> 0x00000007ff853000 = 339968 bytes
>>> [3.896s][info][cds] Shared file region 7: 0x00053000 bytes, addr
>>> 0x00000007ff800000 file offset 0x00c26000
>>> [3.896s][info][cds] Archive heap region 8: 0x0000000000000000 -
>>> 0x0000000000000000 = 0 bytes
>>> [3.896s][info][cds] Shared file region 8: 0x00000000 bytes, addr
>>> 0x0000000000000000 file offset 0x00c79000
>>> [3.896s][info][cds] mc space: 22744 [ 0.2% of total] out of
>>> 24576 bytes [ 92.5% used] at 0x0000000800000000
>>> [3.896s][info][cds] rw space: 4416808 [ 33.8% of total] out of
>>> 4419584 bytes [ 99.9% used] at 0x0000000800006000
>>> [3.896s][info][cds] ro space: 7577280 [ 58.0% of total] out of
>>> 7577600 bytes [100.0% used] at 0x000000080043d000
>>> [3.896s][info][cds] md space: 2464 [ 0.0% of total] out of
>>> 4096 bytes [ 60.2% used] at 0x0000000800b77000
>>> [3.896s][info][cds] bm space: 188416 [ 1.4% of total] out of
>>> 188416 bytes [100.0% used] at 0x0000000000000000
>>> [3.896s][info][cds] ca0 space: 520192 [ 4.0% of total] out of
>>> 520192 bytes [100.0% used] at 0x00000007ffc00000
>>> [3.896s][info][cds] oa0 space: 339968 [ 2.6% of total] out of
>>> 339968 bytes [100.0% used] at 0x00000007ff800000
>>> [3.896s][info][cds] total : 13066872 [100.0% of total] out of
>>> 13074432 bytes [ 99.9% used]
>>> [3.896s][info][cds] Detailed metadata info (excluding st regions; rw
>>> stats include md/mc regions):
>>> [3.896s][info][cds] ro_cnt ro_bytes % |
>>> rw_cnt rw_bytes % | all_cnt all_bytes %
>>> [3.896s][info][cds]
>>> --------------------+---------------------------+---------------------------+--------------------------
>>>
>>> [3.896s][info][cds] Class : 0 0 0.0 |
>>> 1261 843432 19.0 | 1261 843432 7.0
>>> [3.896s][info][cds] Symbol : 37883 1491992 19.7 |
>>> 0 0 0.0 | 37883 1491992 12.4
>>> [3.896s][info][cds] TypeArrayU1 : 9274 275872 3.6 |
>>> 1195 244616 5.5 | 10469 520488 4.3
>>> [3.896s][info][cds] TypeArrayU2 : 3093 161104 2.1 |
>>> 0 0 0.0 | 3093 161104 1.3
>>> [3.896s][info][cds] TypeArrayU4 : 1370 87216 1.2 |
>>> 0 0 0.0 | 1370 87216 0.7
>>> [3.896s][info][cds] TypeArrayU8 : 2045 188936 2.5 |
>>> 1195 142840 3.2 | 3240 331776 2.8
>>> [3.896s][info][cds] TypeArrayOther : 0 0 0.0 |
>>> 0 0 0.0 | 0 0 0.0
>>> [3.896s][info][cds] Method : 0 0 0.0 |
>>> 19089 1992200 44.8 | 19089 1992200 16.6
>>> [3.896s][info][cds] ConstMethod : 19089 2956768 39.0 |
>>> 0 0 0.0 | 19089 2956768 24.6
>>> [3.896s][info][cds] MethodData : 0 0 0.0 |
>>> 0 0 0.0 | 0 0 0.0
>>> [3.896s][info][cds] ConstantPool : 1195 1942912 25.6 |
>>> 0 0 0.0 | 1195 1942912 16.2
>>> [3.896s][info][cds] ConstantPoolCache : 0 0 0.0 |
>>> 1195 1193720 26.9 | 1195 1193720 9.9
>>> [3.896s][info][cds] Annotations : 59 1888 0.0 |
>>> 0 0 0.0 | 59 1888 0.0
>>> [3.896s][info][cds] MethodCounters : 0 0 0.0 |
>>> 0 0 0.0 | 0 0 0.0
>>> [3.896s][info][cds] RecordComponent : 0 0 0.0 |
>>> 0 0 0.0 | 0 0 0.0
>>> [3.896s][info][cds] SymbolHashentry : 37883 300216 4.0 |
>>> 0 0 0.0 | 37883 300216 2.5
>>> [3.896s][info][cds] SymbolBucket : 9470 37888 0.5 |
>>> 0 0 0.0 | 9470 37888 0.3
>>> [3.896s][info][cds] StringHashentry : 7227 57320 0.8 |
>>> 0 0 0.0 | 7227 57320 0.5
>>> [3.896s][info][cds] StringBucket : 1806 7232 0.1 |
>>> 0 0 0.0 | 1806 7232 0.1
>>> [3.896s][info][cds] Other : 0 67936 0.9 |
>>> 0 25208 0.6 | 0 93144 0.8
>>> [3.896s][info][cds]
>>> --------------------+---------------------------+---------------------------+--------------------------
>>>
>>> [3.896s][info][cds] Total : 130394 7577280 100.0 |
>>> 23935 4442016 100.0 | 154329 12019296 100.0
>>>
>>
>> Actually, I partially agree with this. I think the table at the end,
>> and maybe even the shared region %ages part could be -Xlog:cds=debug,
>> but all of the output should be under -Xlog:cds={info,debug}.
>>
>> Someone experimenting with CDS should absolutely already know about
>> -Xlog:cds. That's not a stretch. We're trying to get to the jvm not
>> having any tty->print() anymore, and all output is controlled so that
>> users can choose what they see. UL is nice that you have this
>> flexibility to see what you want.
>>
>> So I agree that making the last part of the output -Xlog:cds=debug or
>> even -Xlog:cds+regions=info.
>>
>> thanks,
>> Coleen
>>
>>
>>> Best,
>>> Jiangli
>>>
>>>> Thanks,
>>>> Coleen
>>>>
>>>>> Regards,
>>>>> Jiangli
>>>>>
>>>>>> Thanks
>>>>>> - Ioi
>>>>>>
>>>>>>> Regards,
>>>>>>> Jiangli
>>>>>>>
>>>>>>> On Tue, Dec 17, 2019 at 10:34 PM Ioi Lam <ioi.lam at oracle.com>
>>>>>>> wrote:
>>>>>>>> https://bugs.openjdk.java.net/browse/JDK-8233826
>>>>>>>> http://cr.openjdk.java.net/~iklam/jdk15/8233826-cds-change-tty-to-ul.v01/
>>>>>>>>
>>>>>>>>
>>>>>>>> During CDS dumping, a few messages are printed out unconditionally
>>>>>>>> using tty->print_cr(). This patch changes the message to use
>>>>>>>> log_info(cds) instead.
>>>>>>>>
>>>>>>>> Some test cases were expecting the messages in stdout. I modified
>>>>>>>> these tests to explicitly pass -Xlog:cds.
>>>>>>>>
>>>>>>>> Thanks
>>>>>>>> - Ioi
>>>>>>>>
>>
>
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