RFR(S) 8233826 Change CDS dumping tty->print_cr() to unified logging
Jiangli Zhou
jianglizhou at google.com
Thu Dec 19 00:34:03 UTC 2019
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(?).
> 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
[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
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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