Dear Lin,
I looked at your CSR and have comments/questions below.
> Add the options "chunkcount=" and "maxfilesize=" to JMap -histo to
improve JMap's ability
Ability to what? The statement above is no complete, it even does not
have a dot.
Most likely it should have something like:
... to improve JMap with the ability to dump heap histogram
incrementally.
> Currently the "JMap -histo" tool doesn't support to dump intermediate
result,
> which is useful when heap is large and dump whole heap with "jmap
-histo" cause stuck.
A suggestion is to rephrase it to something like:
Now, the "jmap -histo" command can not dump intermediate result,
which is useful if the heap is large and dumping the whole heap
can be stuck.
> Add "chunkcount=" and "maxfilesize=" option that let JMap -histo to
dump intermediate result incrementally.
A suggestion is to rephrase to something like:
Add two new command options to control incremental dumping of
intermediary data:
chunkcount=<N>, <provide explanation which is more complete than
in the help below>
maxfilesize=<N>, <provide explanation which is more complete than
in the help below>
You need to explain now this parameters are going to be used and their
semantics.
Q1: Then what is the expected behavior of this incremental dump?
Q2: What happens if just one of options is used?
Q3: What are default values?
Q4: Does enabling incremental dump disable full dump?
This is still good to have as additional explanation for new options:
*
If new options "chunkcount=" and "maxfilesize=" options are not set
then the jmap -histo behaves as before
*
Negative values or values larger than the max of uintx for
"chunkcount" and "maxfilesize" are not allowed
Please, be consistent with having or missing dots at the end of statements.
|System.err.println(" incremental dump support:"); + System.err.println("
chunkcount=<N> object number counted (in Kilo) to trigger incremental
dump"); + System.err.println(" maxfilesize=<N> size limit of incremental
dump file (in KB)"); |
From this description is not clear at all what does the chunkcount mean.
Is it to define how many heap objects are dumped in one chunk?
If so, would it better to name it chunksize instead where chunksize is
measured in heap objects?
Then would it better to use the same units to define the maxfilesize as
well?
(I'm not insisting on this, just asking.)
|+ System.err.println(" Specify chunkcont to non-zero will enable
incremental dump."); Does it make sense to consider some reasonable
default values for |||chunkcont| and |||maxfilesize|? Then they could be used with no value: "chunkcount" or
"chunkcount=". + System.err.println(" The incremental data file is named
\"Histo_Dump_Temp.dump\" under the same path specified by \"file=\"
option.");|
I don't like that "Dump/dump" suffix is used twice.
At least, this is worth to consider something like this:
|\"IncrementalHisto.dump\".
|Also, I'd suggest to re-design all this a little bit.
What about adding new option to force incremental dump:
incremental{=<file_name>} with the default file name
|\"IncrementalHisto.dump\".|
With this option, the options chunkcount and maxfilesize can be omitted
implying default values.
But we need to look at the overall jmap design to make sure this
suggestion is aligned with other options.||
Thanks,
Serguei
On 4/14/19 7:54 PM, 臧琳 wrote:
Dear Jc,
Thanks a lot for your suggestions, I have updated the CSR.
Hi All,
May I get more review about the webrev and CSR,
Webrev:
http://cr.openjdk.java.net/~lzang/jmap-8214535/8215623/webrev.06/
<http://cr.openjdk.java.net/%7Elzang/jmap-8214535/8215623/webrev.06/>
CSR: https://bugs.openjdk.java.net/browse/JDK-8222319.
BRs,
Lin
在 2019年4月13日，上午2:15，Jean Christophe Beyler <jcbey...@google.com
<mailto:jcbey...@google.com>> 写道：
Hi Lin,
You could state in the CSR:
- That not using the new flags makes the system behave as before;
so it is a nop if you don't use the new flags
- What happens if the flags are passed negative values?
- What happens if the flags are passed crazy big numbers?
Finally, I'd put a link to the current webrev if someone wanted more
information.
Apart from that, it looks good to me (I might skip the diff as you
put the output below) the text could just say: here is the new usage
text (maxchunk and maxfilesize are new)
Thanks,
Jc
On Wed, Apr 10, 2019 at 11:56 PM 臧琳 <zangl...@jd.com
<mailto:zangl...@jd.com>> wrote:
Dear All,
I have created a CSR at
https://bugs.openjdk.java.net/browse/JDK-8222319.
May I ask your help to review it? Thanks!
BRs,
Lin
在 2019年4月11日，上午11:22，臧琳 <zangl...@jd.com
<mailto:zangl...@jd.com>> 写道：
Sorry, it should be CSR ticket
Thanks，
Lin
在 2019年4月11日，上午11:16，臧琳 <zangl...@jd.com
<mailto:zangl...@jd.com>> 写道：
Also realized it requires a JCP ticket, I will create it.
Cheers,
Lin
在 2019年4月11日，上午10:26，臧琳 <zangl...@jd.com
<mailto:zangl...@jd.com>> 写道：
Dear JC,
Thanks so much, I suddenly realized your way is exactly
what I want.
And here is new wehbrev.
http://cr.openjdk.java.net/~lzang/jmap-8214535/8215623/webrev.06/
<http://cr.openjdk.java.net/%7Elzang/jmap-8214535/8215623/webrev.06/>
BRs,
Lin
在 2019年4月11日，上午4:40，Jean Christophe Beyler
<jcbey...@google.com <mailto:jcbey...@google.com>> 写道：
Hi Lin,
What I meant about the helper method was to not do this:
+ private static String add_option(String cmd, String opt) {
+ if (opt.equals("")) {
+ return cmd;
+ }
+ return cmd + opt + ",";
+ }
+
but to do this:
+ private static String add_option(String cmd, String opt) {
+ if (cmd.isEmpty()) {
+ return opt;
+ }
+ return cmd + "," + opt;
+ }
+
That way you only put the ',' when needed,
Jc
On Wed, Apr 10, 2019 at 5:33 AM 臧琳 <zangl...@jd.com
<mailto:zangl...@jd.com>> wrote:
Dear Jc,
Thanks a lot for your comments, here is the refined
webrev. May I ask your help to review again?
http://cr.openjdk.java.net/~lzang/jmap-8214535/8215623/webrev.05/
<http://cr.openjdk.java.net/%7Elzang/jmap-8214535/8215623/webrev.05/>
BRs,
Lin
在 2019年4月4日，上午4:57，Jean Christophe Beyler
<jcbey...@google.com <mailto:jcbey...@google.com>> 写道：
Hi Lin,
Just a few nits to be honest:
-
http://cr.openjdk.java.net/~lzang/jmap-8214535/8215623/webrev.04/src/hotspot/share/utilities/ostream.cpp.udiff.html
<http://cr.openjdk.java.net/%7Elzang/jmap-8214535/8215623/webrev.04/src/hotspot/share/utilities/ostream.cpp.udiff.html>
-> I don't think it's a good idea to just pass a char*
and implicitly imagine it is 256 in length
-> Should we not add that length as a parameter? btw,
the test you have len > 255 is a bit too restrictive no?
Technically you should wait until you find the last '/'
and then test there no?
(technically we could use strrchr, no?)
http://cr.openjdk.java.net/~lzang/jmap-8214535/8215623/webrev.04/src/jdk.jcmd/share/classes/sun/tools/jmap/JMap.java.udiff.html
<http://cr.openjdk.java.net/%7Elzang/jmap-8214535/8215623/webrev.04/src/jdk.jcmd/share/classes/sun/tools/jmap/JMap.java.udiff.html>
-> the adding of the "," seems a bit off; I think it
would be smarter to just have a helper add_option to
cmdline that checks if it is not empty, then add "," and
the new option
-> otherwise you always end the "," if there are more
options even if you are ignoring them, no?
Finally:
} else if (subopt.equals("live")) {
- liveopt = "-live";
+ // Add '-' for compatibility.
+ cmdline += "-" + subopt;
for consistency with how you do it for "all", should
this not be:
} else if (subopt.equals("live")) {
- liveopt = "-live";
+ // Add '-' for compatibility.
+ cmdline += "-live";
Thanks,
Jc
On Mon, Apr 1, 2019 at 5:18 AM 臧琳 <zangl...@jd.com
<mailto:zangl...@jd.com>> wrote:
Dear All，
Here I updated the latest changeset which did
the following refine:
* fixed the compatibility issues so that old
version of jmap can work normally with latest changeset.
* revised the code for parsing the jmap histo
arguments.
* revised the logic for incremental dumping of
jmap histo.
The main change of this webrev is making all
arguments passed to virtual machine as one line. So
there is no need to care about the max argument
count limitation. And hence resolved the
compatibility issues as discussed in
http://mail.openjdk.java.net/pipermail/serviceability-dev/2019-March/027338.html
May I ask your help to review?
http://cr.openjdk.java.net/~lzang/jmap-8214535/8215623/webrev.04/
<http://cr.openjdk.java.net/%7Elzang/jmap-8214535/8215623/webrev.04/>
BRs,
Lin
在 2019年2月26日，上午10:50，臧琳 <zangl...@jd.com
<mailto:zangl...@jd.com>> 写道：
Dear All,
I have revised the webrev at
http://cr.openjdk.java.net/~xiaofeya/8215623/webrev.02/
<http://cr.openjdk.java.net/%7Exiaofeya/8215623/webrev.02/>.
May I ask your help for reviewing? Thanks
BRs,
Lin
-----Original Message-----
From: 臧琳
Sent: Friday, January 25, 2019 9:01 AM
To: Hohensee, Paul <hohen...@amazon.com
<mailto:hohen...@amazon.com>>; serviceability-
d...@openjdk.java.net <mailto:d...@openjdk.java.net>
Subject: Re: [RFR]8215623: Add incremental dump
for jmap histo
Dear All,
May I get more review about this webrev?
Webrev:
http://cr.openjdk.java.net/~xiaofeya/8215623/webrev.01/
<http://cr.openjdk.java.net/%7Exiaofeya/8215623/webrev.01/>
Bug:
https://bugs.openjdk.java.net/browse/JDK-8215623
Thanks!
Lin
________________________________________
From: 臧琳
Sent: Wednesday, January 9, 2019 9:46:55 AM
To: Hohensee, Paul;
serviceability-dev@openjdk.java.net
<mailto:serviceability-dev@openjdk.java.net>
Subject: RE: [RFR]8215623: Add incremental dump
for jmap histo
Hi Paul and All,
Thanks a lot for your review and comments, I
have updated the webrev to
Webrev:
http://cr.openjdk.java.net/~xiaofeya/8215623/webrev.01/
<http://cr.openjdk.java.net/%7Exiaofeya/8215623/webrev.01/>
Bug: https://bugs.openjdk.java.net/browse/JDK-8215623
Would you like to help review it. Thanks.
BRs
Lin
From: 臧琳
Sent: Monday, January 7, 2019 7:14 PM
To: Hohensee, Paul <hohen...@amazon.com
<mailto:hohen...@amazon.com>>; serviceability-
d...@openjdk.java.net
<mailto:d...@openjdk.java.net>; 臧琳 <zangl...@jd.com
<mailto:zangl...@jd.com>>
Subject: RE: [RFR]8215623: Add incremental dump
for jmap histo
And another way is to add a argument
“IncrementalFile=<path>”,which
specifies the location for saving the intermediate
data file. And if it is not
specified, incremental data will dump to “out”.
What do you think?
Thanks,
Lin
From: 臧琳
Sent: Monday, January 7, 2019 7:02 PM
To: Hohensee, Paul
<hohen...@amazon.com
<mailto:hohen...@amazon.com><mailto:hohen...@amazon.com
<mailto:hohen...@amazon.com>>>; serviceability-
d...@openjdk.java.net
<mailto:d...@openjdk.java.net><mailto:serviceability-dev@openjdk.java.net
<mailto:serviceability-dev@openjdk.java.net>>
Subject: 答复: [RFR]8215623: Add incremental dump
for jmap histo
Dear Paul,
Thanks for your review, I agree your
suggestion to make incremental
general. and
I think the incremental file is better to
be different with the file or the
"out", because
in future the parallel histo will have each thread
individually dump their data,
and I want
it to be lock-free, so each thread need to dump to
their own file. The final
data
will be sum up and dump to the file that
"filename=<file>" specified.
Moreover, the incremental
file contains intermediate data, if it is dumped
to "<file>", it more or less
"pollute" the final file (final file that contains
lots intermediate data).
so the logic is that incremental data will
be dumped to a file named
"Histo_Dump_Temp.dump",
if the "filename" is assigned, the
"Histo_Dump_Temp.dump" will be
generated under the same folder,
if "filename" not specified, it will dump to
current dir. And if "chunkcount" is 0
or max_int, or "maxfilesize" is 0, the incremental
dump will be disabled.
________________________________
发件人: Hohensee, Paul
<hohen...@amazon.com
<mailto:hohen...@amazon.com><mailto:hohen...@amazon.com
<mailto:hohen...@amazon.com>>>
发送时间: 2019年1月1日 4:56
收件人: 臧琳; serviceability-dev@openjdk.java.net
<mailto:serviceability-dev@openjdk.java.net><mailto:serviceability-
<mailto:serviceability->
d...@openjdk.java.net <mailto:d...@openjdk.java.net>>
主题: Re: [RFR]8215623: Add incremental dump for
jmap histo
As for 8215622, update the copyright dates to 2019
please, since this won’t
get pushed until then.
You might generalize the implementation so that
all inspections are done
incrementally, and parameterize
RecordInstanceClosure with the incremental
threshold. “incremental” could become
“chunkcount=<n>”, where <n>
defaults to infinity (max value of size_t).
I’d not use a default file name when “chunkcount”
is specified, I’d just write to
whatever the output stream is. “chunkcount” is
then independent of “file”.
I’d add another histo argument for the maximum
file size, call it “maxfilesize”,
and parameterize RecordInstanceClosure with it.
Default would be infinity
(max value of size_t).
If you want to make it easy to use your 8k and 5mb
chunkcount and
maxfilesize combination, you could redefine your
original “incremental”
argument as syntactic sugar for
“chunkcount=8k,maxfilesize=5m”.
INCREMENTAL_THRESHOLD and MAX_INCREMENTAL_FILESIZE
become
DEFAULT_CHUNKSIZE and MAX_FILE_SIZE, are both set
to max size_t, and
should be defined as “const int” within
RecordInstanceClosure.
Thanks,
Paul
From: serviceability-dev <serviceability-dev-
boun...@openjdk.java.net
<mailto:boun...@openjdk.java.net><mailto:serviceability-dev-
<mailto:serviceability-dev->
boun...@openjdk.java.net
<mailto:boun...@openjdk.java.net>>> on behalf of 臧琳
<zangl...@jd.com
<mailto:zangl...@jd.com><mailto:zangl...@jd.com
<mailto:zangl...@jd.com>>>
Date: Thursday, December 20, 2018 at 11:13 PM
To: "serviceability-dev@openjdk.java.net
<mailto:serviceability-dev@openjdk.java.net><mailto:serviceability-
<mailto:serviceability->
d...@openjdk.java.net
<mailto:d...@openjdk.java.net>>" <serviceability-
d...@openjdk.java.net
<mailto:d...@openjdk.java.net><mailto:serviceability-dev@openjdk.java.net
<mailto:serviceability-dev@openjdk.java.net>>>
Subject: [RFR]8215623: Add incremental dump for
jmap histo
Hi All,
May I ask your help to review this patch for
enhance jmap –histo.
It adds the “incremental” arguments that allow
jmap –histo to incrementally
save the intermediate data into a temp file.
The intermediate data is dumped incrementally and
write to a rolling file,
which limit the size of the temp file to be small.
This is useful for user to get intermediate
results when jmap/jvm process is
killed accidentally. Especially when the heap is
large.
This patch is also part of the enhancement
described in
https://bugs.openjdk.java.net/browse/JDK-8214535.
Webrev:
http://cr.openjdk.java.net/~xiaofeya/8215623/webrev.00/
<http://cr.openjdk.java.net/%7Exiaofeya/8215623/webrev.00/>
Bug: https://bugs.openjdk.java.net/browse/JDK-8215623
Thanks.
BRs,
Lin
--
Thanks,
Jc
--
Thanks,
Jc
--
Thanks,
Jc
