Dear Serguei,
Here is my reply for your question about non-numeric value for
“parallel” (somehow the thread of replay became out of order, not sure why).
> >> What is going to happen if the resulting 'parallel' substring above
>is not a number?
> The error handling logic locates at
>http://cr.openjdk.java.net/~lzang/jmap-8214535/8215624/webrev_11/src/hotspot/share/services/attachListener.cpp.frames.html,
> (line 276-284)
> Generally, the result is error message will be print if “parallel” is
>illegal. An example output would be:
> ############################
> $ time jmap -histo:parallel=c 26233
> Exception in thread "main"
> com.sun.tools.attach.AttachOperationFailedException: Invalid parallel thread
> number: [c]
> at
>jdk.attach/sun.tools.attach.VirtualMachineImpl.execute(VirtualMachineImpl.java:227)
> at
>jdk.attach/sun.tools.attach.HotSpotVirtualMachine.executeCommand(HotSpotVirtualMachine.java:309)
> at
>jdk.jcmd/sun.tools.jmap.JMap.executeCommandForPid(JMap.java:133)
> at
>jdk.jcmd/sun.tools.jmap.JMap.histo(JMap.java:206)
> at
>jdk.jcmd/sun.tools.jmap.JMap.main(JMap.java:112)
>
> ############################
>
> Hi Serguei, Paul and Stefan.
> Moreover, I will made a new changeset with following changes:
> * Print error message + usage when parameter check fail in Jmap.java
> *Retrive the histo logic that if “all” and “live” are set at same time,
> use “live”, rather than print error message. (not sure which one is better :P)
My last point is to retrive the behavior for compatibility. And do you think
make a separate enhancement about spec is reasonable ?
Thanks!
BRs,
Lin
From: "serguei.spit...@oracle.com" <serguei.spit...@oracle.com>
Date: Tuesday, August 11, 2020 at 5:11 AM
To: "linzang(臧琳)" <linz...@tencent.com>, "Hohensee, Paul"
<hohen...@amazon.com>, Stefan Karlsson <stefan.karls...@oracle.com>, David
Holmes <david.hol...@oracle.com>, serviceability-dev
<serviceability-dev@openjdk.java.net>, "hotspot-gc-...@openjdk.java.net"
<hotspot-gc-...@openjdk.java.net>
Subject: Re: RFR(L): 8215624: add parallel heap inspection support for jmap
histo(G1)(Internet mail)
Hi Lin,
On 8/7/20 03:41, linzang(臧琳) wrote:
Dear Serguei,
Thanks a lot for your review!
>> The spec says nothing if the new option 'parallel' is mandatory or optional.
>> Also, (it was before your fix) the spec does not say if the options 'live'
>> and 'all' are mutually exclusive.
For “parallel”, the spec adds “parallel=0” is the default behavior.
So my assumption is if parallel is not used, it will be 0. Do you think it is
ok ? is it necessary to obviously add comments like “if no parallel is set, use
the default value 0”?
It'd be nice to make it clear.
But the CSR will need to be updated.
In fact, I did not want you to go through this cycle again.
But maybe it is worth to improve the specs in this regard.
May be Paul has some alternative suggestions.
For “live” and “all”, before the changeset , I see the logic from the
code is that both of them can be set at the same time, and the “live” will take
effect. IMHO this may be a little confused. So I made the change, not sure
whether I should keep the same behavior as before in this change?
This is better to clearly specify what is allowed and what is the behavior.
And I like your idea of printing more error msg if something wrong
with the options setting, but I checked that before the change, if there is not
a match option, it only print usage. and not only jmap -histo but also jmap
-dump has this issue, do you agree if I fix both in the changeset?
Yes, it'd be nice to make it clear in both specs.
>> What is going to happen if null is passed in place of
parallel here? :
The default value 0 will be used if no “parallel” option is set.
Okay, thanks.
>> Should the lines 193-195 be moved after the
line 202?
I don’t think so, the logic is a little different. At line 193, the
case is “parallel=<blank>”. If move them to line 203, it mean “parallel” is
not optional.
Okay, I see what you mean.
The problem is that the help/spec says nothing about the flag 'parallel' as
being optional.
I also asked this question:
Q: What is going to happen if the resulting 'parallel' sub-string above is
not a number?
Thanks,
Serguei
Thanks!
BRs,
Lin
From: mailto:serguei.spit...@oracle.com mailto:serguei.spit...@oracle.com
Date: Friday, August 7, 2020 at 3:28 PM
To: "linzang(臧琳)" mailto:linz...@tencent.com, "Hohensee, Paul"
mailto:hohen...@amazon.com, Stefan Karlsson mailto:stefan.karls...@oracle.com,
David Holmes mailto:david.hol...@oracle.com, serviceability-dev
mailto:serviceability-dev@openjdk.java.net,
mailto:hotspot-gc-...@openjdk.java.net mailto:hotspot-gc-...@openjdk.java.net
Subject: Re: RFR(L): 8215624: add parallel heap inspection support for jmap
histo(G1)(Internet mail)
Hi Lin,
Not sure, I fully understand the spec update and the options processing in the
file:
http://cr.openjdk.java.net/~lzang/jmap-8214535/8215624/webrev_11/src/jdk.jcmd/share/classes/sun/tools/jmap/JMap.java.frames.html
The spec says nothing if the new option 'parallel' is mandatory or optional.
Also, (it was before your fix) the spec does not say if the options 'live' and
'all' are mutually exclusive.
The JMap.java implementation just print usage in two cases:
191 } else if (subopt.startsWith("parallel=")) {
192 parallel = subopt.substring("parallel=".length());
193 if (parallel == null) {
194 usage(1);
195 }
...
200 if (set_live && set_all) {
201 usage(1);
202 }
It is not that helpful as the usage does not explain anything about these
corner cases.
Also, it allows to pass no parallel option.
What is going to happen if null is passed in place of parallel here? :
206 executeCommandForPid(pid, "inspectheap", liveopt, filename,
parallel);
Should the lines 193-195 be moved after the line 202?
Thanks,
Serguei
On 8/5/20 18:59, linzang(臧琳) wrote:
Thanks Paul!
And I have verified this change could build success in windows.
BRs,
Lin
On 2020/8/6, 4:17 AM, "Hohensee, Paul" mailto:hohen...@amazon.com wrote:
Two tiny nits that don't need a new webrev:
In heapInspection.cpp, you don't need to cast missed_count to uintx in the
call to log_info().
In heapInspection.hpp, you can delete two of the three blank lines before
#endif // SHARE_MEMORY_HEAPINSPECTION_HPP
Thanks,
Paul
On 8/5/20, 6:46 AM, "linzang(臧琳)" mailto:linz...@tencent.com wrote:
Hi Paul, Stefan and Serguei,
Here I uploaded a new changeset, would you like to help review
again?
Webrev:
http://cr.openjdk.java.net/~lzang/jmap-8214535/8215624/webrev_11/
Delta (based on webrev10):
http://cr.openjdk.java.net/~lzang/jmap-8214535/8215624/webrev_11_delta/
P.S. I am in process of building it on windows environment for a
double check. May update result later. Thanks!
BRs,
Lin
