Hi Gary and Chris,
Below is the table that shows what jdb output is printed when a breakpoint is
hit depending on what suspended policy is used:
SUSPEND POLICY | PROMPT PRINTED | LOCATION PRINTED
---------------------------------------
|---------------------------|--------------------------
SUSPEND_ALL. | yes, e.g. "main[1]" | yes
--------------------------------------- |--------------------------
|--------------------------
SUSPEND_EVENT_THREAD | no | no
----------------------------------------|------------------------
--|--------------------------
SUSPEND_ALL. | no |
no
The fix changes this behavior as the following:
SUSPEND POLICY | PROMPT PRINTED. | LOCATION PRINTED
---------------------------------------
|----------------------------|--------------------------
SUSPEND_ALL. | yes , e.g. "main[1]" | yes
---------------------------------------
|----------------------------|--------------------------
SUSPEND_EVENT_THREAD | yes , ">" | yes
----------------------------------------|---------------------------
|--------------------------
SUSPEND_ALL. | yes, ">". |
yes
Could you please say is it OK for you or you want that the location was printed
only for SUSPEND_ALL case? Or probably just leave all behavior unchanged and
close the bug as "not an issue"?
Regarding settable prompt... As I understand Gary's original concern was that
waiting in tests for a simple prompt " > " (> ) could be unreliable if
this substring somehow appears in the output of the test program and the
suggestion was to use more specific patterns for the cases when the full prompt
(thread_name[frame_index]) is not printed ( e.g. when the current thread is
not set). However, we need somehow pass this pattern to Jdb.command(JdbCommand)
method otherwise it would keep waiting for the full prompt and fail with the
timeout. Probably I am missing something here...
Thanks!
Best regards,
Daniil
On 10/19/18, 12:54 AM, "[email protected]" <[email protected]> wrote:
It's not clear to me if the omitted location information for the non
stopping
cases was intentional or not. It may be sufficient to know that the
event fired
without the extra information.
I don't think a settable prompt is required either. There are plenty of
jdb commands that
could be used with the wait for message in tests that need to
synchronize at a specific
point in the test sequence.
I don't think we see wait for simple prompt in any of the tests, because it
is not reliable enough.
On 10/18/18 11:53 AM, Daniil Titov wrote:
> Hi Gary,
>
> Currently when a breakpoint is hit the message "Breakpoint hit:" is
printed in the debugger output. What we do in this fix we just add more
information about what exact breakpoint is hit. Do you suggest we should not
print this line at all if suspend policy is SUSPEND_NONE? If so then it is not
clear what is the use of the command "stop go ..." would be. Regarding waiting
for the simple prompt, we could change JDbCommand to have a field to store a
prompt pattern and use this pattern (if it was set) when waiting for command to
complete. In tests when required we would set the pattern in JdbCommand to more
complicated one matching a specific output we are expecting at this particular
step. Do you think it would be a better approach?
>
> Thanks!
>
> Best regards,
> Daniil
>
>
>
> On 10/18/18, 4:09 AM, "Gary Adams" <[email protected]> wrote:
>
> I'm not certain that we should be printing locations or prompts for
> events when the vm has not been suspended. This looks OK for the
> simple test case we are working on here, but in real life there may
> be a lot more output produced.
>
> The user has to select a specific thread before additional commands
> can be performed in the correct context. e.g. threads, thread n,
where, ...
> So the information is available to the user. It doesn't have to be
> produced at the time the event is processed.
>
> I'm uncomfortable putting too much trust in waiting for the simple
prompt,
> because there is too great a chance of false positives on such a
small
> marker.
>
>
> On 10/17/18, 8:50 PM, Daniil Titov wrote:
> > Hi Chris, Alex and JC,
> >
> > I created a separate issue to deal with "non-atomic" jdb output at
https://bugs.openjdk.java.net/browse/JDK-8212626 .
> >
> > Please review an updated fix that includes the changes Alex
suggested.
> >
> > Webrev: http://cr.openjdk.java.net/~dtitov/8211736/webrev.04
> > Issue: https://bugs.openjdk.java.net/browse/JDK-8211736
> >
> > Thanks!
> > --Daniil
> >
> >
> > On 10/17/18, 5:06 PM, "Daniil Titov"<[email protected]>
wrote:
> >
> > Hi Chris,
> >
> > The previous email was accidentally fired before I managed to
type anything in. Sorry for confusion.
> >
> > Jdb constantly reads new commands from System.in despite
whether the breakpoint is hit and/or the prompt is printed.
> >
> > cat -n
src/jdk.jdi/share/classes/com/sun/tools/example/debug/tty/TTY.java
> >
> > 786 // Process interactive commands.
> > 787 MessageOutput.printPrompt();
> > 788 while (true) {
> > 789 String ln = in.readLine();
> > 790 if (ln == null) {
> > 791 /*
> > 792 * Jdb is being shutdown
because debuggee exited, ignore any 'null'
> > 793 * returned by readLine()
during shutdown. JDK-8154144.
> > 794 */
> > 795 if (!isShuttingDown()) {
> > 796
MessageOutput.println("Input stream closed.");
> > 797 }
> > 798 ln = "quit";
> > 799 }
> > 800
> > 801 if (ln.startsWith("!!")&&
lastLine != null) {
> > 802 ln = lastLine +
ln.substring(2);
> > 803
MessageOutput.printDirectln(ln);// Special case: use printDirectln()
> > 804 }
> > 805
> > 806 StringTokenizer t = new
StringTokenizer(ln);
> > 807 if (t.hasMoreTokens()) {
> > 808 lastLine = ln;
> > 809 executeCommand(t);
> > 810 } else {
> > 811 MessageOutput.printPrompt();
> > 812 }
> > 813 }
> > 814 } catch (VMDisconnectedException e) {
> > 815
handler.handleDisconnectedException();
> > 816 }
> >
> > Below is a sample debug session for the following test class
that sends commands "threads" and "quit"
> > 1 public class LoopTest {
> > 2 public static void main(String[] args)
throws Exception {
> > 3 Thread thread = Thread.currentThread();
> > 4 while(true) {
> > 5 print(thread);
> > 6 Thread.sleep(5000);
> > 7 }
> > 8 }
> > 9
> > 10 public static void print(Object obj) {
> > 11 //System.out.println(obj);
> > 12 }
> > 13 }
> >
> > datitov-mac:work datitov$
~/src/jdk-hs/build/macosx-x64-debug/images/jdk/bin/jdb LoopTest
> > Initializing jdb ...
> > > stop go at LoopTest:6
> > Deferring breakpoint LoopTest:6.
> > It will be set after the class is loaded.
> > > run
> > run LoopTest
> > Set uncaught java.lang.Throwable
> > Set deferred uncaught java.lang.Throwable
> > >
> > VM Started: Set deferred breakpoint LoopTest:6
> >
> > Breakpoint hit: "thread=main", LoopTest.main(), line=6 bci=8
> > 6 Thread.sleep(5000);
> >
> > Breakpoint hit: "thread=main", LoopTest.main(), line=6 bci=8
> > 6 Thread.sleep(5000);
> > threads
> > Group system:
> > (java.lang.ref.Reference$ReferenceHandler)0x172 Reference
Handler running
> > (java.lang.ref.Finalizer$FinalizerThread)0x173 Finalizer
cond. waiting
> > (java.lang.Thread)0x174 Signal
Dispatcher running
> > Group main:
> > (java.lang.Thread)0x1 main
sleeping
> > Group InnocuousThreadGroup:
> > (jdk.internal.misc.InnocuousThread)0x197
Common-Cleaner cond. waiting
> > >
> > Breakpoint hit: "thread=main", LoopTest.main(), line=6 bci=8
> > 6 Thread.sleep(5000);
> >
> > Breakpoint hit: "thread=main", LoopTest.main(), line=6 bci=8
> > 6 Thread.sleep(5000);
> > quit
> > Breakpoint hit: "thread=main", LoopTest.main(), line=6 bci=8
> > 6 Thread.sleep(5000);
> >
> > datitov-mac:work datitov$
> >
> > I think we could print a simple prompt in this case as Alex
suggested.
> >
> > Best regards,
> > Daniil
> >
> > On 10/17/18, 3:52 PM, "Chris
Plummer"<[email protected]> wrote:
> >
> > What is the jdb state for a breakpoint with SUSPEND_NONE?
Can you
> > actually type in commands even though no threads are
suspended?
> >
> > Chris
> >
> > On 10/17/18 3:31 PM, Alex Menkov wrote:
> > > Hi Daniil, Chris,
> > >
> > > As far as I understand, the fix does not completely
fixes all
> > > "non-atomic" output issues (at least
TTY.executeCommand still prints
> > > prompt separately), so I agree that handle it as
separate issue would
> > > be better.
> > > Unfortunately I don't know Gary's ideas for the issue.
> > >
> > > About the fix for print prompt:
> > > 1) TTY.java:
> > > + // Print current location if suspend
policy is SUSPEND_NONE
> > > I suppose you mean "Print breakpoint location"
> > >
> > > 2) Does it make sense to use printCurrentLocation for
> > > SUSPEND_EVENT_THREAD?
> > > Is it expected to print something different from
printBreakpointLocation?
> > >
> > > 3) I don't quite understand why we don't print simple
prompt for
> > > SUSPEND_NONE. IIUC jdb can accept new command in both
> > > SUSPEND_EVENT_THREAD and SUSPEND_NONE cases (prompt
shows that jdb
> > > waits for next command, right?)
> > >
> > > 4) JdbStopThreadTest.java
> > > New line line in Java regexp is "\\R"
> > >
> > > --alex
> > >
> > > On 10/17/2018 10:47, Chris Plummer wrote:
> > >> Hi Alex,
> > >>
> > >> I think the tty buffering should be a separate bug
fix, and I'd also
> > >> like input from Gary on it since he had tried
something similar at
> > >> one point. It should probably also include a
multithread test to
> > >> prove the fix is working (after first getting the
test to fail
> > >> without the changes).
> > >>
> > >> thanks,
> > >>
> > >> Chris
> > >>
> > >> On 10/16/18 8:59 PM, Daniil Titov wrote:
> > >>> Hi Alex, Chris and JC,
> > >>>
> > >>> Please review an updated version of the patch that
addresses these
> > >>> issues.
> > >>>
> > >>> Webrev:
http://cr.openjdk.java.net/~dtitov/8211736/webrev.03/
> > >>> Issue:
https://bugs.openjdk.java.net/browse/JDK-8211736
> > >>>
> > >>> Thanks!
> > >>> --Daniil
> > >>>
> > >>>
> > >>> On 10/12/18, 9:52 AM, "Alex
Menkov"<[email protected]> wrote:
> > >>>
> > >>> Hi Daniil,
> > >>> 1) +1 for printCurrentLocation when
suspendPolicy != SUSPEND_ALL
> > >>> 2) wrong indent in JdbStopThreadTest.java:
> > >>> 36 import lib.jdb.JdbCommand;
> > >>> 37 import lib.jdb.JdbTest;
> > >>> 3) I think it would be better to make
waitForSimplePrompt
> > >>> property of
> > >>> JdbCommand (like JdbCommand.allowExit)
> > >>>
jdb.command(JdbCommand.run().replyIsSimplePrompt());
> > >>> looks much clearer than
> > >>> jdb.command(JdbCommand.run(), true);
> > >>> 4) (TTY.java)
> > >>> MessageOutput.lnprint("Breakpoint hit:");
> > >>> + // Print current location and prompt if
suspend policy is
> > >>> SUSPEND_EVENT_THREAD.
> > >>> + // In case of SUSPEND_ALL policy this is
handled by
> > >>> vmInterrupted()
> > >>> method.
> > >>> + if (be.request().suspendPolicy() ==
> > >>> EventRequest.SUSPEND_EVENT_THREAD) {
> > >>> +
printCurrentLocation(ThreadInfo.getThreadInfo(be.thread()));
> > >>> + MessageOutput.printPrompt();
> > >>> + }
> > >>> We have 3 separate outputs.
> > >>> If we have several concurrent threads, we can
easy get mess of
> > >>> outputs
> > >>> from different threads.
> > >>> I think it would be better to print everything
in a single chunk.
> > >>> I suppose TTY has other places with similar
"non-atomic"
> > >>> output, so
> > >>> maybe revising TTY output should be handled by
separate issue.
> > >>> --alex
> > >>> On 10/11/2018 22:00, Chris Plummer wrote:
> > >>> > Hi Daniil,
> > >>> >
> > >>> > Can you send output from an example jdb
session?
> > >>> >
> > >>> > Do you think maybe we should also call
printCurrentLocation()
> > >>> when the
> > >>> > suspend policy is NONE?
> > >>> >
> > >>> > There's a typo in the following line. The
space is on the
> > >>> wrong side of
> > >>> > the comma.
> > >>> >
> > >>> > 72
jdb.command(JdbCommand.stopThreadAt(DEBUGGEE_CLASS
> > >>> ,bpLine));
> > >>> >
> > >>> > thanks,
> > >>> >
> > >>> > Chris
> > >>> >
> > >>> > On 10/11/18 8:02 PM, Daniil Titov wrote:
> > >>> >>
> > >>> >> Thank you, JC!
> > >>> >>
> > >>> >> Please review an updated version of the
patch that fixes
> > >>> newly added
> > >>> >> test for Windows platform (now it uses
system dependent line
> > >>> >> separator string).
> > >>> >>
> > >>> >>
Webrev:http://cr.openjdk.java.net/~dtitov/8211736/webrev.02/
> > >>> >>
<http://cr.openjdk.java.net/%7Edtitov/8211736/webrev.02/>
> > >>> >>
> > >>> >> Issue:
https://bugs.openjdk.java.net/browse/JDK-8211736
> > >>> >>
> > >>> >> Best regards,
> > >>> >>
> > >>> >> --Daniil
> > >>> >>
> > >>> >> *From: *JC Beyler<[email protected]>
> > >>> >> *Date: *Thursday, October 11, 2018 at 7:17
PM
> > >>> >> *To: *<[email protected]>
> > >>> >> *Cc: *<[email protected]>
> > >>> >> *Subject: *Re: RFR 8211736: jdb doesn't
print prompt when
> > >>> breakpoint
> > >>> >> is hit and suspend policy is
STOP_EVENT_THREAD
> > >>> >>
> > >>> >> Hi Daniil,
> > >>> >>
> > >>> >> Looks good to me. I saw a really small nit:
> > >>> >>
> > >>> >>
> > >>>
http://cr.openjdk.java.net/~dtitov/8211736/webrev.01/test/jdk/com/sun/jdi/JdbStopThreadTest.java.html
> > >>>
> > >>> >>
> > >>>
<http://cr.openjdk.java.net/%7Edtitov/8211736/webrev.01/test/jdk/com/sun/jdi/JdbStopThreadTest.java.html>
> > >>>
> > >>> >>
> > >>> >> 70 jdb.command(JdbCommand.stopThreadAt(
DEBUGGEE_CLASS
> > >>> ,bpLine));
> > >>> >>
> > >>> >> There is a space after the '('.
> > >>> >>
> > >>> >> No need to send a new webrev for that
evidently :),
> > >>> >>
> > >>> >> Jc
> > >>> >>
> > >>> >> On Thu, Oct 11, 2018 at 5:07 PM Daniil Titov
> > >>> >> <[email protected]
> > >>> <mailto:[email protected]>> wrote:
> > >>> >>
> > >>> >> Please review the change that fixes the
issue with
> > >>> missing prompt
> > >>> >> in jdb when a breakpoint is hit and the
suspend policy
> > >>> is set to
> > >>> >> stop the thread only.
> > >>> >>
> > >>> >> Webrev:
> > >>> http://cr.openjdk.java.net/~dtitov/8211736/webrev.01
> > >>> >>
<http://cr.openjdk.java.net/%7Edtitov/8211736/webrev.01>
> > >>> >> Issue:
https://bugs.openjdk.java.net/browse/JDK-8211736
> > >>> >>
> > >>> >> Thanks!
> > >>> >> --Daniil
> > >>> >>
> > >>> >>
> > >>> >>
> > >>> >> --
> > >>> >>
> > >>> >> Thanks,
> > >>> >>
> > >>> >> Jc
> > >>> >>
> > >>> >
> > >>>
> > >>>
> > >>
> > >>
> >
> >
> >
> >
> >
>
>
>
>
