See https://bugs.openjdk.java.net/browse/JDK-8173304 and also
https://bugs.openjdk.java.net/browse/JDK-4368399, which dates back to 2000.
Chris
On 11/15/18 8:40 PM, David Holmes wrote:
Hi Jc,
If I may put in my 2c ...
On 16/11/2018 2:13 pm, JC Beyler wrote:
Hi Richard,
Is this not a test that's failing due to a real bug? Ie: if someone
were to really be running the program in this configuration (with
printcompilation and printinlining) and attaching a debugger, would
they not reach the same issue?
This is just a limitation of connecting process streams via finite
pipes. If the pipe can fill before the target process reaches the
point where it communicates back to the initial process (which would
trigger the initial process to start draining the pipe) then you
effectively deadlock.
So you either structure the tests so that they work correctly with the
finite pipes provided by the test scaffold, or you modify the test
scaffold to either provide a bigger pipe or else rework it to ensure
pipes can't fill and cause indefinite blocking.
For the case at hand fixing the test to not be so verbose is
reasonable in my opinion, though I'm not sure I'd remove Xcomp
altogether as Xcomp likes a range of programs to put it through its
paces.
But it wouldn't be unreasonable to file a RFE to make the TestScaffold
handle this better.
Cheers,
David
Should that not be fixed in some way instead? Or is this such an
improbable case that we just consider it ludicrous?
Thanks,
Jc
On Thu, Nov 15, 2018 at 2:32 PM Reingruber, Richard
<richard.reingru...@sap.com <mailto:richard.reingru...@sap.com>> wrote:
Hi,
could I please get reviews for the following small patch? It fixes a
bug in the test
com/sun/jdi/SetLocalWhileThreadInNative.java that causes a deadlock
when executed with
-vmoption:-Xcomp.
Deadlock:
Debuggee (SetLocalWhileThreadInNativeTarget):
- running with -Xcomp
- still in early start-up
- printed a lot on tty already, because -XX:+PrintCompilation
-XX:+PrintInlining are given
- java thread waits for compiler thread to finish compile task
- compiler thread is blocked in write on tty. tty buffer is full,
because debugger is not yet
reading debuggee's output
Debugger
- waiting until connection to debugger is established
The fix is to remove -XX:+PrintCompilation -XX:+PrintInlining. In
addition it excludes the test if
running with -Xcomp, because that mode does not add a lot of value,
as the test actually only needs
dontinline_testMethod() to be compiled. Running with -Xcomp just
wastes energy.
Webrev:
http://cr.openjdk.java.net/~rrich/webrevs/2018/8213902/webrev.01/
Bug: https://bugs.openjdk.java.net/browse/JDK-8213902
The contribution needs to be sponsored as well, please.
Thanks, Richard.
--
Thanks,
Jc
