Looks good to me
--alex
On 07/24/2018 16:23, Chris Plummer wrote:
Thanks, Serguei.
I could use one more reviewer.
thanks,
Chris
On 7/24/18 3:00 PM, serguei.spit...@oracle.com wrote:
Chris,
Thank you for the explanations.
I'm Okay with this webrev as it is.
Thanks,
Serguei
On 7/24/18 13:55, Chris Plummer wrote:
On 7/24/18 1:46 PM, serguei.spit...@oracle.com wrote:
http://cr.openjdk.java.net/~cjplummer/8151259/webrev.01/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass028.java.frames.html
- log.complain("Redefinition not started. Maybe running with -Xcomp.
Test ignored.");
+ log.complain("Redefinition not started. May need more time for
-Xcomp.");
+ status = Consts.TEST_FAILED;
return false;
}
. . .
- log.complain("Redefinition not completed.");
+ log.complain("Redefinition not completed. May need more time for
-Xcomp.");
+ status = Consts.TEST_FAILED;
+ return false; The complain is not fully correct if this can happen
not only with the -Xcomp. Could this message be relaxed a little bit?
I think it is relaxed. It says *may* need more time for -Xcomp. I'm
not sure how else to word it unless you want me to just say
"Redefinition not completed".
Also, just a side comment: The changes above are not that harmless.
As the status now is set to TEST_FAILED there is a potential for the
tests to start failing where they were passed before.
Yes, that was intentional. It's still the case that you only need the
fail = 0 change to fix the bug, but having these methods properly
cause the test to fail is necessary if something were to ever go
wrong and the redef was not started or completed. Otherwise the test
would either silently pass (if redef was not started) or just produce
error messages like it has been when it checks for the proper redef
(if the redef never completed).
thanks,
Chris
Otherwise, looks good.
Thanks,
Serguei
On 7/24/18 13:22, Chris Plummer wrote:
http://cr.openjdk.java.net/~cjplummer/8151259/webrev.01
Since I was removed the "else", there was no need for the "if", so
I removed it also. I had to re-indent the body of the "if" section
because of that. The webrev seems to not call out the whitespace
changes, although I also did a couple of other minor formatting
changes in the code that do show up.
Chris
On 7/24/18 12:42 PM, Chris Plummer wrote:
Yes. I'm just retesting first.
thanks,
Chris
On 7/24/18 12:18 PM, serguei.spit...@oracle.com wrote:
Hi Chris,
You have my all my comments and I leave it up to you to decide
what approach to pick.
Could you send an updated webrev, please?
Thanks,
Serguei
On 7/24/18 09:27, Chris Plummer wrote:
On 7/24/18 12:25 AM, serguei.spit...@oracle.com wrote:
Hi Chris,
I still feel, this fix adds more confusion and complexity.
Let's look at some fragments.
http://cr.openjdk.java.net/~cjplummer/8151259/webrev.00/test/hotspot/jtreg/vmTestbase/nsk/jvmti/RedefineClasses/redefclass028/redefclass028.c.frames.html
116 if ((strcmp(name, expHSMethod) == 0) &&
117 (strcmp(sig, expHSSignature) == 0)) {
118 NSK_DISPLAY0("CompiledMethodLoad: a tested hotspot method
found\n");
119
120 // CR 6604375: check whether "hot" method was entered
121 if (enteredHotMethod) {
122 hsMethodID = method;
123 fire = 1;
124 } else {
125 NSK_DISPLAY0("Compilation occured before method execution\n");
126 fire = 0; // Ignore this compilation. Wait for next one.
127 }
128 }
I think, the line #126 is not needed.
It just creates a confusion.
The fire == 0 from beginning.
Why do we need it to set to 0 again?
Yes, it can be removed. I just didn't give it much thought when
changing the code from -1 to 0.
Is it because it can be already set to 1?
Id so, I'm not sure I understand this code then.
187 } while(fire == 0);
188
189 NSK_DISPLAY0("agentProc: hotspot method compiled\n\n");
190
192 if (fire == 1) {
. . .
224 } else {
225 // fire == -1
226 // NOTE: This isn't suppose to happen anymore. Hot method
should always end up being entered.
227 NSK_COMPLAIN0("agentProc: \"hot\" method wasn't executed.
Don't perform redefinition\n");
228 }
I don't understand why do we need the check at the line #192.
The variable fire can be only equal to 0 or 1.
The only way out of the loop at the line #187 is if fire == 1.
Then the else statement at the lines 224-228 confuses even more.
The else section can be removed. I left it in as sort of an
assert, but I see now that it just cause confusion.
thanks,
Chris
On 7/23/18 20:19, Chris Plummer wrote:
On 7/23/18 5:22 PM, serguei.spit...@oracle.com wrote:
Hi Chris,
On 7/23/18 11:40, Chris Plummer wrote:
Hi Serguei,
If the fix was complicated I would agree, but it really just
boils down to this one line change:
- fire = -1;
+ fire = 0; // Ignore this compilation. Wait for
next one.
It is not obvious that this will completely fix the problem.
Is it possible that there will not be next compilation with
the -Xcomp?
It's only one method that we check for. I don't see why there
would be 2nd -Xcomp compilation for it, but even if there was,
the test will ignore it just like the first one. It will
ignore compilations of the method until the flag has been set
indicating the method has been executed once.
If for some reason the method is never compiled after being
executed once, the test will give up waiting for it (I think
after 30 seconds) and produce an error.
I'm afraid that it is what will always happen with the -Xcomp.
Then there is no point to waist this by waiting for timeout as
the test will successfully complete without testing anything.
It seems to be not worth this complexity.
I guess, you would want some extra tracing though. :)
Thanks,
Serguei
If it is possible then it is better to explicitly exclude
these tests for -Xcomp.
Otherwise, consider this reviewed.
Given that, I see no reason not to increase our test
coverage by supporting this test during -Xcomp runs.
I'd agree if it is going to be stable.
If problems turn up in the future, we can reconsider disabling
it.
thanks,
Chris
Thanks,
Serguei
thanks,
Chris
On 7/23/18 9:44 AM, serguei.spit...@oracle.com wrote:
Hi Chris,
Would it be more simple to avoid running these tests with
-Xcomp?
I guess, this would work: @requires vm.compMode != "Xcomp"
Thanks,
Serguei
On 7/23/18 00:42, Chris Plummer wrote:
Hello,
Please review the following fix for JDK11:
https://bugs.openjdk.java.net/browse/JDK-8151259
http://cr.openjdk.java.net/~cjplummer/8151259/webrev.00
It fixes the following 3 tests:
vmTestbase/nsk/jvmti/RedefineClasses/redefclass028.java
vmTestbase/nsk/jvmti/RedefineClasses/redefclass029.java
vmTestbase/nsk/jvmti/RedefineClasses/redefclass030.java
Any of which could fail when run with -Xcomp with
(followed by a bunch more errors):
# ERROR: Redefinition not started. Maybe running with
-Xcomp. Test ignored.
Although lately we've only seen this with
redefclass030.java on macosx.
These 3 tests do redefinition of a "hot" method after
triggering compilation for it. After the redef some
testing is done to ensure that the redef was done
correctly, but the issue these test have actually comes
before any redef is done.
The test attempts to trigger compilation by calling a hot
method a lot. The agent detects compilation by receiving a
CompiledMethodLoad event. There was an issue discovered
long ago that when -Xcomp is used, the compilation happens
before the "hot" method is ever called. Then the redef
would happen before compilation, and this somehow messed
up the test (I'm not exactly sure how). The fix was to
basically abandon the redef attempt when this problem is
detected, and then supposedly just let the test run to
completion (skipping the actual testing of the redef).
After this change, if you ran with -Xcomp it would pass,
but if you looked in the log you would see:
# ERROR: Redefinition not started. Maybe running with
-Xcomp. Test ignored.
However, there was a bug in the logic to make the test run
to completion, and also causes the above message to not
appear. Instead the test would fail with:
# ERROR: Redefinition not completed.
Followed by a bunch more error message during the part of
the test that checks if the redef was done properly.
If the CompiledMethodLoad event comes in before the hot
method is ever called (which it does with -Xcomp), the
test sets fire = -1. If the hot method was called, it is
set to 1. The setting of fire = -1 was added to fix the
-Xcomp problem mentioned above. The jvmti agent does the
following:
do {
THREAD_sleep(1);
/* wait for compilation to happen */
} while(fire == 0);
if (fire == 1) {
/* do the redef here */
NSK_DISPLAY0("agentProc: <<<<<<<<
RedefineClasses() is successfully done\n");
} else {
// fire == -1
NSK_DISPLAY0("agentProc: \"hot\" method wasn't
executed. Don't perform redefinition\n");
}
The agent then syncs with the debuggee, waiting for it
finish up. What the test expects is that
waitForRedefinitionStarted() in the debuggee will time out
after two seconds while waiting for fire == 1 (which it
thinks will will always happen because it was set to -1).
When it times out, the test does appear to exit properly
with, but with the following in the log, which is intended:
# ERROR: Redefinition not started. Maybe running with
-Xcomp. Test ignored.
However, sometimes before waitForRedefinitionStarted()
times out, the hot method is called enough times to
trigger compilation. So another CompiledMethodLoad event
arrives, and this time fire is set to 1. Because of this,
waitForRedefinitionStarted() doesn't time out and returns
with an indication that the redef has started. After this
waitForRedefinitionCompleted() is executed. It waits for
the redef to complete, but it never does since the agent
decided not to do the redef when it saw fire == -1. So
waitForRedefinitionCompleted() times out after 10 seconds
and the test fails, with:
# ERROR: Redefinition not completed.
Actually the above error is not really what causes the
failure. When the above error is detected, no error status
is set and the test continues as if the redef had been
done. So then the logic that detects if the redef was done
properly ends up failing, and that's where the test
actually indicates a failure status. You see a whole bunch
of other errors in the log because of all the checks that
fail.
The fix is to not abandon the test when the first
CompiledMethodLoad event is before the hot method was
called. Instead just leave fire==0 and wait for the next
CompiledMethodLoad event that is triggered after the
method is called enough times to be recompiled. I'm not
sure why it was not originally done this way. Possibly the
recompilation did not happen reliably, but I have not run
into this problem. The other changes in redefclass030.c
are just cleaning up debug tracing.
Another fix was to properly set the error status when
waitForRedefinitionStarted() or
waitForRedefinitionCompleted() times out, although this is
just a safety net and I didn't run into any cases where
this happened after fixing the CompiledMethodLoad event
handling. So in general the changes in redefclass030.java
were not needed, but provide better error handling.
thanks,
Chris
