RFR 8242263: Diagnose synchronization on primitive wrappers
Patricio Chilano
patricio.chilano.mateo at oracle.com
Mon Aug 10 13:44:53 UTC 2020
Hi Coleen,
On 8/7/20 12:58 PM, Coleen Phillimore wrote:
>
>
> On 8/7/20 11:49 AM, Patricio Chilano wrote:
>> Hi Coleen,
>>
>> On 8/7/20 10:53 AM, Coleen Phillimore wrote:
>>>
>>>
>>> On 8/6/20 9:45 PM, Patricio Chilano wrote:
>>>> Hi Coleen,
>>>>
>>>> Thanks for looking at this.
>>>>
>>>> On 8/6/20 7:17 PM, Coleen Phillimore wrote:
>>>>>
>>>>> Patricio, One question:
>>>>>
>>>>> http://cr.openjdk.java.net/~pchilanomate/8242263/v3/webrev/src/hotspot/share/runtime/synchronizer.cpp.udiff.html
>>>>>
>>>>>
>>>>> + // adjust bcp to point back to monitorenter so that we print the
>>>>> correct line numbers
>>>>>
>>>>>
>>>>> How do the fatal and event print the correct line numbers here? I
>>>>> see the logging gets it from the stack trace. Should the abort
>>>>> message have more information in it? You can get the source and
>>>>> line number information in the same way that print_stack_on() gets
>>>>> it.
>>>> For the fatal error case I'm not printing line numbers as I do with
>>>> the warning case or as you get with JFR events. But maybe I should
>>>> print the stack too and then exit the VM. You can get the stack
>>>> info and the line number of the monitorenter bytecode that caused
>>>> the crash from the generated hs_err file though.
>>>
>>> Can you send a sample, please?
>> At the top of the hs_err you will get:
>>
>> #
>> # A fatal error has been detected by the Java Runtime Environment:
>> #
>> # Internal Error
>> (/xx/xxx/xxxx/open/src/hotspot/share/runtime/synchronizer.cpp:574),
>> pid=48810, tid=48811
>> # fatal error: Synchronizing on object 0x00000007ff0758a8 of klass
>> java.lang.Integer
>> #
>>
>> And then on the stacktrace you can see:
>>
>> Stack: [0x00007f982b6ce000,0x00007f982b7cf000],
>> sp=0x00007f982b7cd5c0, free space=1021k
>> Native frames: (J=compiled Java code, A=aot compiled Java code,
>> j=interpreted, Vv=VM code, C=native code)
>> V [libjvm.so+0x1662385]
>> ObjectSynchronizer::handle_sync_on_primitive_wrapper(Handle,
>> Thread*)+0x185
>> V [libjvm.so+0x16683ac] ObjectSynchronizer::enter(Handle,
>> BasicLock*, Thread*)+0x21c
>> V [libjvm.so+0xce88fa] InterpreterRuntime::monitorenter(JavaThread*,
>> BasicObjectLock*)+0x13a
>> j SimpleTest.main([Ljava/lang/String;)V+24
>> v ~StubRoutines::call_stub
>> V [libjvm.so+0xd0263a] JavaCalls::call_helper(JavaValue*,
>> methodHandle const&, JavaCallArguments*, Thread*)+0x62a
>> V [libjvm.so+0xe22c8e] jni_invoke_static(JNIEnv_*, JavaValue*,
>> _jobject*, JNICallType, _jmethodID*, JNI_ArgumentPusher*, Thr
>> .constprop.1]+0x35e
>> V [libjvm.so+0xe28e6b] jni_CallStaticVoidMethod+0x21b
>> C [libjli.so+0x496e] JavaMain+0xc1e
>> C [libjli.so+0x7759] ThreadJavaMain+0x9
>>
>> Java frames: (J=compiled Java code, j=interpreted, Vv=VM code)
>> j SimpleTest.main([Ljava/lang/String;)V+24
>> v ~StubRoutines::call_stub
>>
>> Where +24 is the bci. But that would be with the interpreter, with c1
>> that line will show as:
>>
>> J 576 c1 SimpleTest.main([Ljava/lang/String;)V (205 bytes) @
>> 0x00007f97b5ae5dc7
>>
>> You have the method where it failed but not the exact bci. So maybe I
>> should print the stack and then exit the VM.
>>
>>> I guess there isn't a handy function to show the source file name
>>> and line number in the fatal error message.
>> I'll see if there is an easy way to have it in the fatal error
>> message otherwise I can just print the stack as with the warning case
>> and exit.
>
> I don't know if we want the fatal message to print the whole stack.
> But an improvement would be:
>
> # fatal error: Synchronizing on object 0x00000007ff0758a8 of klass
> java.lang.Integer in method->external_name()+bci
>
> which you have in the function and then people won't have to go to the
> hs_err file.
I tested two different changes. The first one gets the method and bci
and adds it to the fatal error message as you said:
diff --git a/src/hotspot/share/runtime/synchronizer.cpp
b/src/hotspot/share/runtime/synchronizer.cpp
--- a/src/hotspot/share/runtime/synchronizer.cpp
+++ b/src/hotspot/share/runtime/synchronizer.cpp
@@ -572,5 +572,9 @@
if (DiagnoseSyncOnPrimitiveWrappers == FATAL_EXIT) {
ResourceMark rm(self);
- fatal("Synchronizing on object " INTPTR_FORMAT " of klass %s",
p2i(obj()), obj->klass()->external_name());
+ vframeStream vfst(self);
+ Method* method = vfst.method();
+ int bci = vfst.bci();
+ fatal("Synchronizing on object " INTPTR_FORMAT " of klass %s in
\"%s\" at bci:%d",
+ p2i(obj()), obj->klass()->external_name(), method ?
method->external_name() : "", bci);
}
Which produces the following output:
# Internal Error
(/scratch/pchilano/random7/open/src/hotspot/share/runtime/synchronizer.cpp:577),
pid=13759, tid=13785
# fatal error: Synchronizing on object 0x00000001013d72d8 of klass
java.lang.Float in "void SimpleTest.run()" at bci:24
#
In the second one I use the same print_stack_on() method I use for the
warning case but print on a stringStream object instead, and then I
print the first line of the buffer only.
diff --git a/src/hotspot/share/runtime/synchronizer.cpp
b/src/hotspot/share/runtime/synchronizer.cpp
--- a/src/hotspot/share/runtime/synchronizer.cpp
+++ b/src/hotspot/share/runtime/synchronizer.cpp
@@ -572,5 +572,12 @@
if (DiagnoseSyncOnPrimitiveWrappers == FATAL_EXIT) {
ResourceMark rm(self);
- fatal("Synchronizing on object " INTPTR_FORMAT " of klass %s",
p2i(obj()), obj->klass()->external_name());
+ stringStream ss;
+ self->print_stack_on(&ss);
+ char* base = (char*)strstr(ss.base(), "at");
+ char* newline = (char*)strchr(ss.base(), '\n');
+ if (newline != NULL) {
+ *newline = '\0';
+ }
+ fatal("Synchronizing on object " INTPTR_FORMAT " of klass %s %s",
p2i(obj()), obj->klass()->external_name(), base);
}
Which produces the following output:
# Internal Error
(/scratch/pchilano/random7/open/src/hotspot/share/runtime/synchronizer.cpp:581),
pid=9288, tid=9306
# fatal error: Synchronizing on object 0x00000001013d72d8 of klass
java.lang.Float at SimpleTest.run(SimpleTest.java:70)
#
I think the second method is better since it provides the actual file
and line number, what do you think?
Thanks,
Patricio
> Thanks,
> Coleen
>
>
>>
>>
>> Thanks,
>> Patricio
>>> Thanks,
>>> Coleen
>>>>
>>>> I don't know which exact technique JFR uses to print line numbers
>>>> but it has to include reading the current bcp. Since when coming
>>>> from the interpreter for monitorenter the bcp is always already
>>>> pointing to the next instruction we need to decrement it to print
>>>> the correct line numbers. I tested it and if I don't fix the bcp,
>>>> as expected JFR too will print the next line number for the top frame.
>>>>
>>>>
>>>> Patricio
>>>>> Otherwise, this looks good to me.
>>>>> Coleen
>>>>>
>>>>>
>>>>> On 8/6/20 2:48 PM, Patricio Chilano wrote:
>>>>>> Hi Dan,
>>>>>>
>>>>>> On 8/5/20 6:47 PM, Daniel D. Daugherty wrote:
>>>>>>> I'm peeking ahead to the next webrev... :-)
>>>>>>>
>>>>>>> > http://cr.openjdk.java.net/~pchilanomate/8242263/v3/webrev/
>>>>>> : )
>>>>>>
>>>>>>> General comments:
>>>>>>> - check files for copyright year updates.
>>>>>> Updated accessFlags.hpp, c1_MacroAssembler_aarch64.cpp,
>>>>>> c1_MacroAssembler_arm.cpp and c1_MacroAssembler_x86.cpp.
>>>>>>
>>>>>>> src/hotspot/share/runtime/synchronizer.hpp
>>>>>>> No comments.
>>>>>>>
>>>>>>> src/hotspot/share/runtime/synchronizer.cpp
>>>>>>> L507: const markWord mark = obj->mark();
>>>>>>> L508:
>>>>>>> L509: if (DiagnoseSyncOnPrimitiveWrappers != 0 &&
>>>>>>> obj->klass()->is_box()) {
>>>>>>> L510: return false;
>>>>>>> L511: }
>>>>>>> The new bailout on L509-511 can move above L507.
>>>>>> Moved.
>>>>>>
>>>>>>> L573: fatal("Synchronizing on object " INTPTR_FORMAT " of
>>>>>>> klass %s", p2i(obj()), obj->klass()->external_name());
>>>>>>> This external_name() call does not have a ResourceMark.
>>>>>> Good catch! I had one in a previous version but then I changed
>>>>>> the conditionals and lost it for the fatal error case. The test
>>>>>> worked okay because for the main JavaThread there is a
>>>>>> ResourceMark in jni_invoke_static() (jni.cpp).
>>>>>>
>>>>>>> src/hotspot/share/logging/logTag.hpp
>>>>>>> No comments.
>>>>>>>
>>>>>>> src/hotspot/share/oops/klass.hpp
>>>>>>> No comments.
>>>>>>>
>>>>>>> src/hotspot/share/utilities/accessFlags.hpp
>>>>>>> No comments.
>>>>>>>
>>>>>>> src/hotspot/share/runtime/globals.hpp
>>>>>>> L814: "0: off "
>>>>>>> Missing a ';' after "off".
>>>>>> Fixed.
>>>>>>
>>>>>>> L816: "2: log message to stdout.
>>>>>>> Perhaps add "(by default)" after "stdout" or
>>>>>>> don't say where log output is at all.
>>>>>>>
>>>>>>> src/hotspot/share/runtime/arguments.cpp
>>>>>>> L4197: LogConfiguration::configure_stdout(LogLevel::Info,
>>>>>>> true, LOG_TAGS(primitivewrappers));
>>>>>>> Hmmm... maybe ignore my comments about L816 in globals.hpp
>>>>>>> since it looks like logging output is configured to
>>>>>>> 'stdout'.
>>>>>>> I'm assuming that other log options to put output elsewhere
>>>>>>> are overridden by this code?
>>>>>> Right. So the logging is done under UL with the tag
>>>>>> primitivewrappers. If that tag is specified in Xlog then this
>>>>>> conditional will be skipped because !log_is_enabled(Info,
>>>>>> primitivewrappers) will be false.
>>>>>>
>>>>>>> src/hotspot/share/classfile/systemDictionary.cpp
>>>>>>> L2188: for (int i = T_BOOLEAN; i < T_LONG+1; i++) {
>>>>>>> nit - s/T_LONG+1/T_LONG + 1/
>>>>>> Fixed.
>>>>>>
>>>>>>> L2191:
>>>>>>> _box_klasses[i]->set_prototype_header(markWord::prototype());
>>>>>>> I assume we're keeping the prototype_header field when
>>>>>>> Biased Locking
>>>>>>> goes away? The reason I ask:
>>>>>>>
>>>>>>> static markWord prototype() {
>>>>>>> return markWord( no_hash_in_place | no_lock_in_place );
>>>>>>> }
>>>>>>>
>>>>>>> is because without Biased Locking, do we really need the
>>>>>>> prototype
>>>>>>> anymore? The initial markWord won't need possible
>>>>>>> variants...
>>>>>> Yes, I think it can go away unless somebody finds another use for
>>>>>> it. Maybe Valhalla.
>>>>>>
>>>>>>> src/hotspot/share/jfr/metadata/metadata.xml
>>>>>>> L69: <Event name="SyncOnPrimitiveWrapper" category="Java
>>>>>>> Application"
>>>>>>> Is the category "Java Application" because it's the
>>>>>>> application
>>>>>>> code that did something "wrong" here? Where
>>>>>>> "application" is loosely
>>>>>>> defined to include the possibility of auto generated
>>>>>>> code, library
>>>>>>> code and the like? Or perhaps "application" because
>>>>>>> something "above"
>>>>>>> the "Java Virtual Machine, Runtime" did the "wrong"
>>>>>>> thing here?
>>>>>> I don't know what the right category should be really. I saw the
>>>>>> events JavaMonitorEnter, JavaMonitorWait and JavaMonitorInflate
>>>>>> and thought this event should fall in the same category they do.
>>>>>>
>>>>>>> src/jdk.jfr/share/conf/jfr/default.jfc
>>>>>>> No comments.
>>>>>>>
>>>>>>> src/jdk.jfr/share/conf/jfr/profile.jfc
>>>>>>> No comments.
>>>>>>>
>>>>>>> test/lib/jdk/test/lib/jfr/EventNames.java
>>>>>>> No comments.
>>>>>>>
>>>>>>> src/hotspot/cpu/aarch64/aarch64.ad
>>>>>>> L3517: __ tbnz(tmp, exact_log2(JVM_ACC_IS_BOX_CLASS),
>>>>>>> cont);
>>>>>>> <snip>
>>>>>>> L3578: __ bind(cont);
>>>>>>> L3579: // flag == EQ indicates success
>>>>>>> L3580: // flag == NE indicates failure
>>>>>>> If tbnz() branches to "cont" when we have a box class,
>>>>>>> what's
>>>>>>> the flag value set to (EQ or NE)? And what set that flag
>>>>>>> value?
>>>>>>> The reason I ask is I don't think tbnz() sets condition
>>>>>>> codes...
>>>>>> Right, it doesn't set condition codes, so I kept the version I
>>>>>> had (more on that below).
>>>>>>
>>>>>>> src/hotspot/cpu/aarch64/c1_MacroAssembler_aarch64.cpp
>>>>>>> No comments.
>>>>>>>
>>>>>>> src/hotspot/cpu/aarch64/interp_masm_aarch64.cpp
>>>>>>> No comments.
>>>>>>>
>>>>>>> src/hotspot/cpu/aarch64/macroAssembler_aarch64.cpp
>>>>>>> int MacroAssembler::biased_locking_enter(Register lock_reg,
>>>>>>> Register obj_reg,
>>>>>>> Register swap_reg,
>>>>>>> Register tmp_reg,
>>>>>>> bool
>>>>>>> swap_reg_contains_mark,
>>>>>>> Label& done,
>>>>>>> Label* slow_case,
>>>>>>> BiasedLockingCounters* counters) {
>>>>>>> I think you've changed the only callers of
>>>>>>> biased_locking_enter()
>>>>>>> that cared about the return value with this changeset so
>>>>>>> it can
>>>>>>> be changed to a void function.
>>>>>> Ok, this is what I mentioned to David in a previous email. Done.
>>>>>>
>>>>>>> src/hotspot/cpu/arm/c1_MacroAssembler_arm.cpp
>>>>>>> No comments.
>>>>>>>
>>>>>>> src/hotspot/cpu/arm/c2_MacroAssembler_arm.cpp
>>>>>>> L96: tbnz(Rscratch, exact_log2(JVM_ACC_IS_BOX_CLASS),
>>>>>>> done);
>>>>>>> <snip>
>>>>>>> L131: bind(done);
>>>>>>> L132:
>>>>>>> L133: // At this point flags are set as follows:
>>>>>>> L134: // EQ -> Success
>>>>>>> L135: // NE -> Failure, branch to slow path
>>>>>>> If tbnz() branches to "done" when we have a box class,
>>>>>>> what's
>>>>>>> the flag value set to (EQ or NE)? And what set that flag
>>>>>>> value?
>>>>>>> The reason I ask is I don't think tbnz() sets condition
>>>>>>> codes...
>>>>>> Right. Same as above, I kept the version I had.
>>>>>>
>>>>>>> src/hotspot/cpu/arm/interp_masm_arm.cpp
>>>>>>> No comments.
>>>>>>>
>>>>>>> src/hotspot/cpu/arm/macroAssembler_arm.cpp
>>>>>>> int MacroAssembler::biased_locking_enter(Register obj_reg,
>>>>>>> Register swap_reg, Register tmp_reg,
>>>>>>> bool
>>>>>>> swap_reg_contains_mark,
>>>>>>> Register tmp2,
>>>>>>> Label& done, Label& slow_case,
>>>>>>> BiasedLockingCounters* counters) {
>>>>>>> I think you've changed the only callers of
>>>>>>> biased_locking_enter()
>>>>>>> that cared about the return value with this changeset so
>>>>>>> it can
>>>>>>> be changed to a void function.
>>>>>> Done.
>>>>>>
>>>>>>> src/hotspot/cpu/ppc/c1_MacroAssembler_ppc.cpp
>>>>>>> src/hotspot/cpu/ppc/interp_masm_ppc_64.cpp
>>>>>>> src/hotspot/cpu/ppc/macroAssembler_ppc.cpp
>>>>>>> No comments on the PPC code.
>>>>>>>
>>>>>>> src/hotspot/cpu/s390/c1_MacroAssembler_s390.cpp
>>>>>>> src/hotspot/cpu/s390/interp_masm_s390.cpp
>>>>>>> src/hotspot/cpu/s390/macroAssembler_s390.cpp
>>>>>>> No comments on the S390 code.
>>>>>>>
>>>>>>> src/hotspot/cpu/x86/c1_MacroAssembler_x86.cpp
>>>>>>> L58: load_klass(hdr, obj, rklass_decode_tmp);
>>>>>>> What will this do with a 'noreg' value? (I need a
>>>>>>> refresher.)
>>>>>> When not in 64 bit mode that register just won't be used.
>>>>>>
>>>>>>> src/hotspot/cpu/x86/c2_MacroAssembler_x86.cpp
>>>>>>> No comments.
>>>>>>>
>>>>>>> src/hotspot/cpu/x86/interp_masm_x86.cpp
>>>>>>> No comments.
>>>>>>>
>>>>>>> src/hotspot/cpu/x86/macroAssembler_x86.cpp
>>>>>>> int MacroAssembler::biased_locking_enter(Register lock_reg,
>>>>>>> Register obj_reg,
>>>>>>> Register swap_reg,
>>>>>>> Register tmp_reg,
>>>>>>> Register tmp_reg2,
>>>>>>> bool
>>>>>>> swap_reg_contains_mark,
>>>>>>> Label& done,
>>>>>>> Label* slow_case,
>>>>>>> BiasedLockingCounters* counters) {
>>>>>>> I think you've changed the only caller of
>>>>>>> biased_locking_enter()
>>>>>>> that cared about the return value with this changeset so
>>>>>>> it can
>>>>>>> be changed to a void function.
>>>>>> Done.
>>>>>>
>>>>>>> test/hotspot/jtreg/runtime/Monitor/SyncOnPrimitiveWrapperTest.java
>>>>>>> L30: * @test SyncOnPrimitiveWrapperTest
>>>>>>> No parameter to @test directive.
>>>>>> Removed.
>>>>>>
>>>>>>> L136: private static long sharedCounter = 0L;
>>>>>>> Since you don't do anything with sharedCounter other
>>>>>>> than increment it,
>>>>>>> can the compilers optimize it away? If it can be
>>>>>>> optimized away, does
>>>>>>> that mean that:
>>>>>>>
>>>>>>> L142: synchronized (obj) {
>>>>>>>
>>>>>>> can also be optimized away?
>>>>>>>
>>>>>>> I don't think that:
>>>>>>>
>>>>>>> L161: synchronized (sharedLock1) {
>>>>>>>
>>>>>>> can be optimized away because it is shared by multiple
>>>>>>> threads.
>>>>>>>
>>>>>>> test/jdk/jdk/jfr/event/runtime/TestSyncOnPrimitiveWrapperEvent.java
>>>>>>> Similar questions about 'counter' being optimized away.
>>>>>>> Similar question about "synchronized (obj) {" being
>>>>>>> optimized away.
>>>>>> I'm not sure if the compiler will optimize it away. Seems
>>>>>> unlikely given the counter we are incrementing is not just local
>>>>>> to some thread.
>>>>>>
>>>>>>
>>>>>> Ok, below is v3 which has the following changes:
>>>>>> - Use a 32 bit load for the _access_flags field, instead of 64
>>>>>> - Martin's implementation for s390 and fix for PPC
>>>>>> - Faster LogTest version
>>>>>> - Above changes based on Dan review
>>>>>>
>>>>>> I'm retesting in mach5 tiers1-6 (which tests x64 and aarch64
>>>>>> only) again with -XX:DiagnoseSyncOnPrimitiveWrappers=2. I checked
>>>>>> it builds in arm32, ppc and s390.
>>>>>>
>>>>>> Full: http://cr.openjdk.java.net/~pchilanomate/8242263/v3/webrev
>>>>>> Inc: http://cr.openjdk.java.net/~pchilanomate/8242263/v3/inc/webrev
>>>>>>
>>>>>>
>>>>>> @Martin:
>>>>>> Please check if the test doesn't timeout for you now with the
>>>>>> changes I made to LogTest.
>>>>>> Also, I tried to use tbnz in aarch64 and arm32 instead of tst +
>>>>>> br (except for c2 since we actually need to set the condition
>>>>>> flags), but for c1 I was getting an assertion in the compiler
>>>>>> thread:
>>>>>>
>>>>>> guarantee(chk == -1 || chk == 0) failed: Field too big for insn
>>>>>>
>>>>>> This is the stack when that happens:
>>>>>>
>>>>>> MacroAssembler::pd_patch_instruction_size(unsigned char*,
>>>>>> unsigned char*)+0x398
>>>>>> AbstractAssembler::bind(Label&)+0x118
>>>>>> MonitorEnterStub::emit_code(LIR_Assembler*)+0x28
>>>>>> LIR_Assembler::emit_slow_case_stubs()+0x54
>>>>>> Compilation::emit_code_body()+0x17c
>>>>>>
>>>>>> The change was simply:
>>>>>>
>>>>>> diff --git
>>>>>> a/src/hotspot/cpu/aarch64/c1_MacroAssembler_aarch64.cpp
>>>>>> b/src/hotspot/cpu/aarch64/c1_MacroAssembler_aarch64.cpp
>>>>>> --- a/src/hotspot/cpu/aarch64/c1_MacroAssembler_aarch64.cpp
>>>>>> +++ b/src/hotspot/cpu/aarch64/c1_MacroAssembler_aarch64.cpp
>>>>>> @@ -78,7 +78,6 @@
>>>>>> if (DiagnoseSyncOnPrimitiveWrappers != 0) {
>>>>>> load_klass(hdr, obj);
>>>>>> - ldr(hdr, Address(hdr, Klass::access_flags_offset()));
>>>>>> - tst(hdr, JVM_ACC_IS_BOX_CLASS);
>>>>>> - br(Assembler::NE, slow_case);
>>>>>> + ldrw(hdr, Address(hdr, Klass::access_flags_offset()));
>>>>>> + tbnz(hdr, exact_log2(JVM_ACC_IS_BOX_CLASS), slow_case);
>>>>>> }
>>>>>>
>>>>>> So the issue must be related to where we want to jump.
>>>>>>
>>>>>> Thanks,
>>>>>> Patricio
>>>>>>> Dan
>>>>>>>
>>>>>>>
>>>>>>> On 8/5/20 9:01 AM, Patricio Chilano wrote:
>>>>>>>> Hi Martin,
>>>>>>>>
>>>>>>>> On 8/5/20 4:47 AM, Doerr, Martin wrote:
>>>>>>>>> Hi Patricio,
>>>>>>>>>
>>>>>>>>> using 8 Byte load instructions for jint fields is a terrible
>>>>>>>>> coding style!
>>>>>>>>> Someone else may see it and use an 8 Byte store. Will result
>>>>>>>>> in great fun for debugging!
>>>>>>>>>
>>>>>>>>> And on Big Endian you will simply access the wrong bits.
>>>>>>>> Ah, of course! Those 32 bits will be in the wrong place when
>>>>>>>> doing the test.
>>>>>>>>
>>>>>>>>> Note that Big Endian Platforms are AIX, old linux ppc, s390,
>>>>>>>>> SPARC. I don't think you have tested on them.
>>>>>>>>>
>>>>>>>>>> We could remove the nested synchronized statements in the
>>>>>>>>>> run() method
>>>>>>>>>> so that we don't generate that much logging. We could also lower
>>>>>>>>>> LOOP_COUNT. I think the issue is also because we are running
>>>>>>>>>> LogTest
>>>>>>>>>> with multiple flag combinations. Not sure what we should
>>>>>>>>>> touch first.
>>>>>>>>>> Maybe the synchronized statements, have only one or two and
>>>>>>>>>> test that
>>>>>>>>>> first?
>>>>>>>>> Sounds like helpful ideas. Please go ahead and strip things down.
>>>>>>>> Great, I will send v3 later with those changes.
>>>>>>>>
>>>>>>>> Thanks Martin!
>>>>>>>>
>>>>>>>> Patricio
>>>>>>>>> Thanks for taking care of it.
>>>>>>>>>
>>>>>>>>> Best regards,
>>>>>>>>> Martin
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>> -----Original Message-----
>>>>>>>>>> From: Patricio Chilano <patricio.chilano.mateo at oracle.com>
>>>>>>>>>> Sent: Dienstag, 4. August 2020 20:26
>>>>>>>>>> To: Doerr, Martin <martin.doerr at sap.com>; David Holmes
>>>>>>>>>> <david.holmes at oracle.com>; hotspot-runtime-dev at openjdk.java.net;
>>>>>>>>>> hotspot-jfr-dev at openjdk.java.net
>>>>>>>>>> Subject: Re: RFR 8242263: Diagnose synchronization on
>>>>>>>>>> primitive wrappers
>>>>>>>>>>
>>>>>>>>>> Hi Martin,
>>>>>>>>>>
>>>>>>>>>> On 8/4/20 1:35 PM, Doerr, Martin wrote:
>>>>>>>>>>> Hi Patricio,
>>>>>>>>>>>
>>>>>>>>>>>> Ok, I'll change it to movl + testl and test it out before
>>>>>>>>>>>> sending v3.
>>>>>>>>>>> Thanks. I forgot to mention arm + aarch64.
>>>>>>>>>>> Aarch64 uses ldrw + tbnz.
>>>>>>>>>>> Arm 32 bit uses ldr_u32 + tbnz.
>>>>>>>>>>>
>>>>>>>>>>> I remember having seen the same mistake ��
>>>>>>>>>>> And nobody noticed it on little Endian platforms.
>>>>>>>>>> Ok, I can use a tbnz instead of test and then a branch on
>>>>>>>>>> arm32 and aarch64.
>>>>>>>>>> Shouldn't a normal ldr in arm32 work fine?
>>>>>>>>>> Also in 64 bits (either x64 or aarch64) I don't see the issue
>>>>>>>>>> of using a
>>>>>>>>>> 64 bit load, besides the fact that we only care about the
>>>>>>>>>> first 32 bits.
>>>>>>>>>> Regardless of the endianness, aren't we masking out the upper
>>>>>>>>>> part when
>>>>>>>>>> we do AND/TEST or if we test a bit in the 0-31 bit range?
>>>>>>>>>> Otherwise it
>>>>>>>>>> seems it should have failed for one of those platforms in my
>>>>>>>>>> tests.
>>>>>>>>>>
>>>>>>>>>>>> I see that some tests use @run driver/timeout=xxxx. Maybe
>>>>>>>>>>>> you can
>>>>>>>>>>>> specify that and see if that fixes it? Let me know if that
>>>>>>>>>>>> works and I
>>>>>>>>>>>> can add it to the test.
>>>>>>>>>>> That seems to have an effect. But now I'm not patient enough
>>>>>>>>>>> to wait for
>>>>>>>>>> the test to finish.
>>>>>>>>>>> Maybe the problem is that I'm using slow debug builds.
>>>>>>>>>>> But is there a chance to make the test quicker without
>>>>>>>>>>> losing coverage
>>>>>>>>>> significantly?
>>>>>>>>>>> I think the test is too slow this way to run it on a regular
>>>>>>>>>>> basis. We'd need to
>>>>>>>>>> spend dedicated machines for it.
>>>>>>>>>> We could remove the nested synchronized statements in the
>>>>>>>>>> run() method
>>>>>>>>>> so that we don't generate that much logging. We could also lower
>>>>>>>>>> LOOP_COUNT. I think the issue is also because we are running
>>>>>>>>>> LogTest
>>>>>>>>>> with multiple flag combinations. Not sure what we should
>>>>>>>>>> touch first.
>>>>>>>>>> Maybe the synchronized statements, have only one or two and
>>>>>>>>>> test that
>>>>>>>>>> first?
>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>> Thanks,
>>>>>>>>>> Patricio
>>>>>>>>>>> Best regards,
>>>>>>>>>>> Martin
>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>>> -----Original Message-----
>>>>>>>>>>>> From: Patricio Chilano <patricio.chilano.mateo at oracle.com>
>>>>>>>>>>>> Sent: Dienstag, 4. August 2020 17:47
>>>>>>>>>>>> To: Doerr, Martin <martin.doerr at sap.com>; David Holmes
>>>>>>>>>>>> <david.holmes at oracle.com>;
>>>>>>>>>>>> hotspot-runtime-dev at openjdk.java.net;
>>>>>>>>>>>> hotspot-jfr-dev at openjdk.java.net
>>>>>>>>>>>> Subject: Re: RFR 8242263: Diagnose synchronization on
>>>>>>>>>>>> primitive wrappers
>>>>>>>>>>>>
>>>>>>>>>>>> Hi Martin,
>>>>>>>>>>>>
>>>>>>>>>>>> Thanks for fixing PPC and taking care of s390!
>>>>>>>>>>>>
>>>>>>>>>>>> On 8/4/20 11:18 AM, Doerr, Martin wrote:
>>>>>>>>>>>>> Hi Patricio,
>>>>>>>>>>>>>
>>>>>>>>>>>>> I suggest to use movl + testl for checking the access flag
>>>>>>>>>>>>> as for other
>>>>>>>>>> access
>>>>>>>>>>>> flags on x64.
>>>>>>>>>>>> Ok, I'll change it to movl + testl and test it out before
>>>>>>>>>>>> sending v3.
>>>>>>>>>>>>
>>>>>>>>>>>>> New version for PPC64 and s390 see below.
>>>>>>>>>>>>>
>>>>>>>>>>>>> The test SyncOnPrimitiveWrapperTest produces hs_err files as
>>>>>>>>>> expected.
>>>>>>>>>>>> However, I'm getting timeout issues:
>>>>>>>>>>>>> timed out (timeout set to 120000ms, elapsed time including
>>>>>>>>>>>>> timeout
>>>>>>>>>>>> handling was 122372ms)
>>>>>>>>>>>>> Can we provide more time?
>>>>>>>>>>>> I see that some tests use @run driver/timeout=xxxx. Maybe
>>>>>>>>>>>> you can
>>>>>>>>>>>> specify that and see if that fixes it? Let me know if that
>>>>>>>>>>>> works and I
>>>>>>>>>>>> can add it to the test.
>>>>>>>>>>>>
>>>>>>>>>>>> Thanks,
>>>>>>>>>>>> Patricio
>>>>>>>>>>>>> Best regards,
>>>>>>>>>>>>> Martin
>>>>>>>>>>>>>
>>>>>>>>>>>>>
>>>>>>>>>>>>> diff -r 77852e129401
>>>>>>>>>>>>> src/hotspot/cpu/ppc/c1_MacroAssembler_ppc.cpp
>>>>>>>>>>>>> --- a/src/hotspot/cpu/ppc/c1_MacroAssembler_ppc.cpp Tue
>>>>>>>>>>>>> Aug 04
>>>>>>>>>>>> 10:03:57 2020 +0200
>>>>>>>>>>>>> +++ b/src/hotspot/cpu/ppc/c1_MacroAssembler_ppc.cpp Tue
>>>>>>>>>>>>> Aug 04
>>>>>>>>>>>> 16:04:31 2020 +0200
>>>>>>>>>>>>> @@ -107,8 +107,8 @@
>>>>>>>>>>>>>
>>>>>>>>>>>>> if (DiagnoseSyncOnPrimitiveWrappers != 0) {
>>>>>>>>>>>>> load_klass(Rscratch, Roop);
>>>>>>>>>>>>> - ld(Rscratch, in_bytes(Klass::access_flags_offset()),
>>>>>>>>>>>>> Rscratch);
>>>>>>>>>>>>> - andi(Rscratch, Rscratch, JVM_ACC_IS_BOX_CLASS);
>>>>>>>>>>>>> + lwz(Rscratch, in_bytes(Klass::access_flags_offset()),
>>>>>>>>>>>>> Rscratch);
>>>>>>>>>>>>> + testbitdi(CCR0, R0, Rscratch,
>>>>>>>>>>>>> exact_log2(JVM_ACC_IS_BOX_CLASS));
>>>>>>>>>>>>> bne(CCR0, slow_case);
>>>>>>>>>>>>> }
>>>>>>>>>>>>>
>>>>>>>>>>>>> diff -r 77852e129401
>>>>>>>>>>>>> src/hotspot/cpu/ppc/interp_masm_ppc_64.cpp
>>>>>>>>>>>>> --- a/src/hotspot/cpu/ppc/interp_masm_ppc_64.cpp Tue Aug 04
>>>>>>>>>>>> 10:03:57 2020 +0200
>>>>>>>>>>>>> +++ b/src/hotspot/cpu/ppc/interp_masm_ppc_64.cpp Tue Aug 04
>>>>>>>>>>>> 16:04:31 2020 +0200
>>>>>>>>>>>>> @@ -912,8 +912,8 @@
>>>>>>>>>>>>>
>>>>>>>>>>>>> if (DiagnoseSyncOnPrimitiveWrappers != 0) {
>>>>>>>>>>>>> load_klass(tmp, object);
>>>>>>>>>>>>> - ld(tmp, in_bytes(Klass::access_flags_offset()), tmp);
>>>>>>>>>>>>> - andi(tmp, tmp, JVM_ACC_IS_BOX_CLASS);
>>>>>>>>>>>>> + lwz(tmp, in_bytes(Klass::access_flags_offset()), tmp);
>>>>>>>>>>>>> + testbitdi(CCR0, R0, tmp,
>>>>>>>>>>>>> exact_log2(JVM_ACC_IS_BOX_CLASS));
>>>>>>>>>>>>> bne(CCR0, slow_case);
>>>>>>>>>>>>> }
>>>>>>>>>>>>>
>>>>>>>>>>>>> diff -r 77852e129401
>>>>>>>>>>>>> src/hotspot/cpu/ppc/macroAssembler_ppc.cpp
>>>>>>>>>>>>> --- a/src/hotspot/cpu/ppc/macroAssembler_ppc.cpp Tue Aug 04
>>>>>>>>>>>> 10:03:57 2020 +0200
>>>>>>>>>>>>> +++ b/src/hotspot/cpu/ppc/macroAssembler_ppc.cpp Tue Aug 04
>>>>>>>>>>>> 16:04:31 2020 +0200
>>>>>>>>>>>>> @@ -2838,8 +2838,8 @@
>>>>>>>>>>>>>
>>>>>>>>>>>>> if (DiagnoseSyncOnPrimitiveWrappers != 0) {
>>>>>>>>>>>>> load_klass(temp, oop);
>>>>>>>>>>>>> - ld(temp, in_bytes(Klass::access_flags_offset()), temp);
>>>>>>>>>>>>> - andi(temp, temp, JVM_ACC_IS_BOX_CLASS);
>>>>>>>>>>>>> + lwz(temp, in_bytes(Klass::access_flags_offset()), temp);
>>>>>>>>>>>>> + testbitdi(CCR0, R0, temp,
>>>>>>>>>>>>> exact_log2(JVM_ACC_IS_BOX_CLASS));
>>>>>>>>>>>>> bne(CCR0, cont);
>>>>>>>>>>>>> }
>>>>>>>>>>>>>
>>>>>>>>>>>>> diff -r 77852e129401
>>>>>>>>>> src/hotspot/cpu/s390/c1_MacroAssembler_s390.cpp
>>>>>>>>>>>>> --- a/src/hotspot/cpu/s390/c1_MacroAssembler_s390.cpp Tue
>>>>>>>>>>>>> Aug 04
>>>>>>>>>>>> 10:03:57 2020 +0200
>>>>>>>>>>>>> +++ b/src/hotspot/cpu/s390/c1_MacroAssembler_s390.cpp Tue
>>>>>>>>>>>>> Aug 04
>>>>>>>>>>>> 16:04:31 2020 +0200
>>>>>>>>>>>>> @@ -91,6 +91,12 @@
>>>>>>>>>>>>> // Save object being locked into the BasicObjectLock...
>>>>>>>>>>>>> z_stg(obj, Address(disp_hdr,
>>>>>>>>>> BasicObjectLock::obj_offset_in_bytes()));
>>>>>>>>>>>>> + if (DiagnoseSyncOnPrimitiveWrappers != 0) {
>>>>>>>>>>>>> + load_klass(Z_R1_scratch, obj);
>>>>>>>>>>>>> + testbit(Address(Z_R1_scratch,
>>>>>>>>>>>>> Klass::access_flags_offset()),
>>>>>>>>>>>> exact_log2(JVM_ACC_IS_BOX_CLASS));
>>>>>>>>>>>>> + z_btrue(slow_case);
>>>>>>>>>>>>> + }
>>>>>>>>>>>>> +
>>>>>>>>>>>>> if (UseBiasedLocking) {
>>>>>>>>>>>>> biased_locking_enter(obj, hdr, Z_R1_scratch,
>>>>>>>>>>>>> Z_R0_scratch, done,
>>>>>>>>>>>> &slow_case);
>>>>>>>>>>>>> }
>>>>>>>>>>>>> diff -r 77852e129401
>>>>>>>>>>>>> src/hotspot/cpu/s390/interp_masm_s390.cpp
>>>>>>>>>>>>> --- a/src/hotspot/cpu/s390/interp_masm_s390.cpp Tue Aug 04
>>>>>>>>>>>>> 10:03:57
>>>>>>>>>>>> 2020 +0200
>>>>>>>>>>>>> +++ b/src/hotspot/cpu/s390/interp_masm_s390.cpp Tue Aug 04
>>>>>>>>>> 16:04:31
>>>>>>>>>>>> 2020 +0200
>>>>>>>>>>>>> @@ -1000,6 +1000,12 @@
>>>>>>>>>>>>> // Load markWord from object into displaced_header.
>>>>>>>>>>>>> z_lg(displaced_header,
>>>>>>>>>>>>> oopDesc::mark_offset_in_bytes(), object);
>>>>>>>>>>>>>
>>>>>>>>>>>>> + if (DiagnoseSyncOnPrimitiveWrappers != 0) {
>>>>>>>>>>>>> + load_klass(Z_R1_scratch, object);
>>>>>>>>>>>>> + testbit(Address(Z_R1_scratch,
>>>>>>>>>>>>> Klass::access_flags_offset()),
>>>>>>>>>>>> exact_log2(JVM_ACC_IS_BOX_CLASS));
>>>>>>>>>>>>> + z_btrue(slow_case);
>>>>>>>>>>>>> + }
>>>>>>>>>>>>> +
>>>>>>>>>>>>> if (UseBiasedLocking) {
>>>>>>>>>>>>> biased_locking_enter(object, displaced_header,
>>>>>>>>>>>>> Z_R1, Z_R0, done,
>>>>>>>>>>>> &slow_case);
>>>>>>>>>>>>> }
>>>>>>>>>>>>> diff -r 77852e129401
>>>>>>>>>>>>> src/hotspot/cpu/s390/macroAssembler_s390.cpp
>>>>>>>>>>>>> --- a/src/hotspot/cpu/s390/macroAssembler_s390.cpp Tue Aug 04
>>>>>>>>>>>> 10:03:57 2020 +0200
>>>>>>>>>>>>> +++ b/src/hotspot/cpu/s390/macroAssembler_s390.cpp Tue Aug 04
>>>>>>>>>>>> 16:04:31 2020 +0200
>>>>>>>>>>>>> @@ -3358,6 +3358,12 @@
>>>>>>>>>>>>> // Load markWord from oop into mark.
>>>>>>>>>>>>> z_lg(displacedHeader, 0, oop);
>>>>>>>>>>>>>
>>>>>>>>>>>>> + if (DiagnoseSyncOnPrimitiveWrappers != 0) {
>>>>>>>>>>>>> + load_klass(Z_R1_scratch, oop);
>>>>>>>>>>>>> + testbit(Address(Z_R1_scratch,
>>>>>>>>>>>>> Klass::access_flags_offset()),
>>>>>>>>>>>> exact_log2(JVM_ACC_IS_BOX_CLASS));
>>>>>>>>>>>>> + z_btrue(done);
>>>>>>>>>>>>> + }
>>>>>>>>>>>>> +
>>>>>>>>>>>>> if (try_bias) {
>>>>>>>>>>>>> biased_locking_enter(oop, displacedHeader, temp,
>>>>>>>>>>>>> Z_R0, done);
>>>>>>>>>>>>> }
>>>>>>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
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