[9] RFR(M): 8078554: Compiler: implement ranges (optionally constraints) for those flags that have them missing
Christian Thalinger
christian.thalinger at oracle.com
Mon Oct 12 17:58:22 UTC 2015
> On Oct 11, 2015, at 10:06 PM, Zoltán Majó <zoltan.majo at oracle.com> wrote:
>
> Hi,
>
>
> On 10/09/2015 11:33 PM, Christian Thalinger wrote:
>> After JEP 243 was integrated we fail one of the new tests with:
>>
>> intx TypeProfileWidth=8 is outside the allowed range [ 0 ... 4 ]
>>
>> The reason is that JVMCI can support more than 4 type profiles. Currently the default is 8:
>>
>> if (UseJVMCICompiler) {
>> if (FLAG_IS_DEFAULT(TypeProfileWidth)) {
>> TypeProfileWidth = 8;
>> }
>> }
>>
>> We should increase the range. Not sure what a good number would be, though. Maybe 100 just to be safe?
>
> 16 is already too large -- it triggers an assert on a platform we support. I'll look into extending the range to 8.
I didn’t try :-) Thanks.
>
> Best regards,
>
>
> Zoltan
>
>>
>>> On Oct 8, 2015, at 5:52 AM, Zoltán Majó <zoltan.majo at oracle.com <mailto:zoltan.majo at oracle.com><mailto:zoltan.majo at oracle.com <mailto:zoltan.majo at oracle.com>>> wrote:
>>>
>>> Thank you, Tobias, for the review!
>>>
>>> Best regards,
>>>
>>>
>>> Zoltán
>>>
>>> On 10/08/2015 04:10 PM, Tobias Hartmann wrote:
>>>> Hi Zoltán,
>>>>
>>>> On 08.10.2015 14:07, Zoltán Majó wrote:
>>>>> Hi Tobias,
>>>>>
>>>>>
>>>>> thank you for the feedback!
>>>>>
>>>>> On 10/07/2015 03:38 PM, Tobias Hartmann wrote:
>>>>>> Hi Zoltan,
>>>>>>
>>>>>> I had a look at your changes and just spotted some minor things:
>>>>>>
>>>>>> globals_sparc.hpp:
>>>>>> - I think there is a '\' missing in line 119
>>>>> thank you for spotting that!
>>>>>
>>>>>> globals_x86.hpp:
>>>>>> - Isn't this also a compiler flag we should add range checks for?
>>>>>> 136 product(uintx, RTMRetryCount, 5,
>>>>> JEP 245 considers it as a runtime flag and JDK-8078556 "Runtime: implement ranges..." [1] will take care of it. But you are right, that flag could be also considered a compiler flag.
>>>> Okay, thanks for pointing that out.
>>>>
>>>>>> commandLineFlagConstraintsCompiler.cpp:
>>>>>> - I think there is a "rule" that the include statements should be in alphabetical order
>>>>> Yes, I think there is such a rule (or convention). I diverged from the rule because the include of code/relocInfo.hpp depends on 'os', 'vm_page_size', and 'Metadata'. Therefore, "oops/metadata.hpp" and "runtime/os.hpp" must be included before relocInfo.hpp (otherwise the Solaris compiler complains). The remaining includes are ordered alphabetically.
>>>> Okay, makes sense.
>>>>
>>>>>> - the indentation is wrong here:
>>>>>> 179 return Flag::VIOLATES_CONSTRAINT;
>>>>> I updated the indentation.
>>>>>
>>>>> Here is the updated webrev:
>>>>> http://cr.openjdk.java.net/~zmajo/8078554/webrev.02/ <http://cr.openjdk.java.net/~zmajo/8078554/webrev.02/><http://cr.openjdk.java.net/%7Ezmajo/8078554/webrev.02/ <http://cr.openjdk.java.net/%7Ezmajo/8078554/webrev.02/>>
>>>>>
>>>>> I re-tested the updated webrev with JPRT (testset hotspot), all tests pass.
>>>> Looks good to me (not a Reviewer).
>>>>
>>>> Best,
>>>> Tobias
>>>>
>>>>
>>>>> Thank you and best regards,
>>>>>
>>>>>
>>>>> Zoltan
>>>>>
>>>>> [1] https://bugs.openjdk.java.net/browse/JDK-8078556 <https://bugs.openjdk.java.net/browse/JDK-8078556>
>>>>>> Best,
>>>>>> Tobias
>>>>>
>>>>>> On 06.10.2015 13:45, Zoltán Majó wrote:
>>>>>>> Hi Roland,
>>>>>>>
>>>>>>>
>>>>>>> thank you for the feedback!
>>>>>>>
>>>>>>> On 10/02/2015 03:55 PM, Roland Westrelin wrote:
>>>>>>>> Hi Zoltan,
>>>>>>>>
>>>>>>>>> Webrev:http://cr.openjdk.java.net/~zmajo/8078554/ <http://cr.openjdk.java.net/~zmajo/8078554/><http://cr.openjdk.java.net/%7Ezmajo/8078554/ <http://cr.openjdk.java.net/%7Ezmajo/8078554/>>
>>>>>>>> c2_globals.hpp
>>>>>>>>
>>>>>>>> That one is not correct:
>>>>>>>> 461 product(intx, MaxNodeLimit, 80000, \
>>>>>>>> 462 "Maximum number of nodes") \
>>>>>>>> 463 range(1000, 80000) \
>>>>>>>>
>>>>>>>> I think the upper bound should be max_juint
>>>>>>> You are right that the limit of 80'000 is too conservative. But max_j*u*int as an upper bound would cause an overflow when parsing the flag's value, because on 32-bit machines intx is a 32-bit signed integer.
>>>>>>>
>>>>>>> Using max_jint instead of max_j*u*int as an upper bound would not cause an overflow at parse time. However, in Parse::do_call() the maximum node limit is increased by 3 times for jsr292 users
>>>>>>>
>>>>>>> C->set_max_node_limit(3*MaxNodeLimit);
>>>>>>>
>>>>>>> If MaxNodeLimit == max_jint, this expression will overflow, I think.
>>>>>>>
>>>>>>> So I set the limit to (max_jint / 3) in the updated webrev.
>>>>>>>
>>>>>>> If we would set MaxNodeLimit to max_j*u*int / 3 (instead of max_jint / 3), the expression 3 * MaxNodeLimit would overflow as well. Changing the type of the flag from intx to uintx could let use use max_j*u*int / 3 as an upper bound, but that is most likely not worth the effort.
>>>>>>>
>>>>>>>> 699 product(intx, LiveNodeCountInliningCutoff, 40000, \
>>>>>>>> 700 "max number of live nodes in a method") \
>>>>>>>> 701 range(0, max_juint / 8) \
>>>>>>>>
>>>>>>>> Out of curiosity why max_juint / 8 (not that it makes much of a difference)?
>>>>>>> In Compile::inline_incrementally, the 80% of LiveNodeCountInliningCutoff is computed the following way:
>>>>>>>
>>>>>>> if (low_live_nodes < (uint)LiveNodeCountInliningCutoff * 8 / 10) {
>>>>>>>
>>>>>>> If LiveNodeCountInliningCutoff == max_juint, we'd have an overflow because of the multiplication by 8.
>>>>>>>
>>>>>>>> arguments.cpp
>>>>>>>>
>>>>>>>> 1099 Tier3InvokeNotifyFreqLog = 0;
>>>>>>>> 1100 Tier4InvocationThreshold = 0;
>>>>>>>>
>>>>>>>> Why that change?
>>>>>>> I proposed that change because I misread the code. I reverted that change and also changed the range of all Tier*FreqLog flags from range(1, 30) to range(0, 30).
>>>>>>>
>>>>>>>> globals.hp
>>>>>>>>
>>>>>>>> 2870 product_pd(uintx, TypeProfileLevel, \
>>>>>>>> 2871 "=XYZ, with Z: Type profiling of arguments at call; " \
>>>>>>>> 2872 "Y: Type profiling of return value at call; " \
>>>>>>>> 2873 "X: Type profiling of parameters to methods; " \
>>>>>>>> 2874 "X, Y and Z in 0=off ; 1=jsr292 only; 2=all methods") \
>>>>>>>> 2875 range(0, 222)
>>>>>>>>
>>>>>>>> Legal values are 0, 1, 2, 10, 11, 12, 100, 101, 102, 110, 111, 112 etc.
>>>>>>>>
>>>>>>>> 70 is not for instance. So range(0, 222) is incorrect.
>>>>>>> I agree. I removed the range check and implemented a constraint function instead (TypeProfileLevelConstraintFunc).
>>>>>>>
>>>>>>>> 2877 product(intx, TypeProfileArgsLimit, 2, \
>>>>>>>> 2878 "max number of call arguments to consider for type profiling") \
>>>>>>>> 2879 range(0, 16) \
>>>>>>>>
>>>>>>>> 2880 \
>>>>>>>> 2881 product(intx, TypeProfileParmsLimit, 2, \
>>>>>>>> 2882 "max number of incoming parameters to consider for type profiling"\
>>>>>>>> 2883 ", -1 for all") \
>>>>>>>> 2884 range(-1, 64)
>>>>>>>>
>>>>>>>> Why 16 and 64?
>>>>>>> These are the largest values that work on all platforms we support.
>>>>>>>
>>>>>>> Here is the updated webrev: http://cr.openjdk.java.net/~zmajo/8078554/webrev.01/ <http://cr.openjdk.java.net/~zmajo/8078554/webrev.01/><http://cr.openjdk.java.net/%7Ezmajo/8078554/webrev.01/ <http://cr.openjdk.java.net/%7Ezmajo/8078554/webrev.01/>>
>>>>>>>
>>>>>>> I repeated the testing with JPRT. I also executed the currently disabled TestOptionsWithRanges.java test on all platforms we support. All tests pass.
>>>>>>>
>>>>>>> Thank you and best regards,
>>>>>>>
>>>>>>>
>>>>>>> Zoltan
>>>>>>>
>>>>>>>> Roland.
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