RFR (M) 8139551: Scalability problem with redefinition - multiple code cache walks

[David Holmes]

On 5/02/2019 8:30 am, serguei.spitsyn at oracle.com wrote:
> Hi Coleen,
> 
> Looks good in general.
> 
> Just a couple minor comments below.
> 
> I hope, you will update the copyright years before the push.
> 
> 
> http://cr.openjdk.java.net/~coleenp/2019/8139551.01/webrev/test/hotspot/jtreg/runtime/RedefineTests/TestMultipleClasses.java.html
> 
>    Nice test!
> 
>    37 import java.lang.reflect.*;
>    38 import jdk.test.lib.compiler.InMemoryJavaCompiler;
>    39 import java.lang.instrument.*;
> 
>    The imports above can be re-ordered.
> 
>    44         return new String("public class B" + count + " {" +
>    45                 "   public static void compiledMethod() { " +
>    46                 "       try{" +
>    47                 "          Thread.currentThread().sleep(1); " +
>    48                 "       } catch(InterruptedException ie) {" +
>    49                 "       }" +
>    50                 "   }" +
>    51                 "}");
> 
>    Not clear, why sleep is needed here.

Presumably just to give it some code and consume some time.

Nit: But it should just be:

Thread.sleep(1)

not

Thread.currentThread().sleep(1);

sleep is a static method and as with all Thread static methods always 
applies to the current thread.

David

> 
> Thanks,
> Serguei
> 
> 
> On 2/4/19 12:34, serguei.spitsyn at oracle.com wrote:
>> Added the serviceability-dev back.
>>
>> Thanks,
>> Serguei
>>
>>
>> On 2/4/19 07:18, coleen.phillimore at oracle.com wrote:
>>>
>>> open webrev at 
>>> http://cr.openjdk.java.net/~coleenp/2019/8139551.01/webrev
>>> bug link https://bugs.openjdk.java.net/browse/JDK-8139551
>>>
>>> The links.
>>> Thanks,
>>> Coleen
>>>
>>> On 2/4/19 10:08 AM, coleen.phillimore at oracle.com wrote:
>>>> Summary: Walk code cache and deoptimize once per redefinition.*
>>>>
>>>> *This change touches the AOT and code cache code.  I tried to 
>>>> describe it in the comments in the RFE.  Basically, for 
>>>> redefinition, we walk the code cache per class redefined in order to 
>>>> find evol_method dependencies, then deoptimize if we find them, and 
>>>> then walk the code cache again to mark the deoptimized nmethods as 
>>>> not_entrant.
>>>>
>>>> I replaced this with only marking any nmethods for the class's 
>>>> methods to deoptimize (following InstanceKlass::_methods), also 
>>>> marking aot methods dependent on the class, and then doing the code 
>>>> cache walk to follow the evol_method dependencies at the end of 
>>>> redefinition for all the classes. The new code uses the 
>>>> Method::is_old() flag rather than comparing each method in the 
>>>> InstanceKlass.  Then deoptimization and marking not_entrant is done 
>>>> once at the end of the redefinition as well.
>>>>
>>>> Tested with tier1-6, all the redefinition tests locally:
>>>>
>>>> make test TEST=open/test/hotspot/jtreg/vmTestbase/nsk/jvmti >&jvmti.out
>>>> make test TEST=open/test/hotspot/jtreg/vmTestbase/nsk/jdi >&jdi.out
>>>> make test TEST=open/test/hotspot/jtreg/runtime/RedefineTests 
>>>> >&redefine.out
>>>> make test TEST=open/test/jdk/java/lang/instrument >&instrument.out
>>>>
>>>> new test, and JMH test (see CR for results).
>>>>
>>>> Thanks,
>>>> Coleen
>>>>
>>>>
>>>
>>
>