Pls review 6887571

[Jon Masamitsu]

Comment should probably say "initial heap size" instead of "minimum
heap size".

1357     if (!FLAG_IS_DEFAULT(InitialHeapSize)) {
1358       // A minimum heap size was specified on the command line,


Instead of this,

2719   // Set heap size based on available physical memory.
2720   // CMS uses its own heap size ergo.
2721   if (!UseConcMarkSweepGC) {
2722     set_heap_size();
2723   }
2724
2725   if (UseParallelGC || UseParallelOldGC) {
2726     // Set some flags for ParallelGC if needed.
2727     set_parallel_gc_flags();
2728   } else if (UseConcMarkSweepGC) {
2729     // Set some flags for CMS
2730     set_cms_and_parnew_gc_flags();
2731   } else if (UseParNewGC) {
2732     // Set some flags for ParNew
2733     set_parnew_gc_flags();
2734   } else if (UseG1GC) {
2735     // Set some flags for garbage-first, if needed.
2736     set_g1_gc_flags();
2737   }

consider

if (UseConcMarkSweepGC) {
   // Set some flags for cms and ParNew.  If both
   // UseConcMarkSweepGC and UseParNewGC are set,
   // this is the call that should be done.
   set_cms_and_parnew_gc_flags();
} else {
   set_heap_size();
   if (UseParallelGC || UseParallelOldGC) {
     // Set some flags for ParallelGC if needed.
     set_parallel_gc_flags();
   } else if (UseParNewGC) {
     // Set some flags for ParNew
     set_parnew_gc_flags();
   } else if (UseG1GC) {
     // Set some flags for garbage-first, if needed.
     set_g1_gc_flags();
   }
}


I'd suggest adding the newly obsoleted flags (e.g., DefaultMaxRAM)
to the obsolete_jvm_flags[] in arguments.cpp.  For example

   { "DefaultMaxRAM)", JDK_Version::jdk_update(6,16), JDK_Version::jdk(8) }


That's all.


On 10/27/09 16:01, Paul Hohensee wrote:
> .02 has the fix for line 1105.
> 
> I'll change MaxErgoHeapSize to ErgoHeapSizeLimit, unless someone
> else has another opinion.  I'm not proud. :)
> 
> Thanks for the review, and for reviewing interim versions.
> 
> Paul
> 
> Jon Masamitsu wrote:
>> Paul,
>>
>> Just a couple of comments from the .01 version
>> of the webrev.  I haven't started the .02 version
>> yet so may have more comments after I do.
>>
>> Jon
>>
>> arguments.cpp
>>
>> 1105       InitialHeapSize = min_new + OldSize;
>>
>> Use FLAG_SET_ERGO()
>>
>> FLAG_SET_ERGO(uintx, InitialHeapSize, min_new + OldSize);
>>
>> Sometimes in the setting of the GC policies we like to
>> know how the flag was set.
>>
>> I like ErgoHeapSizeLimit instead of
>> MaxErgoHeapSize but just my preference.
>>
>>
>>
>> On 10/27/09 09:26, Paul Hohensee wrote:
>>> 6887571: Increase default heap config sizes
>>>
>>> Webrev here
>>>
>>> http://cr.openjdk.java.net/~phh/6887571/webrev.01/
>>>
>>> Some background:
>>>
>>> The default client vm heap config since 2000 for sparc32 has been the 
>>> equivalent of
>>>
>>> -Xmx64m -XX:OldSize=4m -XX:NewSize=2m -XX:NewRatio=8
>>> -XX:SurvivorRatio=8 -XX:MaxTenuringThreshold=15
>>>
>>> and for 32-bit x86
>>>
>>> -Xmx64m -XX:OldSize=4m -XX:NewSize=1m -XX:NewRatio=12
>>> -XX:SurvivorRatio=8 -XX:MaxTenuringThreshold=15
>>>
>>> OldSize and NewSize are the initial committed sizes of the old and 
>>> young generations
>>> respectively.  A minor gc is required to increase the committed size 
>>> of the young gen,
>>> while a full gc is required to increase the committed size of the old 
>>> gen.
>>>
>>> At the time, 64m was half of the 128m of memory typically available 
>>> on high-end
>>> desktops, many client applications were satisfied with small heaps 
>>> (hence the
>>> low -Xms value), and gc times were such that the young gen had to be 
>>> small
>>> in order to minimize pause times.
>>>
>>> Since that time, low end desktops and laptops, as well as netbooks 
>>> and smartbooks,
>>> typically come with 256m, client applications have become much more 
>>> "server-like",
>>> and we've realized that a small young gen size increases the 
>>> frequency of young gcs
>>> and the amount of transient data promoted to the old gen to levels 
>>> that noticeably
>>> impact startup and steady-state performance, principally by provoking 
>>> full gcs.
>>>
>>> This change extends server class heap sizing to the client with a few 
>>> changes.
>>> Server heap sizing ergonomics should be unaffected.
>>>
>>> 1. NewRatio is set to 2 for all platforms to accomodate an increase 
>>> in transient data size.
>>>
>>> 2. SurvivorRatio is set to 8 for all platforms.  It was 8 for every 
>>> platform except
>>> 64-bit x86 (where it was 6) in any case, so it isn't a big change.
>>>
>>> 3. MaxTenuringThreshold is left at 15 (the maximum).
>>>
>>> 4. I added MaxRAM, whose implemented definition matches the current 
>>> comment for DefaultMaxRAM
>>> in globals.hpp.  MaxRAM is the maximum physical memory size used to 
>>> compute MaxHeapSize
>>> rather than the maximum possible value of MaxHeapSize set by 
>>> ergonomics.  I replaced
>>> DefaultMaxRAM with MaxErgoHeapSize for the latter purpose.  I added 
>>> support for a new
>>> argument type, uint64_t, and used it as the type of MaxRAM.  uintx 
>>> doesn't have the necessary
>>> range on 32-bit systems: a user might want to specify 4g for MaxRAM 
>>> on a 32-bit system.
>>>
>>> 5. The other Default* switches have been stripped of the "Default" 
>>> prefix, since to me their
>>> values are just as much "default" values as the values of any of 
>>> other vm switch, and those don't
>>> have a "Default" prefix.  I left DefaultMaxRAMFraction as a synonym 
>>> for MaxRAMFraction for
>>> the moment because QA uses it.  When they change to MaxRAMFraction, I 
>>> intend to remove
>>> DefaultMaxRAMFraction.
>>>
>>> 6. In arguments.cpp, set_heap_size() replaces set_server_heap_size() 
>>> and is used for everything
>>> except CMS.  CMS has it's own, incompatible (I know: I tried it), 
>>> heap sizing ergonomics.
>>>
>>> 7. The minimum committed size of the old gen (OldSize) remains at 4m 
>>> and the minimum
>>> committed size of the young gen (NewSize) increases to 4m.  Note that 
>>> these are the minimum,
>>> not initial sizes.  NewSize is made common to all platforms.
>>>
>>> 8. I added a switch InitialHeapSize that can be used to set the 
>>> initial committed size of the heap.
>>> Absent specification by InitialHeapSize, the initial committed size 
>>> is 1/64th of physical memory
>>> or OldSize + NewSize, whichever is larger.
>>>
>>> 9. I cleaned up some formatting, esp. in globals.hpp.
>>>
>>> 10. The default MaxHeapSize is raised from 64m to 96m.  For systems 
>>> with <= MaxHeapSize
>>> physical memory, the minimum heap size is 1/MinRAMFraction of 
>>> physical memory.  The
>>> default value of MinRAMFraction is 2.  Thus, a 256m box gets a 96m 
>>> heap, as does a 128m
>>> box, but a 96m box gets a 48m heap and a 64m box gets a 32m heap.  
>>> The default values of
>>> MaxRAM and MaxRAMFraction bound the maximum heap size to 256m for the 
>>> client vms,
>>> 1g for 32-bit server vms and 32g for 64-bit server vms.  The values 
>>> for the server vms are
>>> the same as before.  I picked 256m for client because I wanted to 
>>> bound resource utilization
>>> on client systems.  Also, benchmarks runs showed no extra benefit 
>>> from going to 512m heaps.
>>> 512m is the safe maximum for the serial collector.
>>>
>>> Thanks,
>>>
>>> Paul
>>>
>>>
>>>
>>>
>>>