<br><br>On Thursday, April 28, 2016, Sujit K M <<a href="mailto:kmsujit@gmail.com">kmsujit@gmail.com</a>> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On Thu, Apr 28, 2016 at 5:30 PM, Edward Capriolo <<a href="javascript:;" onclick="_e(event, 'cvml', 'edlinuxguru@gmail.com')">edlinuxguru@gmail.com</a>> wrote:<br>
> The java class file format is well documented. Basically one pointer to the<br>
> runtime class of the object followed by the object.<br>
<br>
So you mean to say Class file size on the filesystem is the Object Size.<br>
<br>
><br>
> If a given language is reference counted each object has one extra atomic<br>
> field to count references.<br>
<br>
So you mean to say garbage collection.<br>
<br>
><br>
> If a given language does not have objects but instead uses maps (that repeat<br>
> the fields evey instance) that is going to be a more large object in memory.<br>
<br>
Big data I guess.<br>
<br>
><br>
> While i am not a large expert in this i believe javas approach is like a c<br>
> struct with the exception the first word size bytes are a pointer to the<br>
> type of class so that instances can be runtime inspected.<br>
><br>
> Java also has a very clever system for compressing 64 bit pointers.. see<br>
> compressedOOPs option. I have not heard much of this optimization anywhere<br>
> else.<br>
<br>
Zlib I guess.<br>
<br>
><br>
> On Thursday, April 28, 2016, Sujit K M <<a href="javascript:;" onclick="_e(event, 'cvml', 'kmsujit@gmail.com')">kmsujit@gmail.com</a>> wrote:<br>
>><br>
>> > Anecdotal. Keep in mind I have tested this and you can create 'a lot<br>
>> > more<br>
>> > objects' given the same RAM than many other popular non java languages.<br>
>> > :)<br>
>><br>
>> Could you please clarify further? I mean does it involve a object size<br>
>> on the JVM.<br>
>> How to measure the size occupied by the Object? How much extra space the<br>
>> JVM<br>
>> needs? What is JDK Feature that Let's you claim this?<br>
>><br>
>> I have serious questions regarding this claim. As Interpreted or JIT<br>
>> compiled languages<br>
>> should in reality occupy more space.<br>
>><br>
>> ><br>
>> > On Wed, Apr 27, 2016 at 4:13 PM, Pete Wright <<a href="javascript:;" onclick="_e(event, 'cvml', 'pete@nomadlogic.org')">pete@nomadlogic.org</a>><br>
>> > wrote:<br>
>> >><br>
>> >><br>
>> >><br>
>> >> On 04/26/2016 03:56 AM, Brian Coca wrote:<br>
>> >>><br>
>> >>> As many a Java dev has told me: "the only problem is that you did not<br>
>> >>> install enough RAM, just add it, it's cheap!"<br>
>> >>><br>
>> >>><br>
>> >><br>
>> >> and therein is the issue - in practice i've found that by adding more<br>
>> >> memory to a JVM heap will tend to worsen GC pauses, especially for<br>
>> >> latency<br>
>> >> sensitive operations. then you get to do all sorts of fun stuff like<br>
>> >> storing cached objects outside of the JVM or lord knows what.<br>
>> >><br>
>> >> i spent about 3 months trying to help a team tune their java app when<br>
>> >> they<br>
>> >> noticed it would periodically show latencies of several seconds. they<br>
>> >> kept<br>
>> >> adding more memory to the heap, which made things worse. once we<br>
>> >> turned on<br>
>> >> debugging metrics for GC it became painfully apparent that due to the<br>
>> >> huge<br>
>> >> heap that they had allocated GC was taking ages to complete and<br>
>> >> stopping to<br>
>> >> world in the process. good times :)<br>
>> >><br>
>> >> -pete<br>
>> >><br>
>> >> --<br>
>> >> Pete Wright<br>
>> >> <a href="javascript:;" onclick="_e(event, 'cvml', 'pete@nomadlogic.org')">pete@nomadlogic.org</a><br>
>> >><br>
>> >> _______________________________________________<br>
>> >> talk mailing list<br>
>> >> <a href="javascript:;" onclick="_e(event, 'cvml', 'talk@lists.nycbug.org')">talk@lists.nycbug.org</a><br>
>> >> <a href="http://lists.nycbug.org/mailman/listinfo/talk" target="_blank">http://lists.nycbug.org/mailman/listinfo/talk</a><br>
>> ><br>
>> ><br>
>> ><br>
>> > _______________________________________________<br>
>> > talk mailing list<br>
>> > <a href="javascript:;" onclick="_e(event, 'cvml', 'talk@lists.nycbug.org')">talk@lists.nycbug.org</a><br>
>> > <a href="http://lists.nycbug.org/mailman/listinfo/talk" target="_blank">http://lists.nycbug.org/mailman/listinfo/talk</a><br>
>><br>
>> _______________________________________________<br>
>> talk mailing list<br>
>> <a href="javascript:;" onclick="_e(event, 'cvml', 'talk@lists.nycbug.org')">talk@lists.nycbug.org</a><br>
>> <a href="http://lists.nycbug.org/mailman/listinfo/talk" target="_blank">http://lists.nycbug.org/mailman/listinfo/talk</a><br>
><br>
><br>
><br>
> --<br>
> Sorry this was sent from mobile. Will do less grammar and spell check than<br>
> usual.<br>
<br>
_______________________________________________<br>
talk mailing list<br>
<a href="javascript:;" onclick="_e(event, 'cvml', 'talk@lists.nycbug.org')">talk@lists.nycbug.org</a><br>
<a href="http://lists.nycbug.org/mailman/listinfo/talk" target="_blank">http://lists.nycbug.org/mailman/listinfo/talk</a><br>
</blockquote><div><br></div><div>No i am not talking using zlib on large byte arrays. What compressedOOps does is use something like a varint pointer between objects so that not every object pointer is 64 bits on a 64 bit platform.</div><br><br>-- <br>Sorry this was sent from mobile. Will do less grammar and spell check than usual.<br>