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From "Geir Magnusson Jr." <g...@pobox.com>
Subject Re: [drlvm] finalizer design questions
Date Sun, 31 Dec 2006 17:52:29 GMT

On Dec 31, 2006, at 10:18 AM, Weldon Washburn wrote:

> On 12/29/06, Pavel Afremov <pavel.n.afremov@gmail.com> wrote:
>>
>> I've checked Weldon's finalization scheme and two existing schemes on
>> Weldon's test in mode 1 and 2.
>> On my Machine WinXP HT Pentium 4 I've got following results.
>>
>> Weldon's design (on my machine 2 threads with highest priority).
>>            Mode 1: 1/50 (main loop/finalizer call)
>>            Mode 2: 1/50 (main loop/finalizer call)
>
>
> This looks good to me.  Its close enough for the current state of  
> drlvm.  In
> other words, don't try to precisely replicate the performance  
> numbers I
> collected from Sun 1.5.0.
>
> Multithreading java scheme (old DRLVM scheme)
>>            Mode 1: 1/1 (main loop/finalizer call)
>>            Mode 2  1/250 (main loop/finalizer call)
>> One native thread with highest priority (like new GC v5 scheme)
>>            Mode 1: 1/1 (main loop/finalizer call)
>>            Mode 2: 1/1 (main loop/finalizer call)
>
>
> Its unclear if you actually ran GCv5 finalizer code or something  
> "like new
> GC v5 scheme".  I don't know what the data means.
>
> From Weldon's data SUN 1.5.0 JVM has:
>>            Mode 1: 1/50 (main loop/finalizer call) (may be 1/90)
>>            Mode 2: 1/173 (main loop/finalizer call) (15 / 2600  =  
>> 1/173)
>>
>> As I understand the ideal finalization scheme should provide:
>>            Mode 1: 1/1 (main loop/finalizer call)
>>            Mode 2: 0/1 (main loop/finalizer call)
>
>
> The point is that the "ideal finalization" design needs to be  
> driven by what
> important commercial workloads require.

I'd be stunned if there were any important commercial workloads that  
used finalizers.  (Nothing from SPEC is a commercial workload...)

> It will be a while before these
> workloads run fast and stable on drlvm.  In other words, drlvm is  
> not yet
> ready for investigating the final finalization scheme.

I don't agree with that conclusion, as I don't think that they are  
connected concepts.

> Incidentally, the
> data collected on Sun 1.5.0 contradicts the "ideal finalization  
> scheme"
> suggested above.  Given a choice, I would rather do something  
> similar to a
> commercial JVM implementation at this point in time.

Me too

geir

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