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From Naveen Neelakantam <neela...@uiuc.edu>
Subject Re: [drlvm][jit] abcd and devirtualizer patches was: [OT] Harmony used in accepted research paper
Date Fri, 20 Apr 2007 07:36:33 GMT

On Apr 20, 2007, at 1:42 AM, Egor Pasko wrote:

> On the 0x2B6 day of Apache Harmony Naveen Neelakantam wrote:
>> I've uploaded a patch against Egor's ABCD implementation in
>> HARMONY-1788.   It passes the tests included with HARMONY-2141,
>> HARMONY-2144 and HARMONY-2147, and removes all but one bounds check
>> from BidirectionalBubbleSort in HARMONY-1564.  I've also ran the
>> DaCapo benchmarks using it and it doesn't seem to break anything.
> Naveen, I am somewhere in the middle of looking at your great
> work. Sorry for being so slow, but, you know, making sure that ABCD
> works as expected is not an easy thing to do :)

Indeed.  :-)

> One major question for now: Why do we need two separate inequality
> graphs, for upper and lower bound problems? You name the lower bound
> graph as 'inverted', but I do not see any 'inverted' edges in tests I
> tried. It seems like we can merge two graphs into one in the way extra
> pi edges they won't disturb each other.
> Do you have any quick counter-example to this approach (so I do not
> stagger for a long time searching it)?

I could be wrong, but I think you need two different inequality  
graphs.  If I recall correctly, the reason has to do with the types  
of constraints inserted for conditional branch operations are  
different in the upper and lower bound problems.

I'll try to work up an example why tomorrow.

But maybe you are suggesting that we could have a single data- 
structure that logically represents both the upper and lower bound  
problems.  If so, I think that might be possible (and would certainly  
be more efficient).


> Will ask/comment more soon.
>> I've also opened a JIRA issue for my profile-based abstract and
>> virtual call devirtualization patch: HARMONY-3630.
>> Naveen
>> On Apr 9, 2007, at 12:23 AM, Pavel Ozhdikhin wrote:
>>> Naveen,
>>> Congrartulations! I eager to read your paper - please announce a
>>> link here
>>> when it's available.
>>> I'm also looking forward to a new ABCD impementation from Egor and
>>> your -
>>> your both did a lot to make it working, now it's time to make use
>>> of it in
>>> Harmony.
>>> Thanks,
>>> Pavel
>>> On 4/8/07, Naveen Neelakantam <neelakan@uiuc.edu> wrote:
>>>> Hello all,
>>>> You might like to hear that a paper which used Apache Harmony as  
>>>> part
>>>> of a research infrastructure was accepted to ISCA 2007  
>>>> (International
>>>> Symposium on Computer Architecture).  I will be presenting this  
>>>> work
>>>> in San Diego in June and will be sure to include a slide plugging
>>>> Harmony.
>>>> I would like to thank all of the JVM and classlib developers who  
>>>> made
>>>> such an endeavor even possible.  You are doing a wonderful job, and
>>>> it is much appreciated!  Please pat yourself on the back.  :-)
>>>> BTW, in the process of doing this work I helped get Egor Pasko's  
>>>> ABCD
>>>> reimplementation finished, and I added profile-based abstract call
>>>> and virtual devirtualization to the code from HARMONY-2012.  I'll
>>>> post the patches after the weekend.
>>>> Thanks again,
>>>> Naveen
> -- 
> Egor Pasko

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