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From Egor Pasko <egor.pa...@gmail.com>
Subject Re: [jira] Commented: (HARMONY-5399) [drlvm][jit] Enabling arraycopy optimization for primitive types when write barriers are enabled
Date Fri, 18 Jan 2008 09:52:28 GMT
On the 0x3CF day of Apache Harmony Xiao-Feng Li wrote:
> On Jan 18, 2008 2:30 PM, George Timoshenko (JIRA) <jira@apache.org> wrote:
> >
> >     [ https://issues.apache.org/jira/browse/HARMONY-5399?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12560243#action_12560243
]
> >
> > George Timoshenko commented on HARMONY-5399:
> > --------------------------------------------
> >
> > I have one consern.
> >
> > By the modification of "arraycopyOptimizable" you turn of the both
> >
> > genArrayCopy and
> > genArrayCopyRepMove
> >
> > optimizations of the arrays of Object types.
> >
> > BUT the first one, genArrayCopy, does not use REP instruction. It generates a copying
loop so it can work with WB.
> 
> 
> For array write, it's ok to have only one WB for the whole object. In
> my current generational GC design, I use WB actually for object
> remembering rather than slot remembering. So one WB for the whole
> arraycopy is enough.
> 
> (Well, write barrier support in DRLVM needs cleanup thenafter.)

So, you are not planning to get WB for each object in the array in the
nearest future? then we can stick to one WB per array for now before
the cleanup happens, right?

I would +1 then.

P.S. hm, I thought you have several GC designs and experiment between
them.. and some had WB per slot strategy..

> Thanks,
> xiaofeng
> 
> >
> > > [drlvm][jit] Enabling arraycopy optimization for primitive types when write
barriers are enabled
> > > ------------------------------------------------------------------------------------------------
> > >
> > >                 Key: HARMONY-5399
> > >                 URL: https://issues.apache.org/jira/browse/HARMONY-5399
> > >             Project: Harmony
> > >          Issue Type: Improvement
> > >         Environment: All
> > >            Reporter: Aleksey Shipilev
> > >         Attachments: WB-2.patch, WB-3.patch, WB-4.patch
> > >
> > >
> > > JIT arraycopy optimization is disabled automatically when WB are enabled. Attached
patch re-enables arraycopy optimization for arrays of primitive types, which shouldn't interfere
with WB activity.
> >
> > --
> > This message is automatically generated by JIRA.
> > -
> > You can reply to this email to add a comment to the issue online.
> >
> >
> 
> 
> 
> -- 
> http://xiao-feng.blogspot.com
> 

-- 
Egor Pasko


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