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Posted to dev@harmony.apache.org by Craig Zilles <zi...@cs.uiuc.edu> on 2006/09/19 22:24:41 UTC
question about support for compressed StringBuffers
I noticed in the file trunk/vm/vmcore/src/util/vm_strings.cpp there
is some code to support the storage of strings in arrays of (8b)
bytes rather than arrays of (16b) unsigned shorts. In the debugger,
I placed breakpoints in this code, and it was never active in my run.
Can someone tell me the current status of this code and, if it is
active, how I can turn it on? (From inspecting the source, it looked
inactive via hardcoding "false" on whether to compress the strings).
I might be interested in working on this code.
- Craig
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Re: question about support for compressed StringBuffers
Posted by Weldon Washburn <we...@gmail.com>.
On 9/22/06, Craig Zilles <zi...@cs.uiuc.edu> wrote:
>
>
> Okay, I'm going to be playing around with this code and other
> approaches for "[C" compression.
>
> Weldon -
>
> you say:
>
> > historically things like string compression make a difference to
> > heap footprint and cache miss performance
>
> do you know of other VMs that do this optimizations and if so if
> there is any public documentation?
Actually, I intentionally do not know about other VM implementations. Its a
clean room thing. In the past, I worked on ORP which morphed into DRLVM. I
do remember some experiments on compressing [C. From what I recall, it had
benefit. The unused code you see in the source base is probably from these
experiments.
> - Craig
>
>
> On Sep 22, 2006, at 7:32 AM, Weldon Washburn wrote:
> > hmm... I tried to putting a standard title on this email. It
> > looks like we
> > all suffer from too much email. So I repeat what I said earlier.
> >
> > All,
> > I took a look at this code. I vote for keeping it. The reason is
> > because
> > Java is string intensive and historically things like string
> > compression
> > make a difference to heap footprint and cache miss performance.
> > It looks
> > like a significant amount of work has already been put in this code.
> >
> > Craig,
> > It would be great if you can work on this code and get it going. I
> > would be
> > happy to work with you to get the mods committed to Harmony svn.
> >
> >
> >
> >
> >
> > On 9/22/06, Alexey Varlamov <al...@gmail.com> wrote:
> >>
> >> Just a thought:
> >> DRLVM yet does not support 4-byte supplement characters of UTF8
> >> (6-bytes encoded in classfiles v49) - and this code may appear useful
> >> if/when we are going to fix that...
> >> --
> >> Alexey
> >>
> >> 2006/9/21, Geir Magnusson Jr. <ge...@pobox.com>:
> >> > So do we fix it or scrap it?
> >> >
> >> > geir
> >> >
> >> > On Sep 20, 2006, at 10:23 AM, Ivan Volosyuk wrote:
> >> >
> >> > > This is an old code and it is unused for quite some time. Most
> >> likely
> >> > > it is broken.
> >> > > --
> >> > > Ivan
> >> > >
> >> > > On 9/20/06, Craig Zilles <zi...@cs.uiuc.edu> wrote:
> >> > >>
> >> > >> I noticed in the file trunk/vm/vmcore/src/util/
> >> > >> vm_strings.cpp there
> >> > >> is some code to support the storage of strings in arrays of (8b)
> >> > >> bytes rather than arrays of (16b) unsigned shorts. In the
> >> debugger,
> >> > >> I placed breakpoints in this code, and it was never active in
> >> my run.
> >> > >>
> >> > >> Can someone tell me the current status of this code and,
> >> > >> if it is
> >> > >> active, how I can turn it on? (From inspecting the source,
> >> it looked
> >> > >> inactive via hardcoding "false" on whether to compress the
> >> strings).
> >> > >> I might be interested in working on this code.
> >> > >
> >> > >
> >> ---------------------------------------------------------------------
> >> > > Terms of use : http://incubator.apache.org/harmony/mailing.html
> >> > > To unsubscribe, e-mail: harmony-dev-
> >> unsubscribe@incubator.apache.org
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> >> help@incubator.apache.org
> >> > >
> >> >
> >> >
> >> >
> >> ---------------------------------------------------------------------
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> >> >
> >> >
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> >>
> >>
> >
> >
> > --
> > Weldon Washburn
> > Intel Middleware Products Division
>
>
> ---------------------------------------------------------------------
> Terms of use : http://incubator.apache.org/harmony/mailing.html
> To unsubscribe, e-mail: harmony-dev-unsubscribe@incubator.apache.org
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>
>
--
Weldon Washburn
Intel Middleware Products Division
Re: question about support for compressed StringBuffers
Posted by Craig Zilles <zi...@cs.uiuc.edu>.
Okay, I'm going to be playing around with this code and other
approaches for "[C" compression.
Weldon -
you say:
> historically things like string compression make a difference to
> heap footprint and cache miss performance
do you know of other VMs that do this optimizations and if so if
there is any public documentation?
- Craig
On Sep 22, 2006, at 7:32 AM, Weldon Washburn wrote:
> hmm... I tried to putting a standard title on this email. It
> looks like we
> all suffer from too much email. So I repeat what I said earlier.
>
> All,
> I took a look at this code. I vote for keeping it. The reason is
> because
> Java is string intensive and historically things like string
> compression
> make a difference to heap footprint and cache miss performance.
> It looks
> like a significant amount of work has already been put in this code.
>
> Craig,
> It would be great if you can work on this code and get it going. I
> would be
> happy to work with you to get the mods committed to Harmony svn.
>
>
>
>
>
> On 9/22/06, Alexey Varlamov <al...@gmail.com> wrote:
>>
>> Just a thought:
>> DRLVM yet does not support 4-byte supplement characters of UTF8
>> (6-bytes encoded in classfiles v49) - and this code may appear useful
>> if/when we are going to fix that...
>> --
>> Alexey
>>
>> 2006/9/21, Geir Magnusson Jr. <ge...@pobox.com>:
>> > So do we fix it or scrap it?
>> >
>> > geir
>> >
>> > On Sep 20, 2006, at 10:23 AM, Ivan Volosyuk wrote:
>> >
>> > > This is an old code and it is unused for quite some time. Most
>> likely
>> > > it is broken.
>> > > --
>> > > Ivan
>> > >
>> > > On 9/20/06, Craig Zilles <zi...@cs.uiuc.edu> wrote:
>> > >>
>> > >> I noticed in the file trunk/vm/vmcore/src/util/
>> > >> vm_strings.cpp there
>> > >> is some code to support the storage of strings in arrays of (8b)
>> > >> bytes rather than arrays of (16b) unsigned shorts. In the
>> debugger,
>> > >> I placed breakpoints in this code, and it was never active in
>> my run.
>> > >>
>> > >> Can someone tell me the current status of this code and,
>> > >> if it is
>> > >> active, how I can turn it on? (From inspecting the source,
>> it looked
>> > >> inactive via hardcoding "false" on whether to compress the
>> strings).
>> > >> I might be interested in working on this code.
>> > >
>> > >
>> ---------------------------------------------------------------------
>> > > Terms of use : http://incubator.apache.org/harmony/mailing.html
>> > > To unsubscribe, e-mail: harmony-dev-
>> unsubscribe@incubator.apache.org
>> > > For additional commands, e-mail: harmony-dev-
>> help@incubator.apache.org
>> > >
>> >
>> >
>> >
>> ---------------------------------------------------------------------
>> > Terms of use : http://incubator.apache.org/harmony/mailing.html
>> > To unsubscribe, e-mail: harmony-dev-
>> unsubscribe@incubator.apache.org
>> > For additional commands, e-mail: harmony-dev-
>> help@incubator.apache.org
>> >
>> >
>>
>> ---------------------------------------------------------------------
>> Terms of use : http://incubator.apache.org/harmony/mailing.html
>> To unsubscribe, e-mail: harmony-dev-unsubscribe@incubator.apache.org
>> For additional commands, e-mail: harmony-dev-
>> help@incubator.apache.org
>>
>>
>
>
> --
> Weldon Washburn
> Intel Middleware Products Division
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Re: question about support for compressed StringBuffers
Posted by Weldon Washburn <we...@gmail.com>.
hmm... I tried to putting a standard title on this email. It looks like we
all suffer from too much email. So I repeat what I said earlier.
All,
I took a look at this code. I vote for keeping it. The reason is because
Java is string intensive and historically things like string compression
make a difference to heap footprint and cache miss performance. It looks
like a significant amount of work has already been put in this code.
Craig,
It would be great if you can work on this code and get it going. I would be
happy to work with you to get the mods committed to Harmony svn.
On 9/22/06, Alexey Varlamov <al...@gmail.com> wrote:
>
> Just a thought:
> DRLVM yet does not support 4-byte supplement characters of UTF8
> (6-bytes encoded in classfiles v49) - and this code may appear useful
> if/when we are going to fix that...
> --
> Alexey
>
> 2006/9/21, Geir Magnusson Jr. <ge...@pobox.com>:
> > So do we fix it or scrap it?
> >
> > geir
> >
> > On Sep 20, 2006, at 10:23 AM, Ivan Volosyuk wrote:
> >
> > > This is an old code and it is unused for quite some time. Most likely
> > > it is broken.
> > > --
> > > Ivan
> > >
> > > On 9/20/06, Craig Zilles <zi...@cs.uiuc.edu> wrote:
> > >>
> > >> I noticed in the file trunk/vm/vmcore/src/util/
> > >> vm_strings.cpp there
> > >> is some code to support the storage of strings in arrays of (8b)
> > >> bytes rather than arrays of (16b) unsigned shorts. In the debugger,
> > >> I placed breakpoints in this code, and it was never active in my run.
> > >>
> > >> Can someone tell me the current status of this code and,
> > >> if it is
> > >> active, how I can turn it on? (From inspecting the source, it looked
> > >> inactive via hardcoding "false" on whether to compress the strings).
> > >> I might be interested in working on this code.
> > >
> > > ---------------------------------------------------------------------
> > > Terms of use : http://incubator.apache.org/harmony/mailing.html
> > > To unsubscribe, e-mail: harmony-dev-unsubscribe@incubator.apache.org
> > > For additional commands, e-mail: harmony-dev-help@incubator.apache.org
> > >
> >
> >
> > ---------------------------------------------------------------------
> > Terms of use : http://incubator.apache.org/harmony/mailing.html
> > To unsubscribe, e-mail: harmony-dev-unsubscribe@incubator.apache.org
> > For additional commands, e-mail: harmony-dev-help@incubator.apache.org
> >
> >
>
> ---------------------------------------------------------------------
> Terms of use : http://incubator.apache.org/harmony/mailing.html
> To unsubscribe, e-mail: harmony-dev-unsubscribe@incubator.apache.org
> For additional commands, e-mail: harmony-dev-help@incubator.apache.org
>
>
--
Weldon Washburn
Intel Middleware Products Division
Re: question about support for compressed StringBuffers
Posted by Alexey Varlamov <al...@gmail.com>.
Just a thought:
DRLVM yet does not support 4-byte supplement characters of UTF8
(6-bytes encoded in classfiles v49) - and this code may appear useful
if/when we are going to fix that...
--
Alexey
2006/9/21, Geir Magnusson Jr. <ge...@pobox.com>:
> So do we fix it or scrap it?
>
> geir
>
> On Sep 20, 2006, at 10:23 AM, Ivan Volosyuk wrote:
>
> > This is an old code and it is unused for quite some time. Most likely
> > it is broken.
> > --
> > Ivan
> >
> > On 9/20/06, Craig Zilles <zi...@cs.uiuc.edu> wrote:
> >>
> >> I noticed in the file trunk/vm/vmcore/src/util/
> >> vm_strings.cpp there
> >> is some code to support the storage of strings in arrays of (8b)
> >> bytes rather than arrays of (16b) unsigned shorts. In the debugger,
> >> I placed breakpoints in this code, and it was never active in my run.
> >>
> >> Can someone tell me the current status of this code and,
> >> if it is
> >> active, how I can turn it on? (From inspecting the source, it looked
> >> inactive via hardcoding "false" on whether to compress the strings).
> >> I might be interested in working on this code.
> >
> > ---------------------------------------------------------------------
> > Terms of use : http://incubator.apache.org/harmony/mailing.html
> > To unsubscribe, e-mail: harmony-dev-unsubscribe@incubator.apache.org
> > For additional commands, e-mail: harmony-dev-help@incubator.apache.org
> >
>
>
> ---------------------------------------------------------------------
> Terms of use : http://incubator.apache.org/harmony/mailing.html
> To unsubscribe, e-mail: harmony-dev-unsubscribe@incubator.apache.org
> For additional commands, e-mail: harmony-dev-help@incubator.apache.org
>
>
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Re: question about support for compressed StringBuffers
Posted by "Geir Magnusson Jr." <ge...@pobox.com>.
So do we fix it or scrap it?
geir
On Sep 20, 2006, at 10:23 AM, Ivan Volosyuk wrote:
> This is an old code and it is unused for quite some time. Most likely
> it is broken.
> --
> Ivan
>
> On 9/20/06, Craig Zilles <zi...@cs.uiuc.edu> wrote:
>>
>> I noticed in the file trunk/vm/vmcore/src/util/
>> vm_strings.cpp there
>> is some code to support the storage of strings in arrays of (8b)
>> bytes rather than arrays of (16b) unsigned shorts. In the debugger,
>> I placed breakpoints in this code, and it was never active in my run.
>>
>> Can someone tell me the current status of this code and,
>> if it is
>> active, how I can turn it on? (From inspecting the source, it looked
>> inactive via hardcoding "false" on whether to compress the strings).
>> I might be interested in working on this code.
>
> ---------------------------------------------------------------------
> Terms of use : http://incubator.apache.org/harmony/mailing.html
> To unsubscribe, e-mail: harmony-dev-unsubscribe@incubator.apache.org
> For additional commands, e-mail: harmony-dev-help@incubator.apache.org
>
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Re: question about support for compressed StringBuffers
Posted by Ivan Volosyuk <iv...@gmail.com>.
This is an old code and it is unused for quite some time. Most likely
it is broken.
--
Ivan
On 9/20/06, Craig Zilles <zi...@cs.uiuc.edu> wrote:
>
> I noticed in the file trunk/vm/vmcore/src/util/vm_strings.cpp there
> is some code to support the storage of strings in arrays of (8b)
> bytes rather than arrays of (16b) unsigned shorts. In the debugger,
> I placed breakpoints in this code, and it was never active in my run.
>
> Can someone tell me the current status of this code and, if it is
> active, how I can turn it on? (From inspecting the source, it looked
> inactive via hardcoding "false" on whether to compress the strings).
> I might be interested in working on this code.
---------------------------------------------------------------------
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To unsubscribe, e-mail: harmony-dev-unsubscribe@incubator.apache.org
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