Re: [rvm-research] online turning on/off write barriers

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Thanks Richard! This is very relevant. Too sad, they did not use Jikes =
RVM ;)

> On Jan 9, 2019, at 5:19 PM, Richard Jones <[email protected]> =
wrote:
>=20
>=20
>=20
> Eliot Moss wrote on 09/01/2019 15:51:
>> On 1/9/2019 9:48 AM, Shoaib Akram wrote:
>>=20
>>> As part of my research, I want to build a JVM prototype, which =
enables
>>   executing certain phases of the program using write barriers (both =
primitive
>>   and references), and other phases without write barriers. The write =
barrier
>>   will do some accounting, for example, set a special bit the object
>>   header. Generally, you can build the JVM with write barriers =
enabled or
>>   disabled. My idea is to use the benefit of the write barrier to =
online
>>   monitor certain activities, whereas not pay the penalty of having =
the
>>   barriers turned on during the entire program execution. Note that =
dividing
>>   the barrier into a fast path (check a flag and leave the barrier), =
and a
>>   slow path (check a flag and do the accounting) is not very helpful =
since the
>>   cost of the extra method call(s) when barriers are enabled is
>>   prohibitive. The cost of accounting (setting bit in header) is a =
fraction of
>>   the total cost of enabling the write barriers.
>>=20
>>> One way to accomplish this is to recompile all methods while =
informing the
>>   compiler(s) to insert or leave the write barrier code. Has anyone =
tried
>>   doing such a thing in the past? Any thoughts on alternative ways or
>>   challenges involved are welcome!
>>=20
>> Unless turning the barriers on/off is a very rare event, the =
recompilation
>> cost may well be an issue in itself.
>>=20
>> Fast path/slow path is not an either/or kind of thing.  You can move =
more code
>> into the fast path, for example.  So if your accounting is simple, =
you just
>> inline it there.  You still need your check as to whether barriers =
are on/off.
>> That can be a check of a memory location, or, if you can dedicate one =
bit in a
>> register somewhere, you can make the test faster (though more complex =
to turn
>> on/off).
>>=20
>> I suppose another option is to retain *both* versions of methods, and =
swap
>> them in and out.  You would need to do on-stack replacement of =
currently
>> running methods in that case -- something that has been done, but is =
somewhat
>> complex (unless you can just use it more or less as is).
>=20
> Phil Pizlo, Erez Petrank and Bjarne Steensgaard did this, but for =
Bartok not Jikes RVM. See
>=20
> @inproceedings{pizl08a,
> title =3D {Path Specialization: Reducing Phased Execution Overheads},
> author =3D {Filip Pizlo and Erez Petrank and Bjarne Steensgaard},
> crossref =3D {ISMM08},
> pages =3D {81--90},
> doi =3D {10.1145/1375634.1375647},
> abstract =3D {As garbage collected languages become widely used, the
> quest for reducing collection overheads becomes essential. In this
> paper, we propose a compiler optimization called path specialization
> that shrinks the cost of memory barriers for a wide variety of
> garbage collectors including concurrent, incremental, and real-time
> collectors. Path specialization provides a non-trivial decrease in
> write-barrier overheads and a drastic reduction of read-barrier
> overheads. It is effective when used with collectors that go through
> various phases each employing a different barrier behavior, and is
> most effective for collectors that have an idle phase, in which no
> barrier activity is required. We have implemented path specialization
> in the Bartok compiler and runtime for C# and tested it with
> state-of-the-art concurrent and real-time collectors, demonstrating
> its efficacy.}
> }
>=20
>>=20
>> You might also check into the lterature about turning various =
instrumentation
>> on and off by recompiling methods dynamically, to sample only =
sometimes.  Do
>> you need this accounting barrier turned on/off for all objects at =
once? Or
>> are you just trying to sample such that turning it on/off for =
different
>> methods at different time would be ok?  Etc.
>>=20
>> Btw, we usually find that we can be more helpful on this list if you =
tell us
>> more about what you're really trying to accomplish :-) ...
>>=20
>> Regards - Eliot Moss
>>=20
>>=20
>> _______________________________________________
>> Jikesrvm-researchers mailing list
>> [email protected]
>> https://lists.sourceforge.net/lists/listinfo/jikesrvm-researchers
>=20
>=20
>=20
> _______________________________________________
> Jikesrvm-researchers mailing list
> [email protected] =
<mailto:[email protected]>
> https://lists.sourceforge.net/lists/listinfo/jikesrvm-researchers =
<https://lists.sourceforge.net/lists/listinfo/jikesrvm-researchers>

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<html><head><meta http-equiv=3D"Content-Type" content=3D"text/html; =
charset=3Dus-ascii"></head><body style=3D"word-wrap: break-word; =
-webkit-nbsp-mode: space; line-break: after-white-space;" =
class=3D"">Thanks Richard! This is very relevant. Too sad, they did not =
use Jikes RVM ;)<br class=3D""><div><br class=3D""><blockquote =
type=3D"cite" class=3D""><div class=3D"">On Jan 9, 2019, at 5:19 PM, =
Richard Jones &lt;<a href=3D"mailto:[email protected]" =
class=3D"">[email protected]</a>&gt; wrote:</div><br =
class=3D"Apple-interchange-newline"><div class=3D""><br =
style=3D"caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: =
18px; font-style: normal; font-variant-caps: normal; font-weight: =
normal; letter-spacing: normal; text-align: start; text-indent: 0px; =
text-transform: none; white-space: normal; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; text-decoration: none;" class=3D""><br =
style=3D"caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: =
18px; font-style: normal; font-variant-caps: normal; font-weight: =
normal; letter-spacing: normal; text-align: start; text-indent: 0px; =
text-transform: none; white-space: normal; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; text-decoration: none;" class=3D""><span =
style=3D"caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: =
18px; font-style: normal; font-variant-caps: normal; font-weight: =
normal; letter-spacing: normal; text-align: start; text-indent: 0px; =
text-transform: none; white-space: normal; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; text-decoration: none; float: none; =
display: inline !important;" class=3D"">Eliot Moss wrote on 09/01/2019 =
15:51:</span><br style=3D"caret-color: rgb(0, 0, 0); font-family: =
Helvetica; font-size: 18px; font-style: normal; font-variant-caps: =
normal; font-weight: normal; letter-spacing: normal; text-align: start; =
text-indent: 0px; text-transform: none; white-space: normal; =
word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: =
none;" class=3D""><blockquote type=3D"cite" style=3D"font-family: =
Helvetica; font-size: 18px; font-style: normal; font-variant-caps: =
normal; font-weight: normal; letter-spacing: normal; orphans: auto; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; =
-webkit-text-stroke-width: 0px; text-decoration: none;" class=3D"">On =
1/9/2019 9:48 AM, Shoaib Akram wrote:<br class=3D""><br =
class=3D""><blockquote type=3D"cite" class=3D"">As part of my research, =
I want to build a JVM prototype, which enables<br =
class=3D""></blockquote>&nbsp;<span =
class=3D"Apple-converted-space">&nbsp;</span>executing certain phases of =
the program using write barriers (both primitive<br class=3D"">&nbsp;<span=
 class=3D"Apple-converted-space">&nbsp;</span>and references), and other =
phases without write barriers. The write barrier<br class=3D"">&nbsp;<span=
 class=3D"Apple-converted-space">&nbsp;</span>will do some accounting, =
for example, set a special bit the object<br class=3D"">&nbsp;<span =
class=3D"Apple-converted-space">&nbsp;</span>header. Generally, you can =
build the JVM with write barriers enabled or<br class=3D"">&nbsp;<span =
class=3D"Apple-converted-space">&nbsp;</span>disabled. My idea is to use =
the benefit of the write barrier to online<br class=3D"">&nbsp;<span =
class=3D"Apple-converted-space">&nbsp;</span>monitor certain activities, =
whereas not pay the penalty of having the<br class=3D"">&nbsp;<span =
class=3D"Apple-converted-space">&nbsp;</span>barriers turned on during =
the entire program execution. Note that dividing<br class=3D"">&nbsp;<span=
 class=3D"Apple-converted-space">&nbsp;</span>the barrier into a fast =
path (check a flag and leave the barrier), and a<br class=3D"">&nbsp;<span=
 class=3D"Apple-converted-space">&nbsp;</span>slow path (check a flag =
and do the accounting) is not very helpful since the<br =
class=3D"">&nbsp;<span class=3D"Apple-converted-space">&nbsp;</span>cost =
of the extra method call(s) when barriers are enabled is<br =
class=3D"">&nbsp;<span =
class=3D"Apple-converted-space">&nbsp;</span>prohibitive. The cost of =
accounting (setting bit in header) is a fraction of<br =
class=3D"">&nbsp;<span class=3D"Apple-converted-space">&nbsp;</span>the =
total cost of enabling the write barriers.<br class=3D""><br =
class=3D""><blockquote type=3D"cite" class=3D"">One way to accomplish =
this is to recompile all methods while informing the<br =
class=3D""></blockquote>&nbsp;<span =
class=3D"Apple-converted-space">&nbsp;</span>compiler(s) to insert or =
leave the write barrier code. Has anyone tried<br class=3D"">&nbsp;<span =
class=3D"Apple-converted-space">&nbsp;</span>doing such a thing in the =
past? Any thoughts on alternative ways or<br class=3D"">&nbsp;<span =
class=3D"Apple-converted-space">&nbsp;</span>challenges involved are =
welcome!<br class=3D""><br class=3D"">Unless turning the barriers on/off =
is a very rare event, the recompilation<br class=3D"">cost may well be =
an issue in itself.<br class=3D""><br class=3D"">Fast path/slow path is =
not an either/or kind of thing.&nbsp; You can move more code<br =
class=3D"">into the fast path, for example.&nbsp; So if your accounting =
is simple, you just<br class=3D"">inline it there.&nbsp; You still need =
your check as to whether barriers are on/off.<br class=3D"">That can be =
a check of a memory location, or, if you can dedicate one bit in a<br =
class=3D"">register somewhere, you can make the test faster (though more =
complex to turn<br class=3D"">on/off).<br class=3D""><br class=3D"">I =
suppose another option is to retain *both* versions of methods, and =
swap<br class=3D"">them in and out.&nbsp; You would need to do on-stack =
replacement of currently<br class=3D"">running methods in that case -- =
something that has been done, but is somewhat<br class=3D"">complex =
(unless you can just use it more or less as is).<br =
class=3D""></blockquote><br style=3D"caret-color: rgb(0, 0, 0); =
font-family: Helvetica; font-size: 18px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none;" class=3D""><span style=3D"caret-color: rgb(0, 0, =
0); font-family: Helvetica; font-size: 18px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none; float: none; display: inline !important;" =
class=3D"">Phil Pizlo, Erez Petrank and Bjarne Steensgaard did this, but =
for Bartok not Jikes RVM. See</span><br style=3D"caret-color: rgb(0, 0, =
0); font-family: Helvetica; font-size: 18px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none;" class=3D""><br style=3D"caret-color: rgb(0, 0, =
0); font-family: Helvetica; font-size: 18px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none;" class=3D""><span style=3D"caret-color: rgb(0, 0, =
0); font-family: Helvetica; font-size: 18px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none; float: none; display: inline !important;" =
class=3D"">@inproceedings{pizl08a,</span><br style=3D"caret-color: =
rgb(0, 0, 0); font-family: Helvetica; font-size: 18px; font-style: =
normal; font-variant-caps: normal; font-weight: normal; letter-spacing: =
normal; text-align: start; text-indent: 0px; text-transform: none; =
white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none;" class=3D""><span style=3D"caret-color: rgb(0, 0, =
0); font-family: Helvetica; font-size: 18px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none; float: none; display: inline !important;" =
class=3D"">title =3D {Path Specialization: Reducing Phased Execution =
Overheads},</span><br style=3D"caret-color: rgb(0, 0, 0); font-family: =
Helvetica; font-size: 18px; font-style: normal; font-variant-caps: =
normal; font-weight: normal; letter-spacing: normal; text-align: start; =
text-indent: 0px; text-transform: none; white-space: normal; =
word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: =
none;" class=3D""><span style=3D"caret-color: rgb(0, 0, 0); font-family: =
Helvetica; font-size: 18px; font-style: normal; font-variant-caps: =
normal; font-weight: normal; letter-spacing: normal; text-align: start; =
text-indent: 0px; text-transform: none; white-space: normal; =
word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: =
none; float: none; display: inline !important;" class=3D"">author =3D =
{Filip Pizlo and Erez Petrank and Bjarne Steensgaard},</span><br =
style=3D"caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: =
18px; font-style: normal; font-variant-caps: normal; font-weight: =
normal; letter-spacing: normal; text-align: start; text-indent: 0px; =
text-transform: none; white-space: normal; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; text-decoration: none;" class=3D""><span =
style=3D"caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: =
18px; font-style: normal; font-variant-caps: normal; font-weight: =
normal; letter-spacing: normal; text-align: start; text-indent: 0px; =
text-transform: none; white-space: normal; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; text-decoration: none; float: none; =
display: inline !important;" class=3D"">crossref =3D {ISMM08},</span><br =
style=3D"caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: =
18px; font-style: normal; font-variant-caps: normal; font-weight: =
normal; letter-spacing: normal; text-align: start; text-indent: 0px; =
text-transform: none; white-space: normal; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; text-decoration: none;" class=3D""><span =
style=3D"caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: =
18px; font-style: normal; font-variant-caps: normal; font-weight: =
normal; letter-spacing: normal; text-align: start; text-indent: 0px; =
text-transform: none; white-space: normal; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; text-decoration: none; float: none; =
display: inline !important;" class=3D"">pages =3D {81--90},</span><br =
style=3D"caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: =
18px; font-style: normal; font-variant-caps: normal; font-weight: =
normal; letter-spacing: normal; text-align: start; text-indent: 0px; =
text-transform: none; white-space: normal; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; text-decoration: none;" class=3D""><span =
style=3D"caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: =
18px; font-style: normal; font-variant-caps: normal; font-weight: =
normal; letter-spacing: normal; text-align: start; text-indent: 0px; =
text-transform: none; white-space: normal; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; text-decoration: none; float: none; =
display: inline !important;" class=3D"">doi =3D =
{10.1145/1375634.1375647},</span><br style=3D"caret-color: rgb(0, 0, 0); =
font-family: Helvetica; font-size: 18px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none;" class=3D""><span style=3D"caret-color: rgb(0, 0, =
0); font-family: Helvetica; font-size: 18px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none; float: none; display: inline !important;" =
class=3D"">abstract =3D {As garbage collected languages become widely =
used, the</span><br style=3D"caret-color: rgb(0, 0, 0); font-family: =
Helvetica; font-size: 18px; font-style: normal; font-variant-caps: =
normal; font-weight: normal; letter-spacing: normal; text-align: start; =
text-indent: 0px; text-transform: none; white-space: normal; =
word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: =
none;" class=3D""><span style=3D"caret-color: rgb(0, 0, 0); font-family: =
Helvetica; font-size: 18px; font-style: normal; font-variant-caps: =
normal; font-weight: normal; letter-spacing: normal; text-align: start; =
text-indent: 0px; text-transform: none; white-space: normal; =
word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: =
none; float: none; display: inline !important;" class=3D"">quest for =
reducing collection overheads becomes essential. In this</span><br =
style=3D"caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: =
18px; font-style: normal; font-variant-caps: normal; font-weight: =
normal; letter-spacing: normal; text-align: start; text-indent: 0px; =
text-transform: none; white-space: normal; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; text-decoration: none;" class=3D""><span =
style=3D"caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: =
18px; font-style: normal; font-variant-caps: normal; font-weight: =
normal; letter-spacing: normal; text-align: start; text-indent: 0px; =
text-transform: none; white-space: normal; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; text-decoration: none; float: none; =
display: inline !important;" class=3D"">paper, we propose a compiler =
optimization called path specialization</span><br style=3D"caret-color: =
rgb(0, 0, 0); font-family: Helvetica; font-size: 18px; font-style: =
normal; font-variant-caps: normal; font-weight: normal; letter-spacing: =
normal; text-align: start; text-indent: 0px; text-transform: none; =
white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none;" class=3D""><span style=3D"caret-color: rgb(0, 0, =
0); font-family: Helvetica; font-size: 18px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none; float: none; display: inline !important;" =
class=3D"">that shrinks the cost of memory barriers for a wide variety =
of</span><br style=3D"caret-color: rgb(0, 0, 0); font-family: Helvetica; =
font-size: 18px; font-style: normal; font-variant-caps: normal; =
font-weight: normal; letter-spacing: normal; text-align: start; =
text-indent: 0px; text-transform: none; white-space: normal; =
word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: =
none;" class=3D""><span style=3D"caret-color: rgb(0, 0, 0); font-family: =
Helvetica; font-size: 18px; font-style: normal; font-variant-caps: =
normal; font-weight: normal; letter-spacing: normal; text-align: start; =
text-indent: 0px; text-transform: none; white-space: normal; =
word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: =
none; float: none; display: inline !important;" class=3D"">garbage =
collectors including concurrent, incremental, and real-time</span><br =
style=3D"caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: =
18px; font-style: normal; font-variant-caps: normal; font-weight: =
normal; letter-spacing: normal; text-align: start; text-indent: 0px; =
text-transform: none; white-space: normal; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; text-decoration: none;" class=3D""><span =
style=3D"caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: =
18px; font-style: normal; font-variant-caps: normal; font-weight: =
normal; letter-spacing: normal; text-align: start; text-indent: 0px; =
text-transform: none; white-space: normal; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; text-decoration: none; float: none; =
display: inline !important;" class=3D"">collectors. Path specialization =
provides a non-trivial decrease in</span><br style=3D"caret-color: =
rgb(0, 0, 0); font-family: Helvetica; font-size: 18px; font-style: =
normal; font-variant-caps: normal; font-weight: normal; letter-spacing: =
normal; text-align: start; text-indent: 0px; text-transform: none; =
white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none;" class=3D""><span style=3D"caret-color: rgb(0, 0, =
0); font-family: Helvetica; font-size: 18px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none; float: none; display: inline !important;" =
class=3D"">write-barrier overheads and a drastic reduction of =
read-barrier</span><br style=3D"caret-color: rgb(0, 0, 0); font-family: =
Helvetica; font-size: 18px; font-style: normal; font-variant-caps: =
normal; font-weight: normal; letter-spacing: normal; text-align: start; =
text-indent: 0px; text-transform: none; white-space: normal; =
word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: =
none;" class=3D""><span style=3D"caret-color: rgb(0, 0, 0); font-family: =
Helvetica; font-size: 18px; font-style: normal; font-variant-caps: =
normal; font-weight: normal; letter-spacing: normal; text-align: start; =
text-indent: 0px; text-transform: none; white-space: normal; =
word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: =
none; float: none; display: inline !important;" class=3D"">overheads. It =
is effective when used with collectors that go through</span><br =
style=3D"caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: =
18px; font-style: normal; font-variant-caps: normal; font-weight: =
normal; letter-spacing: normal; text-align: start; text-indent: 0px; =
text-transform: none; white-space: normal; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; text-decoration: none;" class=3D""><span =
style=3D"caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: =
18px; font-style: normal; font-variant-caps: normal; font-weight: =
normal; letter-spacing: normal; text-align: start; text-indent: 0px; =
text-transform: none; white-space: normal; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; text-decoration: none; float: none; =
display: inline !important;" class=3D"">various phases each employing a =
different barrier behavior, and is</span><br style=3D"caret-color: =
rgb(0, 0, 0); font-family: Helvetica; font-size: 18px; font-style: =
normal; font-variant-caps: normal; font-weight: normal; letter-spacing: =
normal; text-align: start; text-indent: 0px; text-transform: none; =
white-space: normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none;" class=3D""><span style=3D"caret-color: rgb(0, 0, =
0); font-family: Helvetica; font-size: 18px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none; float: none; display: inline !important;" =
class=3D"">most effective for collectors that have an idle phase, in =
which no</span><br style=3D"caret-color: rgb(0, 0, 0); font-family: =
Helvetica; font-size: 18px; font-style: normal; font-variant-caps: =
normal; font-weight: normal; letter-spacing: normal; text-align: start; =
text-indent: 0px; text-transform: none; white-space: normal; =
word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: =
none;" class=3D""><span style=3D"caret-color: rgb(0, 0, 0); font-family: =
Helvetica; font-size: 18px; font-style: normal; font-variant-caps: =
normal; font-weight: normal; letter-spacing: normal; text-align: start; =
text-indent: 0px; text-transform: none; white-space: normal; =
word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: =
none; float: none; display: inline !important;" class=3D"">barrier =
activity is required. We have implemented path specialization</span><br =
style=3D"caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: =
18px; font-style: normal; font-variant-caps: normal; font-weight: =
normal; letter-spacing: normal; text-align: start; text-indent: 0px; =
text-transform: none; white-space: normal; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; text-decoration: none;" class=3D""><span =
style=3D"caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: =
18px; font-style: normal; font-variant-caps: normal; font-weight: =
normal; letter-spacing: normal; text-align: start; text-indent: 0px; =
text-transform: none; white-space: normal; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; text-decoration: none; float: none; =
display: inline !important;" class=3D"">in the Bartok compiler and =
runtime for C# and tested it with</span><br style=3D"caret-color: rgb(0, =
0, 0); font-family: Helvetica; font-size: 18px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none;" class=3D""><span style=3D"caret-color: rgb(0, 0, =
0); font-family: Helvetica; font-size: 18px; font-style: normal; =
font-variant-caps: normal; font-weight: normal; letter-spacing: normal; =
text-align: start; text-indent: 0px; text-transform: none; white-space: =
normal; word-spacing: 0px; -webkit-text-stroke-width: 0px; =
text-decoration: none; float: none; display: inline !important;" =
class=3D"">state-of-the-art concurrent and real-time collectors, =
demonstrating</span><br style=3D"caret-color: rgb(0, 0, 0); font-family: =
Helvetica; font-size: 18px; font-style: normal; font-variant-caps: =
normal; font-weight: normal; letter-spacing: normal; text-align: start; =
text-indent: 0px; text-transform: none; white-space: normal; =
word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: =
none;" class=3D""><span style=3D"caret-color: rgb(0, 0, 0); font-family: =
Helvetica; font-size: 18px; font-style: normal; font-variant-caps: =
normal; font-weight: normal; letter-spacing: normal; text-align: start; =
text-indent: 0px; text-transform: none; white-space: normal; =
word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: =
none; float: none; display: inline !important;" class=3D"">its =
efficacy.}</span><br style=3D"caret-color: rgb(0, 0, 0); font-family: =
Helvetica; font-size: 18px; font-style: normal; font-variant-caps: =
normal; font-weight: normal; letter-spacing: normal; text-align: start; =
text-indent: 0px; text-transform: none; white-space: normal; =
word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: =
none;" class=3D""><span style=3D"caret-color: rgb(0, 0, 0); font-family: =
Helvetica; font-size: 18px; font-style: normal; font-variant-caps: =
normal; font-weight: normal; letter-spacing: normal; text-align: start; =
text-indent: 0px; text-transform: none; white-space: normal; =
word-spacing: 0px; -webkit-text-stroke-width: 0px; text-decoration: =
none; float: none; display: inline !important;" class=3D"">}</span><br =
style=3D"caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: =
18px; font-style: normal; font-variant-caps: normal; font-weight: =
normal; letter-spacing: normal; text-align: start; text-indent: 0px; =
text-transform: none; white-space: normal; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; text-decoration: none;" class=3D""><br =
style=3D"caret-color: rgb(0, 0, 0); font-family: Helvetica; font-size: =
18px; font-style: normal; font-variant-caps: normal; font-weight: =
normal; letter-spacing: normal; text-align: start; text-indent: 0px; =
text-transform: none; white-space: normal; word-spacing: 0px; =
-webkit-text-stroke-width: 0px; text-decoration: none;" =
class=3D""><blockquote type=3D"cite" style=3D"font-family: Helvetica; =
font-size: 18px; font-style: normal; font-variant-caps: normal; =
font-weight: normal; letter-spacing: normal; orphans: auto; text-align: =
start; text-indent: 0px; text-transform: none; white-space: normal; =
widows: auto; word-spacing: 0px; -webkit-text-size-adjust: auto; =
-webkit-text-stroke-width: 0px; text-decoration: none;" class=3D""><br =
class=3D"">You might also check into the lterature about turning various =
instrumentation<br class=3D"">on and off by recompiling methods =
dynamically, to sample only sometimes.&nbsp; Do<br class=3D"">you need =
this accounting barrier turned on/off for all objects at once? Or<br =
class=3D"">are you just trying to sample such that turning it on/off for =
different<br class=3D"">methods at different time would be ok?&nbsp; =
Etc.<br class=3D""><br class=3D"">Btw, we usually find that we can be =
more helpful on this list if you tell us<br class=3D"">more about what =
you're really trying to accomplish :-) ...<br class=3D""><br =
class=3D"">Regards - Eliot Moss<br class=3D""><br class=3D""><br =
class=3D"">_______________________________________________<br =
class=3D"">Jikesrvm-researchers mailing list<br class=3D""><a =
href=3D"mailto:[email protected]" =
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font-family: Helvetica; font-size: 18px; font-style: normal; =
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text-decoration: none; float: none; display: inline !important;" =
class=3D"">_______________________________________________</span><br =
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