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Posted to dev@jmeter.apache.org by Felix Schumacher <fe...@internetallee.de> on 2015/01/25 22:30:05 UTC
Re: svn commit: r1654701 - /jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java
Am 25. Januar 2015 21:35:48 MEZ, schrieb pmouawad@apache.org:
>Author: pmouawad
>Date: Sun Jan 25 20:35:48 2015
>New Revision: 1654701
>
>URL: http://svn.apache.org/r1654701
>Log:
>Remove unused fields
>
>Modified:
> jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java
>
>Modified:
>jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java
>URL:
>http://svn.apache.org/viewvc/jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java?rev=1654701&r1=1654700&r2=1654701&view=diff
>==============================================================================
>--- jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java
>(original)
>+++ jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java
>Sun Jan 25 20:35:48 2015
>@@ -54,11 +54,6 @@ public class ThreadLocalRandom extends R
> */
> boolean initialized;
>
>- // Padding to help avoid memory contention among seed updates in
>- // different TLRs in the common case that they are located near
>- // each other.
>- private long pad0, pad1, pad2, pad3, pad4, pad5, pad6, pad7;
Given the comment above the fields, I would not remove those padding fields.
Regards
Felix
>-
> /**
> * The actual ThreadLocal
> */
Re: svn commit: r1654701 - /jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java
Posted by Antonio Gomes Rodrigues <ra...@gmail.com>.
Hi,
In modern JVM it's useless because it remove dead code.
This technique is use in C/C++ in mechanical sympathy (to be friendly with
cpu cache to avoid to much context switch in it)
Antonio
2015-01-26 21:16 GMT+01:00 Philippe Mouawad <ph...@gmail.com>:
> Hi,
> Thanks for infos.
>
> By the way I noticed netty had a variation of this class in their code
> which inits seed differently.
>
> Regards
>
>
>
> On Mon, Jan 26, 2015 at 7:28 AM, Felix Schumacher <
> felix.schumacher@internetallee.de> wrote:
>
> >
> >
> > Hi Phillipe.
> >
> > Am 25. Januar 2015 22:42:27 MEZ, schrieb Philippe Mouawad <
> > philippe.mouawad@gmail.com>:
> > >Hi Felix,
> > >Reverted , can you explain to me this ? I don't see these fields used,
> > >are
> > >they through reflection ?
> >
> > They are not used. Neither directly nor indirectly. They are used as
> > padding to prevent cache issues on hardware level. You will find more
> > information when you search the Internet for "ThreadLocalRandom padding".
> >
> > It might be, that we don't need the padding on modern jvms, but if we
> > assumed to have those, we would not need the copy of the class either :)
> >
> > That is why I opt for keeping the "useless" variables.
> >
> > Regards
> > Felix
> > >
> > >Thanks
> > >
> > >On Sun, Jan 25, 2015 at 10:30 PM, Felix Schumacher <
> > >felix.schumacher@internetallee.de> wrote:
> > >
> > >>
> > >>
> > >> Am 25. Januar 2015 21:35:48 MEZ, schrieb pmouawad@apache.org:
> > >> >Author: pmouawad
> > >> >Date: Sun Jan 25 20:35:48 2015
> > >> >New Revision: 1654701
> > >> >
> > >> >URL: http://svn.apache.org/r1654701
> > >> >Log:
> > >> >Remove unused fields
> > >> >
> > >> >Modified:
> > >> >
> > >jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java
> > >> >
> > >> >Modified:
> > >> >jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java
> > >> >URL:
> > >> >
> > >>
> > >
> >
> http://svn.apache.org/viewvc/jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java?rev=1654701&r1=1654700&r2=1654701&view=diff
> > >>
> > >>
> >
> >
> >>==============================================================================
> > >> >---
> > >jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java
> > >> >(original)
> > >> >+++
> > >jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java
> > >> >Sun Jan 25 20:35:48 2015
> > >> >@@ -54,11 +54,6 @@ public class ThreadLocalRandom extends R
> > >> > */
> > >> > boolean initialized;
> > >> >
> > >> >- // Padding to help avoid memory contention among seed updates
> > >in
> > >> >- // different TLRs in the common case that they are located near
> > >> >- // each other.
> > >> >- private long pad0, pad1, pad2, pad3, pad4, pad5, pad6, pad7;
> > >>
> > >> Given the comment above the fields, I would not remove those padding
> > >> fields.
> > >>
> > >> Regards
> > >> Felix
> > >> >-
> > >> > /**
> > >> > * The actual ThreadLocal
> > >> > */
> > >>
> > >>
> >
> >
>
>
> --
> Cordialement.
> Philippe Mouawad.
>
Re: svn commit: r1654701 - /jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java
Posted by Philippe Mouawad <ph...@gmail.com>.
Hi,
Thanks for infos.
By the way I noticed netty had a variation of this class in their code
which inits seed differently.
Regards
On Mon, Jan 26, 2015 at 7:28 AM, Felix Schumacher <
felix.schumacher@internetallee.de> wrote:
>
>
> Hi Phillipe.
>
> Am 25. Januar 2015 22:42:27 MEZ, schrieb Philippe Mouawad <
> philippe.mouawad@gmail.com>:
> >Hi Felix,
> >Reverted , can you explain to me this ? I don't see these fields used,
> >are
> >they through reflection ?
>
> They are not used. Neither directly nor indirectly. They are used as
> padding to prevent cache issues on hardware level. You will find more
> information when you search the Internet for "ThreadLocalRandom padding".
>
> It might be, that we don't need the padding on modern jvms, but if we
> assumed to have those, we would not need the copy of the class either :)
>
> That is why I opt for keeping the "useless" variables.
>
> Regards
> Felix
> >
> >Thanks
> >
> >On Sun, Jan 25, 2015 at 10:30 PM, Felix Schumacher <
> >felix.schumacher@internetallee.de> wrote:
> >
> >>
> >>
> >> Am 25. Januar 2015 21:35:48 MEZ, schrieb pmouawad@apache.org:
> >> >Author: pmouawad
> >> >Date: Sun Jan 25 20:35:48 2015
> >> >New Revision: 1654701
> >> >
> >> >URL: http://svn.apache.org/r1654701
> >> >Log:
> >> >Remove unused fields
> >> >
> >> >Modified:
> >> >
> >jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java
> >> >
> >> >Modified:
> >> >jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java
> >> >URL:
> >> >
> >>
> >
> http://svn.apache.org/viewvc/jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java?rev=1654701&r1=1654700&r2=1654701&view=diff
> >>
> >>
>
> >>==============================================================================
> >> >---
> >jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java
> >> >(original)
> >> >+++
> >jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java
> >> >Sun Jan 25 20:35:48 2015
> >> >@@ -54,11 +54,6 @@ public class ThreadLocalRandom extends R
> >> > */
> >> > boolean initialized;
> >> >
> >> >- // Padding to help avoid memory contention among seed updates
> >in
> >> >- // different TLRs in the common case that they are located near
> >> >- // each other.
> >> >- private long pad0, pad1, pad2, pad3, pad4, pad5, pad6, pad7;
> >>
> >> Given the comment above the fields, I would not remove those padding
> >> fields.
> >>
> >> Regards
> >> Felix
> >> >-
> >> > /**
> >> > * The actual ThreadLocal
> >> > */
> >>
> >>
>
>
--
Cordialement.
Philippe Mouawad.
Re: svn commit: r1654701 - /jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java
Posted by Felix Schumacher <fe...@internetallee.de>.
Hi Phillipe.
Am 25. Januar 2015 22:42:27 MEZ, schrieb Philippe Mouawad <ph...@gmail.com>:
>Hi Felix,
>Reverted , can you explain to me this ? I don't see these fields used,
>are
>they through reflection ?
They are not used. Neither directly nor indirectly. They are used as padding to prevent cache issues on hardware level. You will find more information when you search the Internet for "ThreadLocalRandom padding".
It might be, that we don't need the padding on modern jvms, but if we assumed to have those, we would not need the copy of the class either :)
That is why I opt for keeping the "useless" variables.
Regards
Felix
>
>Thanks
>
>On Sun, Jan 25, 2015 at 10:30 PM, Felix Schumacher <
>felix.schumacher@internetallee.de> wrote:
>
>>
>>
>> Am 25. Januar 2015 21:35:48 MEZ, schrieb pmouawad@apache.org:
>> >Author: pmouawad
>> >Date: Sun Jan 25 20:35:48 2015
>> >New Revision: 1654701
>> >
>> >URL: http://svn.apache.org/r1654701
>> >Log:
>> >Remove unused fields
>> >
>> >Modified:
>> >
>jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java
>> >
>> >Modified:
>> >jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java
>> >URL:
>> >
>>
>http://svn.apache.org/viewvc/jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java?rev=1654701&r1=1654700&r2=1654701&view=diff
>>
>>
>>==============================================================================
>> >---
>jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java
>> >(original)
>> >+++
>jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java
>> >Sun Jan 25 20:35:48 2015
>> >@@ -54,11 +54,6 @@ public class ThreadLocalRandom extends R
>> > */
>> > boolean initialized;
>> >
>> >- // Padding to help avoid memory contention among seed updates
>in
>> >- // different TLRs in the common case that they are located near
>> >- // each other.
>> >- private long pad0, pad1, pad2, pad3, pad4, pad5, pad6, pad7;
>>
>> Given the comment above the fields, I would not remove those padding
>> fields.
>>
>> Regards
>> Felix
>> >-
>> > /**
>> > * The actual ThreadLocal
>> > */
>>
>>
Re: svn commit: r1654701 - /jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java
Posted by Philippe Mouawad <ph...@gmail.com>.
Hi Felix,
Reverted , can you explain to me this ? I don't see these fields used, are
they through reflection ?
Thanks
On Sun, Jan 25, 2015 at 10:30 PM, Felix Schumacher <
felix.schumacher@internetallee.de> wrote:
>
>
> Am 25. Januar 2015 21:35:48 MEZ, schrieb pmouawad@apache.org:
> >Author: pmouawad
> >Date: Sun Jan 25 20:35:48 2015
> >New Revision: 1654701
> >
> >URL: http://svn.apache.org/r1654701
> >Log:
> >Remove unused fields
> >
> >Modified:
> > jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java
> >
> >Modified:
> >jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java
> >URL:
> >
> http://svn.apache.org/viewvc/jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java?rev=1654701&r1=1654700&r2=1654701&view=diff
>
> >==============================================================================
> >--- jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java
> >(original)
> >+++ jmeter/trunk/src/core/org/apache/jmeter/util/ThreadLocalRandom.java
> >Sun Jan 25 20:35:48 2015
> >@@ -54,11 +54,6 @@ public class ThreadLocalRandom extends R
> > */
> > boolean initialized;
> >
> >- // Padding to help avoid memory contention among seed updates in
> >- // different TLRs in the common case that they are located near
> >- // each other.
> >- private long pad0, pad1, pad2, pad3, pad4, pad5, pad6, pad7;
>
> Given the comment above the fields, I would not remove those padding
> fields.
>
> Regards
> Felix
> >-
> > /**
> > * The actual ThreadLocal
> > */
>
>
--
Cordialement.
Philippe Mouawad.