[hibernate-dev] Optimizing reflection optimization
Steve Ebersole
steve at hibernate.org
Wed Jun 2 14:01:29 EDT 2010
Ok, now that is reasonable :) And looking through the source (for Field
at least) is does circumvent a lot of checks if accessible is set.
So I can move the '!ReflectHelper.isPublic' check into the catch blocks
to continue to error in cases where we *need* to call setAccessible; for
other cases I'd just warn:
if ( !ReflectHelper.isPublic(theClass, method) ) {
method.setAccessible(true);
}
becomes:
if ( !method.isAccessible() ) {
try {
method.setAccessible( true );
}
catch ( SecurityException se ) {
if ( !ReflectHelper.isPublic( theClass, method ) ) {
throw se;
}
else {
log.warn( ... );
}
}
}
Could you please create a JIRA?
On Wed, 2010-06-02 at 17:44 +0300, Кирилл Кленский wrote:
> "We do in fact utilize setAccessible in the Hibernate code"
>
>
> Yes, but if I am not mistaken only if the method/field is not public.
> From code: !ReflectHelper.isPublic(theClass, method) )
> method.setAccessible(true);
> We could increase performance easily if we call setAccessible even for
> public methods - we get rid of costly security checks.
>
>
> Kirill
>
>
> 2 июня 2010 г. 16:57 пользователь Steve Ebersole <steve at hibernate.org>
> написал:
> Perhaps. We do in fact utilize setAccessible in the Hibernate
> code and
> so when I did performance testing I did that as well as it
> most closely
> matched our actual usage. Most likely it applies the checks
> "up front"
> when setAccessible is called.
>
> I'll take a look at the test and the numbers when i have a
> chance
> (probably not till next week), but it is difficult to mimic
> all the
> variables that come into play in different server environments
> (using
> server versus client is only a small part).
>
>
> On Wed, 2010-06-02 at 13:24 +0300, Кирилл Кленский wrote:
> > Hi,
> >
> >
> > I have done some tests that are more pure in that they do
> not involve
> > the application logic.
> >
> >
> > Java version: jdk1.6.0_19 32-bit
> > Results include both client and server mode tests. Numbers
> represent
> > 100 000 000 invocations time in milliseconds.
> >
> >
> > The result format is the following:
> > server_mode_test_time(server_mode_warmup_time) -
> > client_mode_test_time(client_mode_warmup_time)
> >
> >
> > ==========================
> > Method access with direct call
> > 24(4) - 69(70)
> >
> >
> > Method access with reflection
> > 815(3893) - 36 969(39162)
> >
> >
> > Method access with reflection and setAccessible(true)
> > 339(640) - 1297(1356)
> >
> >
> > Method access with generated bytecode
> > 3(2) - 646(666)
> >
> >
> > Field access with reflection
> > 40333(40016) - 40333(58800)
> >
> >
> > Field access with reflection and setAccessible(true)
> > 729(786) - 729(7696)
> > ==========================
> >
> >
> > I have the following thoughts after all:
> >
> >
> > 1. Generated bytecode is comparable to direct access.
> Strange enough
> > that it was even faster than direct access in server mode.
> Tests show
> > that JVM seems to optimize reflection calls (warmup helps)
> but the
> > difference between reflection and direct calls is huge.
> > 2. Setting Method.setAccessible() and Field.setAccessible()
> to true
> > helps to avoid security checks and increases the
> performance. May be
> > this is the trick Bill is talking about?
> > This potentially could be a relatively easy way to increase
> the
> > performance especially if JVM is running in client mode
> (method
> > invocation security checks take approx 10 times more time in
> client
> > mode compared to server). In server mode the increase is
> relatively
> > small for methods (several times) and huge for fields
> (approx 50
> > times).
> >
> >
> > I have attached the test code if somebody wants to compare
> results.
> > Javassist 3.8.0.GA was used to generate bytecode and is
> required to
> > build/run the test.
> >
> >
> > Regards,
> > Kirill Klenski
> >
> >
> > 2010/5/27 Steve Ebersole <steve at hibernate.org>
> > Perhaps it short circuits those copies and other
> overheads if
> > no
> > security manager is defined (ala as in my IDE).
> That would
> > explain how
> > I can see minimal improvement while Kirill sees a 4x
> > improvement.
> >
> > Still rather confirm these numbers are accurate.
> Kirill?
> >
> >
> > On Thu, 2010-05-27 at 10:12 -0400, Bill Burke wrote:
> > > Carlo deWolfe found that one of the big perf
> problems with
> > Java
> > > reflection is that it is constantly doing security
> checks
> > with the
> > > security manager and every get/find request makes
> a copy of
> > the
> > > method/field objects. He had a hack for this, but
> you'll
> > have to
> > > consult him on what it is. The JBoss Reflections
> project
> > might have it.
> > >
> > > I think once this hack is intiated, it is an
> improvement
> > over Javassist.
> > > If you think about it, Java VM has to build up
> this
> > information anyways...
> > >
> > > Steve Ebersole wrote:
> > > > I ran this same exact comparison before and I
> seem to
> > recall much
> > > > different results. Unfortunately I no longer
> have that
> > code. This was
> > > > part of
> > > >
> >
> http://opensource.atlassian.com/projects/hibernate/browse/HHH-227
> > > >
> > > > Can you make sure you "prime" or "warm up" the
> jvm before
> > you start
> > > > taking measurements?
> > > >
> > > > On Thu, 2010-05-27 at 15:39 +0300, Кирилл
> Кленский wrote:
> > > >> Hi,
> > > >>
> > > >> My measurements have indicated that there is a
> > performance gain. I have
> > > >> measured the time spent in setPropertyValues
> and
> > getPropertyValues.
> > > >> The optimized version was 4 times faster in
> these methods
> > giving an
> > > >> estimated application performance increase of
> about 3%.
> > > >> Optimizing getPropertyValue and
> setPropertyValue could
> > give 1.5% more
> > > >> according to our rough calculations.
> > > >>
> > > >> Kirill
> > > >>
> > > >> 26 мая 2010 г. 23:53 пользователь Emmanuel
> Bernard
> > > >> <emmanuel at hibernate.org>написал:
> > > >>
> > > >>> Hi,
> > > >>> Have you noticed a perf difference in your
> application
> > with and without the
> > > >>> patch?
> > > >>> I am wondering if modern VMs have catched up
> with what
> > Javassist does.
> > > >>>
> > > >>> On 26 mai 2010, at 18:29, Кирилл Кленский
> wrote:
> > > >>>
> > > >>>> 1. I have noticed that
> > > >>>>
> >
> org.hibernate.bytecode.javassist.BulkAccessorFactory.findAccessors(...)
> > > >>> is
> > > >>>> searching for accessor methods in the
> optimized entity
> > class only. This
> > > >>>> means that the methods from the superclasses
> are not
> > visible during
> > > >>>> BulkAccessor creation unless overridden by
> child
> > classes. By enhancing
> > > >>> the
> > > >>>> algorithm to search down the inheritance tree
> we could
> > avoid creation of
> > > >>>> redundant methods which increase the code
> verbosity a
> > lot. In our case
> > > >>>> almost all the entities are inherited from
> the base
> > classes having the
> > > >>>> common entity properties defined, so the
> reflection
> > optimization does not
> > > >>>> work for any of them until we override the
> inherited
> > methods in all the
> > > >>>> child classes. The implementation is trivial,
> but I
> > have got a ready
> > > >>>> prototype if anybody is interested.
> > > >>>
> > > >> _______________________________________________
> > > >> hibernate-dev mailing list
> > > >> hibernate-dev at lists.jboss.org
> > > >>
> https://lists.jboss.org/mailman/listinfo/hibernate-dev
> > > >
> > > >
> > >
> >
> >
> > --
> >
> >
> > Steve Ebersole <steve at hibernate.org>
> > http://hibernate.org
> >
> >
> >
> >
>
>
>
> --
>
> Steve Ebersole <steve at hibernate.org>
> http://hibernate.org
>
>
>
--
Steve Ebersole <steve at hibernate.org>
http://hibernate.org
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