About C2 changes.
.ad files. I am thinking may be we should put new code in separate <arch>_shenandoah.ad files and merge them only if
Shenandoah is included in built [1]. I don't like #ifdefs - you still generate this mach nodes even without Shenandoah.
debug_final_field_at() and debug_stable_field_at() are not used - could be
excluded from changes.
loopnode.cpp Sometimes you add #if INCLUDE_SHENANDOAHGC and sometimes don't. Be consistent. I don't know why you need
#ifdef if such nodes should be generated without Shenandoah
compile.cpp - no need to include shenandoahBarrierSetC2.hpp
type.hpp - cast_to_nonconst() are not used.
phasetype.hpp, subnode.cpp - don't add files with only cleanup changes.
I wish loopnode.cpp and loopopts.cpp changes were more clean.
I like the idea where you expose only one ShenandoahBarrier node to C2 and hide all subnodes behind it. I really don't
want to see a lot of Shenandoah*Node new classes in C2 shared code.
Thanks,
Vladimir
[1]
http://hg.openjdk.java.net/jdk/jdk/file/157c1130b46e/make/hotspot/gensrc/GensrcAdlc.gmk#l122
On 11/28/18 2:29 PM, Roman Kennke wrote:
Alright, we fixed:
- The minor issues that Kim reported in shared-gc
- A lot of fixes in shared-tests according to Leonid's review
- Disabled SA heapdumping similar to ZGC as Per suggested
Some notes:
Leonid: test/hotspot/jtreg/gc/TestFullGCCount.java was actually
correct. The @requires there means to exclude runs with both CMS and
ExplicitGCInvokesConcurrent at the same time, because that would be
(expectedly) failing. It can run CMS, default GC and any other GC just
fine. Adding the same clause for Shenandoah means the same, and filters
the combination (+UseShenandoahGC)+(+ExplicitGCInvokesConcurrent). I
made the condition a bit clearer by avoiding triple-negation.
See:
http://mail.openjdk.java.net/pipermail/shenandoah-dev/2018-November/008457.html
Per: Disabling the SA part for heapdumping makes 2 tests fail:
- test/hotspot/jtreg/serviceability/sa/ClhsdbJhisto.java
- test/hotspot/jtreg/serviceability/sa/TestHeapDumpForLargeArray.java
we filter them for Shenandoah now. I'm wondering: how do you get past
those with ZGC?
See:
http://mail.openjdk.java.net/pipermail/shenandoah-dev/2018-November/008466.html
(Note to Leonid and tests reviewers: I'll add those related filters in
next round).
Vladimir: Roland integrated a bunch of changes to make loop* code look
better. I can tell that we're not done with C2 yet. Can you look over
the code and see what is ok, and especially what is not ok, so that we
can focus our efforts on the relevant parts?
Updated set of webrevs:
http://cr.openjdk.java.net/~rkennke/shenandoah-upstream/01/
Thanks,
Roman
Hi,
This is the first round of changes for including Shenandoah GC into
mainline.
I divided the review into parts that roughly correspond to the mailing lists
that would normally review it, and I divided it into 'shared' code
changes and
'shenandoah' code changes (actually, mostly additions). The intend is to
eventually
push them as single 'combined' changeset, once reviewed.
JEP:
https://openjdk.java.net/jeps/189
Bug entry:
https://bugs.openjdk.java.net/browse/JDK-8214259
Webrevs:
http://cr.openjdk.java.net/~rkennke/shenandoah-upstream/00/
For those who want to see the full change, have a look at the
shenandoah-complete
<http://cr.openjdk.java.net/~rkennke/shenandoah-upstream/00/shenandoah-complete/>
directory,
it contains the full combined webrev. Alternatively, there is the file
shenandoah-master.patch
<http://cr.openjdk.java.net/~rkennke/shenandoah-upstream/00/shenandoah-master.patch>,
which is what I intend to commit (and which should be equivalent to the
'shenandoah-complete' webrev).
Sections to review (at this point) are the following:
*) shenandoah-gc
<http://cr.openjdk.java.net/~rkennke/shenandoah-upstream/00/shenandoah-gc/>
- Actual Shenandoah implementation, almost completely residing in
gc/shenandoah
*) shared-gc
<http://cr.openjdk.java.net/~rkennke/shenandoah-upstream/00/shared-gc/>
- This is mostly boilerplate that is common to any GC
- referenceProcessor.cpp has a little change to make one assert not
fail (next to CMS and G1)
- taskqueue.hpp has some small adjustments to enable subclassing
*) shared-serviceability
<http://cr.openjdk.java.net/~rkennke/shenandoah-upstream/00/shared-serviceability/>
- The usual code to support another GC
*) shared-runtime
<http://cr.openjdk.java.net/~rkennke/shenandoah-upstream/00/shared-runtime/>
- A number of friends declarations to allow Shenandoah iterators to
hook up with,
e.g. ClassLoaderData, CodeCache, etc
- Warning and disabling JFR LeakProfiler
- fieldDescriptor.hpp added is_stable() accessor, for use in
Shenandoah C2 optimizations
- Locks initialization in mutexLocker.cpp as usual
- VM operations defines for Shenandoah's VM ops
- globalDefinitions.hpp added UINT64_FORMAT_HEX_W for use in
Shenandoah's logging
- The usual macros in macro.hpp
*) shared-build
<http://cr.openjdk.java.net/~rkennke/shenandoah-upstream/00/shared-build/>
- Add shenandoah feature, enabled by default, as agreed with
Vladimir K. beforehand
- Some flags for shenandoah-enabled compilation to get
SUPPORT_BARRIER_ON_PRIMITIVES
and SUPPORT_NOT_TO_SPACE_INVARIANT which is required for
Shenandoah's barriers
- --param inline-unit-growth=1000 settings for 2 shenandoah source
files, which is
useful to get the whole marking loop inlined (observed significant
regression if we
don't)
*) shared-tests
<http://cr.openjdk.java.net/~rkennke/shenandoah-upstream/00/shared-tests/>
- Test infrastructure to support Shenandoah
- Shenandoah test groups
- Exclude Shenandoah in various tests that can be run with selected GC
- Enable/add configure for Shenandoah for tests that make sense to
run with it
*) shenandoah-tests
<http://cr.openjdk.java.net/~rkennke/shenandoah-upstream/00/shenandoah-tests/>
- Shenandoah specific tests, most reside in gc/shenandoah subdirectory
- A couple of tests configurations have been added, e.g.
TestGCBasherWithShenandoah.java
I intentionally left out shared-compiler for now, because we have some
work left to do
there, but if you click around you'll find the patch anyway, in case you
want to take
a peek at it.
We have regular builds on:
- {Linux} x {x86_64, x86_32, armhf, aarch64, ppc64el, s390x}
- {Windows} x {x86_64},
- {MacOS X} x {x86_64}
This also routinely passes:
- the new Shenandoah tests
- jcstress with/without aggressive Shenandoah verification
- specjvm2008 with/without aggressive Shenandoah verification
I'd like to thank my collegues at Red Hat: Christine Flood, she deserves
the credit for being the original inventor of Shenandoah, Aleksey
Shiplëv, Roland Westrelin & Zhengyu Gu for their countless
contributions, everybody else in Red Hat's OpenJDK team for testing,
advice and support, my collegues in Oracle's GC, runtime and compiler
teams for tirelessly helping with and reviewing all the GC interface and
related changes, and of course the many early adopters for reporting
bugs and success stories and feature requests: we wouldn't be here
without any of you!
Best regards,
Roman
