Merging the MacOS X Port into HotSpot Express 23 (7098194)

[Daniel D. Daugherty]

On 10/12/11 7:59 PM, David Holmes wrote:
> Okay, I won't respond to all the past emails concerning my first round 
> comments, but will start afresh here utilising the additional 
> information that has been provided.

Thanks. I appreciate that since this review has taken more time
than anyone predicted.


> But first a new comment:
>
> src/os_cpu/bsd_zero/vm/os_bsd_zero.cpp (and probably elsewhere)
>
>  fatal(err_msg("pthread_attr_init failed with err = " INT32_FORMAT, 
> rslt));
>
> It is far more informative to provide the error string 
> "strerror(rslt)" than the decimal value of the error code. (We're 
> probably guilty of this in many places but lets not propagate bad 
> habits.)

Changing the format string from "%d" to INT32_FORMAT was done
because Paul pointed out that HotSpot isn't supposed to use
format specifiers like "%d" directly.

That is different than changing the output from a decimal to
string which I think is beyond the scope of this changeset. It
does raise interesting questions about error diagnostics and,
if memory serves me correctly, there is an open bug for improving
error diagnostics...

And, yes, I'll have to check the equivalent Linux code to see if
the format strings need to be fixed there also. I suspect they do,
but I already have plans (and a script) to make a pass at sync'ing
BSD improvements back to Linux.


>   src/share/vm/prims/jni.cpp + thread.*
>
> !   thread->set_done_attaching_via_jni();
>
> I think the naming has gotten overly verbose here. The only way to 
> attach is by definition via JNI. I don't think there was anything 
> wrong with the existing _is_attaching logic (yes I added it! ;-) ) and 
> my only complaint was that the new _is_attached should really be 
> _was_attached. Perhaps a better/simpler/cleaer approach here would 
> have been to have a field: can_set_native_thread_name, and only set it 
> to true in the non-attaching case. Another cleanup RFE perhaps.

On several occasions I have fielded questions about the difference
between "attach on demand" and "JNI attach" so there is definitely
confusion out there. I think the renaming adds clarity and I had
thought you would like the reduction in number of fields. I also
think the new JNIAttachStates is cleaner and more clear. I think
that adding a field called can_set_native_thread_name is going to
cause some confusion with JVM/TI capabilities since all of those
are named in the style of can_do_this and can_do_that.


> src/share/vm/utilities/debug.cpp
>
> Normally if we propose to move something into a product build there is 
> a discussion about what we are moving, why, and what the impact is on 
> build size and runtime performance. I don't see any of that here. :(

I've only recently joined the MacOS Port project so I have no idea
what was discussed before I arrived. I have difficulty imagining
that the changes to debug.cpp will add much to the size and I don't
think they will affect runtime performance unless they are used.
Compared to what I just added via Full Debug Symbols, this has got
to be a drop in the bucket :-)


> - set_native_thread_name:
>
> Ok so I have to go back to earlier emails here. Makes sense that 
> Thread.setName is augmented to call JVM_SetNativeThreadName. However I 
> don't like the semantics of this particular addition. setName has no 
> usage restrictions on it, but set_native_thread_name is a no-op unless 
> called by the current thread. By restricting it to the current thread 
> it simplifies synchronization logic, but it seems a somewhat arbitrary 
> restriction in terms of the functionality, given the more general 
> nature of the setName API. I guess this is Yet Another RFE: 
> set_native_thread_name should not be restricted to only the current 
> thread.

We definitely need to get some clarity about the addition of
JVM_SetNativeThreadName(). I'm not fond of APIs without return
values so that's one thing to log in the new bug. The "must be
current thread" semantic should also be hashed out/clarified.

Like any API between the JDK and HotSpot, changing it will be a
pain and require coordination.

> BTW: are the JDK changes associated with this also being pushed at 
> some stage?

Yes, but the exact process has not been finalized. Since there
are changes being made/coordinated by multiple teams, I'm not
sure which JDK8 sub-repos will be used.


> If so are the hotspot changes being pushed first?

I'm planning to push this changeset to RT_Baseline today. I don't
know if there is an HSX-B23-B02 snapshot this week, but I think
I've missed the window by one day. Normally changes have to hit
RT_Baseline by Wednesday nightly cut-off to be included in the
RT_Baseline -> Main_Baseline push for a given week...

However, I don't know your plans for gatekeeping this week so
maybe you aren't planning to push until Friday morning.

Strangely enough, because I'm pushing to HSX-23 via RT_Baseline,
my repo coordination life is much easier. HSX-23 will get to
JDK7u via a bulk update so I don't have to juggle too much...

Dan




>
> Cheers,
> David
>
> On 13/10/2011 10:56 AM, Daniel D. Daugherty wrote:
>> Greetings,
>>
>> I've closed out Code Review Round 0 and I'm posting new webrevs
>> for Code Review Round 1:
>>
>> Here's the webrev for just the deltas between Code Review Round 0
>> and Code Review Round 1:
>>
>> http://cr.openjdk.java.net/~dcubed/mac_os_x_port/7098194-webrev/1-deltas-only 
>>
>>
>>
>> Here's the webrev for all the changes in one shot:
>>
>> http://cr.openjdk.java.net/~dcubed/mac_os_x_port/7098194-webrev/1-all/
>>
>> And here are the same subset webrevs:
>>
>> http://cr.openjdk.java.net/~dcubed/mac_os_x_port/7098194-webrev/1-bsd-resync/ 
>>
>>
>> http://cr.openjdk.java.net/~dcubed/mac_os_x_port/7098194-webrev/1-macosx-other-code/ 
>>
>>
>> http://cr.openjdk.java.net/~dcubed/mac_os_x_port/7098194-webrev/1-macosx-dtrace-code/ 
>>
>>
>> http://cr.openjdk.java.net/~dcubed/mac_os_x_port/7098194-webrev/1-macosx-infra/ 
>>
>>
>>
>>
>> Here's my current commit message:
>>
>>> 7098194: integrate macosx-port changes
>>> Summary: Integrate macosx-port/hotspot changes as of 2011.09.29.
>>> Reviewed-by: kvn, dholmes, never, phh
>>> Contributed-by: Christos Zoulas <christos at zoulas.com>, Greg Lewis
>>> <glewis at eyesbeyond.com>, Kurt Miller <kurt at intricatesoftware.com>,
>>> Alexander Strange <astrange at apple.com>, Mike Swingler
>>> <swingler at apple.com>, Roger Hoover <rhoover at apple.com>
>>
>> Thanks, in advance, for any final feedback for this changeset.
>>
>> Dan
>>
>>
>>> Greetings,
>>>
>>> Tom R shepherded the the BSD Port into HotSpot Express 23 using:
>>>
>>> 7089790 integrate bsd-port changes
>>>
>>> and I'm following up on that work using the following bug:
>>>
>>> 7098194 integrate macosx-port changes
>>>
>>> The synopsis is a bit off. In reality, the 7098194changeset will
>>> include additional changes from the BSD Port in addition the deltas
>>> made by the MacOS X Port. The bsd-port/hotspot tip changeset for
>>> this resync is:
>>>
>>> changeset: 2729:f1a18ada5853
>>> tag: tip
>>> user: Greg Lewis <glewis at eyesbeyond.com>
>>> date: Wed Sep 21 22:29:10 2011 -0700
>>> summary: . Finish removing hsearch_r.
>>>
>>> The macosx-port/hotspot changeset for this merge is:
>>>
>>> changeset: 2756:69de8d34a370
>>> tag: tip
>>> user: swingler at apple.com
>>> date: Thu Sep 29 18:10:16 2011 -0700
>>> summary: Adding JAVA_LIBRARY_PATH for bundled app launching
>>> (avoids stomping DYLD_LIBRARY_PATH)
>>>
>>> The focus of 7098194 is to get the MacOS X port into HSX-23 without
>>> regressing the non-MacOS X platforms. In other words, we're trying
>>> to get HSX-23 caught up with the BSD Port and MacOS X Port projects.
>>> Shaking out the MacOS X Port itself will be done with other changesets
>>> on an as needed basis.
>>>
>>> Just to be clear, the push target for this changeset is the RT_Baseline
>>> sub-repo of HotSpot Express (currently HSX-23):
>>>
>>> http://hg.openjdk.java.net/hsx/hotspot-rt/hotspot
>>>
>>> Like what Tom did for 7089790, I'm posting multiple webrevs so folks
>>> can review these changes in different ways. My primary focus here is
>>> the common or shared code so I'm less worried about the BSD or MacOS X
>>> specific changes. Obviously, if you see something I messed up in those
>>> files, I'd like to know.
>>>
>>> Here's the webrev for all the changes in one shot:
>>>
>>> http://cr.openjdk.java.net/~dcubed/mac_os_x_port/7098194-webrev/0-all/
>>>
>>> The order of the files in the above webrev is the same as for
>>> for the subset webrevs below.
>>>
>>> Here's the webrevs for the changes in subsets:
>>>
>>> http://cr.openjdk.java.net/~dcubed/mac_os_x_port/7098194-webrev/0-bsd-resync/ 
>>>
>>>
>>>
>>> The above webrev has the changes to the bsd-port/hotspot repo made
>>> after Tom R's work on 7089790 (the 2011.08.02 wiki snapshot).
>>>
>>> http://cr.openjdk.java.net/~dcubed/mac_os_x_port/7098194-webrev/0-macosx-other-code/ 
>>>
>>>
>>>
>>> The above webrev has the non-Dtrace and non-infrastructure changes
>>> made for the MacOS X port. There's a couple of files that also contain
>>> Dtrace related changes, but I decided it was better to include those
>>> files in this subset.
>>>
>>> http://cr.openjdk.java.net/~dcubed/mac_os_x_port/7098194-webrev/0-macosx-dtrace-code/ 
>>>
>>>
>>>
>>> The above webrev has almost all of the changes to enable Dtrace on
>>> MacOS X (a couple of files are in the macosx-other-code subset).
>>> On MacOS X, a newer version of Dtrace is implemented than on Solaris
>>> which is why the code is #ifdef'ed. I had to change the original
>>> #ifdef'ing because the original implementation had put some non-Dtrace
>>> code into #ifdef USDT1 ... #endif blocks so the code didn't build on
>>> non-Solaris platforms. In order to be more clean with #ifdef'ing, I
>>> redid all MacOS X Dtrace #ifdef'ing in the following forms:
>>>
>>> #ifndef USDT2
>>> <older Dtrace implementation is in this block>
>>> <some non-Dtrace code (macros) that call the older Dtrace>
>>> <implementation are also in this block>
>>> #else /* USDT2 */
>>> <new Dtrace implementation for MacOS X in this block>
>>> #endif /* USDT2 */
>>>
>>> #ifndef USDT2
>>> <older Dtrace implementation is in this block>
>>> <no #else because the newer Dtrace doesn't need/have the equivalent>
>>> #endif /* ! USDT2 */
>>>
>>> Yes, I realize that the MacOS X Dtrace implementation does not follow
>>> HotSpot style guidelines very consistently, but I decided not to fix
>>> that so I could diff against the macosx-port/hotspot more reliably.
>>>
>>> I have to consult with Keith McGuigan about how to migrate the Solaris
>>> Dtrace implementation to the newer version. However, that work will be
>>> done independently of this bug (7098194).
>>>
>>> http://cr.openjdk.java.net/~dcubed/mac_os_x_port/7098194-webrev/0-macosx-infra/ 
>>>
>>>
>>>
>>> The above webrev has all the infrastructure (e.g., Makefile) related
>>> changes. Many/most folks aren't interested in Makefile stuff so I've
>>> put these changes in their own subset. Of course, I need Kelly O'Hair
>>> to bless these changes...
>>>
>>> Builds done so far:
>>>
>>> - Solaris X86 builds of {Client, Server} VM * {product, fastdebug, 
>>> jvmg}
>>> - WinXP builds of {Client, Server} VM * {product, fastdebug, debug}
>>> - MacOS 10.6.8/Xcode 3.2.6 build of the macosx-port forest with new
>>> HSX repo
>>> - MacOS 10.7/Xcode 4.1.1 build of the macosx-port forest with new HSX
>>> repo
>>>
>>> Testing done so far:
>>>
>>> - Serviceability stack (25 subsuites):
>>> VM/NSK: jvmti, jvmti_unit, jdwp, jdi, sa-jdi, heapdump, hprof, jdb,
>>> logging, mm
>>> SDK/JDK: jdi, jdi_closed, jli, logging, mm_csjmx, mm_csm, mm_jlm,
>>> mm_jlm_closed, mm_jmx, mm_jmx_closed, mm_sm, mm_sm_closed,
>>> misc_attach, misc_jvmstat, misc_tools
>>> - Tested configs (8 configs)
>>> {Solaris X86, WinXP} * {Client, Server} VM * {-Xmixed, -Xcomp}
>>>
>>> - MacOS X builds have only had minimal 'java -version' type testing,
>>> i.e., did the build "work"?
>>>
>>> No regressions have been seen in the Solaris X86 testing and WinXP
>>> testing should be finished later today.
>>>
>>> Things still to do (in no particular order):
>>>
>>> - gather the list of contributors for the changeset comment
>>> - JPRT test jobs when the JPRT-hotspotwest queue settles down
>>> - dtrace testing on Solaris X86
>>> - code review
>>> - start bring up of more formal dev testing on MacOS X
>>>
>>> Thanks, in advance, for any review comments.
>>>
>>> Dan
>>>
>>>