RFR(M): JDK-8163011: AArch64: NMT detail stack trace cleanup

Dmitry Samersov dmitry.samersoff at bell-sw.com
Tue Sep 5 09:25:58 UTC 2017


> Am I missing something obvious to account for the lack of symbols in
> my trace output?

It looks like your libjvm.so get stripped for some reason.

I don't have jdk8 build setup but:

I'd checked

1. Official jdk8/x86_64 downloaded from oracle site

2. jdk10/x86_64 built with --with-debug-level=release

3. jdk10/aarch64 built with --with-debug-level=release

In all three cases .symtab is present and output of

${TESTJAVA}/bin/java -XX:NativeMemoryTracking=detail
-XX:+UnlockDiagnosticVMOptions -XX:+PrintNMTStatistics -version

contains symbols (e.g):

[0x0000ffffae39ebf8] ReservedSpace::ReservedSpace(unsigned long,
unsigned long)+0x94
[0x0000ffffadf4dd5c] CodeHeap::reserve(ReservedSpace, unsigned long,
unsigned long)+0x194
[0x0000ffffaddb2de4] CodeCache::add_heap(ReservedSpace, char const*,
[0x0000ffffaddb3140] CodeCache::initialize_heaps()+0x2fc
                             (reserved=48KB, committed=20KB)


On 04.09.2017 17:28, Andrew Dinn wrote:
> On 04/09/17 14:49, dmitry.samersov wrote:
>>> Yes, but NMT also works (and is meant to work) on product builds where
>>> the required symbols are not available.
>> 1. This patch doesn't affect product build. On product build we have all
>> NMT frames inlined and don't need to skip anything.
>> I'll put these changes under #ifndef PRODUCT to make it clear visible.
> Ok, thank you for correcting my misunderstanding here.
>> 2. NMT uses .symtab section and these symbols also available in release
>> build by default, unless someone manually strip libjvm.so
> Hmm, apologies once again if I have misunderstood how things work in
> release builds. I have been using NMT in the last 2 weeks, albeit under
> jdk8, and symbols were *not* displayed when running my local product
> build (the traces simply displayed hex addresses). I configured the
> build with
>   --with-debug-level=release --disable-zip-debug-info
> Am I missing something obvious to account for the lack of symbols in my
> trace output?
> regards,
> Andrew Dinn
> -----------
> Senior Principal Software Engineer
> Red Hat UK Ltd
> Registered in England and Wales under Company Registration No. 03798903
> Directors: Michael Cunningham, Michael ("Mike") O'Neill, Eric Shander

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