[11] RFR(S): 8206998: [test] runtime/ElfDecoder/TestElfDirectRead.java requires longer timeout on ppc64

David Holmes david.holmes at oracle.com
Wed Jul 11 07:41:54 UTC 2018

Hi Volker,

On 11/07/2018 5:34 PM, Volker Simonis wrote:
> Hi David,
> so it obviously works and as Goetz mentioned there are already other,
> existing tests which use this feature.
> Do you want me to get a formal review which confirms this from
> somebody from the JTreg team?
> I've CC-ed jtreg-use and Jonathan in the hope that they can confirm this.

No that's fine - just surprised to see this (and couldn't find any 
documentation for it!).


> Regards,
> Volker
> On Tue, Jul 10, 2018 at 11:24 PM, David Holmes <david.holmes at oracle.com> wrote:
>> Hi Volker,
>> On 11/07/2018 3:52 AM, Volker Simonis wrote:
>>> Hi,
>>> can I please get a review for the following test-only change:
>>> http://cr.openjdk.java.net/~simonis/webrevs/2018/8206998/
>>> https://bugs.openjdk.java.net/browse/JDK-8206998
>>> The problem is that the test runtime/ElfDecoder/TestElfDirectRead.java
>>> intentionally disables caching of Elf sections during symbol lookup
>>> with WhiteBox.disableElfSectionCache(). On platforms which do not use
>>> file descriptors instead of plain function pointers this slows down
>>> the lookup just a little bit, because all the symbols from an Elf file
>>> are still read consecutively after one 'fseek()' call. But on
>>> platforms with file descriptors like ppc64 big-endian, we get two
>>> 'fseek()' calls for each symbol read from the Elf file because reading
>>> the file descriptor table is nested inside the loop which reads the
>>> symbols. This really trashes the I/O system and considerable slows
>>> down the test, so we need an extra long timeout setting.
>>> The fix is trivial - simply provide two test versions (i.e. comments):
>>> the first one for all Linux flavors which are not ppc64 and a second,
>>> new one for Linux/ppc64 which simply has a bigger timeout.
>> I was not aware that this was a valid way of defining a test! This suggests
>> there can only be one "leading comment" per "defining file:
>> http://openjdk.java.net/jtreg/tag-spec.html
>> Need to verify this with the jtreg folk: jtreg-use at openjdk.java.net
>> Thanks,
>> David
>>> Thank you and best regards,
>>> Volker

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