RFR(s): 8149036: Add UL tracing for thread related events at os level

[David Holmes]

Hi Coleen,

On 23/02/2016 8:45 AM, Coleen Phillimore wrote:
> On 2/22/16 3:53 PM, Coleen Phillimore wrote:
>>
>> Hi Thomas,
>> I think the logging conversion looks really good.  The errno stuff is
>> very ugly though.  Can you call strerrno_r - the thread safe version?
>> I didn't see discussion around this.
>
> Hi Thomas, I was talking to Kim.  You should use strerror() and not add
> this code to os.cpp. The rationale is in this bug:
>
> https://bugs.openjdk.java.net/browse/JDK-6223913
>
> It seems like the errors would have standard errno at this point and
> wouldn't be susceptible to the race in strerror().

We re-filed

https://bugs.openjdk.java.net/browse/JDK-8148425

to cover the strerror issue. As noted there the problem can also arise 
if localization of the error strings is applied.

David
-----

> +        log.warning("Failed to start thread - pthread_create failed
> (%s) for attributes: %s.",
> +          os::errno_name(errno), os::Posix::describe_pthread_attr(buf,
> sizeof(buf), &attr));
>
> It seems the chance of a race creating different errno at this early
> point in the jvm is very low.
>
> Coleen
>
>> Thanks,
>> Coleen
>>
>> On 2/22/16 11:54 AM, Thomas Stüfe wrote:
>>> Dear all,
>>>
>>> please take a look at this proposed addition to UL. This adds a
>>> number of
>>> trace points to thread creation. In detail:
>>>
>>> - it traces thread creation and thread creation errors, including
>>> pthread
>>> attributes (for Posix platforms)
>>> - it traces stack location and creation/removal of stack guard pages.
>>>
>>> This all was first AIX-only tracing, but I converted this to UL and
>>> made it
>>> available on all platforms.
>>>
>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8149036
>>> Webrev:
>>> http://cr.openjdk.java.net/~stuefe/webrevs/8149036-add-tracing-for-thread-events/webrev.00/webrev/
>>>
>>>
>>> Note also that I added a helper function, os::errno_name(), which is
>>> a very
>>> simple replacement for strerror() without its problems (thread safety,
>>> unwanted localizations...).
>>>
>>> What do you think?
>>>
>>> Kind Regards, Thomas
>>
>