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

[Coleen Phillimore]

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().

+        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
>