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

[Thomas Stüfe]

On Wed, Feb 24, 2016 at 1:30 PM, Coleen Phillimore <
coleen.phillimore at oracle.com> wrote:

>
>
> On 2/24/16 4:24 AM, Thomas Stüfe wrote:
>
> Coleen, Marcus,
>
> thank you for reviewing, and @Coleen, thanks for the sponsoring offer!
>
> Here the latest Webrev:
> http://cr.openjdk.java.net/~stuefe/webrevs/8149036-add-tracing-for-thread-events/webrev.02/webrev/index.html
>
> As Marcus suggested, I added a new "thread" tag and added the tag to the
> logging calls.
>
> btw, I found the command line a bit confusing:
>
>
> I find it completely baffling myself.   The documentation for this feature
> needs a lot of work.  In runtime, we've steered away from this multiple tag
> combinations because as you say below, many of the logging we want should
> be specified as -Xlog:A* if we added more tags, and it's not intuitive to
> me to add "*" to my command line arguments in bash.
>
> Coleen
>
>
I am glad to see that I am not alone. As I was writing in the answer to
David, I really like the multiple-tags-per-log-site feature, it is a cool
feature, but made somewhat useless by this weird command line syntax.

Kind Regards, Thomas


>
> If a logging call is tagged with two tags A and B, I would have thought
> the default behaviour of "-Xlog:A" is to log all calls tagged at least with
> A, not all calls which are solely tagged with A and nothing else. I could
> not even think ot a use case for the latter.
>
> After some searching, I found that the behaviour I want and I would think
> makes sense as default is "-Xlog:A*".
>
> This also means that log lines will be mysteriously disappearing from
> output if someone adds another tag to that line, unless I always use an
> asterix? Or am I just slow to understand the command line syntax?
>
> Kind Regards, Thomas
>
>
>
>
>
>
> On Tue, Feb 23, 2016 at 6:52 PM, Marcus Larsson <marcus.larsson at oracle.com
> > wrote:
>
>> Hi,
>>
>> On 2016-02-22 17:54, 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/
>>>
>>
>> It might be a good idea to add a 'thread' tag and use that in addition to
>> the os tag for these messages. It would allow easy filtering of these
>> messages for those interested/uninterested. Just 'os' alone is quite a wide
>> area.
>>
>> Thanks,
>> Marcus
>>
>>
>> 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
>>>
>>
>>
>
>