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

Coleen Phillimore coleen.phillimore at oracle.com
Wed Feb 24 12:30:30 UTC 2016



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 
> <http://cr.openjdk.java.net/%7Estuefe/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
>
> 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 <mailto: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/
>         <http://cr.openjdk.java.net/%7Estuefe/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
>
>
>



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