RFR [XS] : 8204598 : add more thread-related system settings info to hs_error file on Linux

[Thomas Stüfe]

Looks good to me. Thanks!
.. Thomas

On Fri, Jun 8, 2018, 14:22 Baesken, Matthias <matthias.baesken at sap.com>
wrote:

> Hi Thomas / David , thanks for the reviews .
>
> Thomas,  I created a second webrev   (renamed  the function to
> print_proc_sys_info  and changed the output slightly )  :
>
> http://cr.openjdk.java.net/~mbaesken/webrevs/8204598.1/
>
> Best regards, Matthias
>
>
> > -----Original Message-----
> > From: Thomas Stüfe [mailto:thomas.stuefe at gmail.com]
> > Sent: Freitag, 8. Juni 2018 11:43
> > To: Baesken, Matthias <matthias.baesken at sap.com>
> > Cc: hotspot-dev at openjdk.java.net
> > Subject: Re: RFR [XS] : 8204598 : add more thread-related system settings
> > info to hs_error file on Linux
> >
> > Hi Matthias,
> >
> >
> > Thanks for that change, this is useful.
> >
> > --
> >
> > I do not like lumping max_map_count together with the other variables
> > in ".._thread_info" since it has nothing to do with threads.
> >
> > I would probably just rename the function to something different (e.g.
> > "print_procs_sys_info" as in "print information taken from kernel
> > variables in /proc/sys...") or spread them to other functions.
> >
> > --
> >
> > I dislike the "out->print("\n....\n") style. Could you please
> > reformulate like this:
> >
> > out->cr();
> > out->print_cr("...");
> >
> > to make newlines more explicit?
> >
> > --
> >
> > Can you please reformulate:
> >
> > "kernel system-wide limit on the number of threads" -> "system-wide
> > limit on the number of kernel threads" or just "system-wide limit on
> > the number of threads"
> > "maximum number of unique process identifiers the system can support)"
> > -> "system-wide limit on number of process identifiers"
> >
> > Thank you!
> >
> > Thomas
> >
> >
> >
> >
> > On Fri, Jun 8, 2018 at 10:04 AM, Baesken, Matthias
> > <matthias.baesken at sap.com> wrote:
> > > Hi could you please review  this small Linux related change ?
> > >
> > > In linux os::print_os_info ,  I  print additional  info about a number
> of
> > system parameters influencing thread creation on Linux.
> > >
> > > We noticed the influence of these parameters when looking into an
> > application creating over 10.000 threads on Linux at the same time;
> there we
> > got an OOM : unable to create new native thread
> > > which was caused by a failing pthread_create (error EAGAIN) .
> > >
> > > The machine had plenty of memory, so we looked into various kernel
> > params and in the end noticed that /proc/sys/kernel/pid_max was too low.
> > > The other added parameters "threads-max" and "max_map_count" are
> > also known to be related to problems when running with high thread
> > numbers, so I add them too .
> > >
> > >
> > >
> > > Webrev :
> > >
> > > http://cr.openjdk.java.net/~mbaesken/webrevs/8204598/
> > >
> > > Bug :
> > >
> > > https://bugs.openjdk.java.net/browse/JDK-8204598
> > >
> > >
> > > Thanks, Matthias
> > >
>