Am 11.05.2015 9:42 nachm. schrieb Anton Ivanov <anton.iva...@kot-begemot.co.uk>: > > On 11/05/15 18:41, Thomas Meyer wrote: > > Am 11.05.2015 7:31 nachm. schrieb Anton Ivanov > > <anton.iva...@kot-begemot.co.uk>: > >> On 11/05/15 18:20, Anton Ivanov wrote: > >>> On 11/05/15 18:00, Thomas Meyer wrote: > >>>> Hi, > >>>> > >>>> maybe there is a bug in how the timers are created for all user space > >>>> processes. > >>>> In the latest patch I use os__timer_remain for the initial interval. > >>>> The idea was to launch all timers at the same time. But I now think this > >>>> can never work using relative times, especially when os__timer_remain > >>>> returns 0, then the new timer is never launched. > >>> That is not a bad idea, just requires a more complex check in setting up > >>> interval so it is reset to default when a zero value or value > HZ is > >>> passed. > >>> > >>> > >>>> That may explain the hangs you see. > >>>> You could try to replace os__timer_remain with the current HZ value > >>>>in nanoseconds. > >>> I am going to adjust time.c instead as above. > >> Both approaches fail - the check (that is expected actually, I did not > >> think properly here - it does not cover the stub in kernel/skas) and the > >> setting of data to the correct initial values. > >> > >> Also, if it was just not starting timers it would have been possible to > >> beat the process with USR2 on the head until its morale improves. Well, > >> "while true; do kill -USR2 PID ; done" does not change the behavior, it > >> still hangs and is still possible to terminate the errant process by > >> sending SIGSEGV to the UML thread which is shown as 100% CPU and in R > >> state. > > Yes, sending USR2 should do the same. Correct. > > > >> Problem is somewhere else. I am surprised it worked correctly in the > >> original one as there for 100% flat CPU usage it should have converged > >> to a behavior which is similar to what we have now. > > Mhh. Strange. Any hints how I can reproduce this? > > > > I need to see the same behaviour, i.e. the hang on my machine to begin to > > understand what is going on here. > > Start off with a Debian image of let's say wheezy and hit it with a > dist-upgrade to the next release. This produces enough IO+CPU at the > same time to trigger it. I get it 100% reproducible every time it tries > to unpack the first couple of packages.
Okay, I'll try that! > > I tried to trigger backtraces but could not get anything informative. > The old trick of hitting the kernel with SIGILL which worked very nicely > in older kernel versions no longer works :( You may can trigger an backtrace via uml_console. > > > > > Thanks for testing Anton. > > I wish I had more time at the moment to debug it and fix it :( We are > nearly there and it is worth it. Yes, same here. But we will finish this! > > A. > > > > > > >> A. > >> > >>> A. > >>> > >>>> Kind regards > >>>> Thomad > >>>> > >>>> A > >>> [snip] > >>> > >>> A. > >>> > >>> ------------------------------------------------------------------------------ > >>> > >>> One dashboard for servers and applications across Physical-Virtual-Cloud > >>> Widest out-of-the-box monitoring support with 50+ applications > >>> Performance metrics, stats and reports that give you Actionable Insights > >>> Deep dive visibility with transaction tracing using APM Insight. > >>> http://ad.doubleclick.net/ddm/clk/290420510;117567292;y > >>> _______________________________________________ > >>> User-mode-linux-devel mailing list > >>> User-mode-linux-devel@lists.sourceforge.net > >>> https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel > >>> > >> > >> ------------------------------------------------------------------------------ > >> > >> One dashboard for servers and applications across Physical-Virtual-Cloud > >> Widest out-of-the-box monitoring support with 50+ applications > >> Performance metrics, stats and reports that give you Actionable Insights > >> Deep dive visibility with transaction tracing using APM Insight. > >> http://ad.doubleclick.net/ddm/clk/290420510;117567292;y > >> _______________________________________________ > >> User-mode-linux-devel mailing list > >> User-mode-linux-devel@lists.sourceforge.net > >> https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel > > > ------------------------------------------------------------------------------ > > One dashboard for servers and applications across Physical-Virtual-Cloud > Widest out-of-the-box monitoring support with 50+ applications > Performance metrics, stats and reports that give you Actionable Insights > Deep dive visibility with transaction tracing using APM Insight. > http://ad.doubleclick.net/ddm/clk/290420510;117567292;y > _______________________________________________ > User-mode-linux-devel mailing list > User-mode-linux-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel ------------------------------------------------------------------------------ One dashboard for servers and applications across Physical-Virtual-Cloud Widest out-of-the-box monitoring support with 50+ applications Performance metrics, stats and reports that give you Actionable Insights Deep dive visibility with transaction tracing using APM Insight. http://ad.doubleclick.net/ddm/clk/290420510;117567292;y _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel
