Re: [uml-devel] [PATCH] um: Switch clocksource to hrtimers

[Anton Ivanov <anton.ivanov@kot-begemot.co.uk>]

On 19/05/15 17:39, Richard Weinberger wrote:
> On Tue, May 19, 2015 at 6:19 PM, Anton Ivanov
> <anton.ivanov@kot-begemot.co.uk> wrote:
>> Same story.
>>
>> Overall works quite well, the moment I give it the "dselect upgrade
>> test" the userspace hangs.
>>
>> Kernel continues to work - forwarding, icmp, uml_mconsole are fine.
> Do you know where it hangs?
> Maybe the kernel does not get any scheduler tick and does not schedule a task..,

Kernel continues to get ticks, timers increment, io also works.

If I strace the kernel I see a mix of SIGALRM (or in the oder version 
-USR2), SIGIO and SIGCHLD. Nothing out of the ordinary.

Uml mconsole works. I cannot get meaningful information because trying 
to invoke backtraces I get "SIGSEGV in SIGSEGV handler" for all 
processes. Memory looks OK too - 500MB+ free on a 1GB UML.

Syncronous vs asynchronous FS does not change it so it is not a variety 
of the writeout bug.

If I could get a bt for the userspace task and/or its stub we could have 
nailed it. I suspect it is spinning in skas/process.c for some reason. 
No idea why, but it takes 100% CPU.

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