Re: [Xen-devel] mini-os under xen 3.0.2

[Grzegorz Milos <gm281@xxxxxxxxx>]

Hello there,

I've been away from the list for little to long I think. Still I hope  
I can be of help.
The README file is a bit out of date. Mini-OS periodically writes the  
current time, but the period is extremely long (as you correctly  
calculated it's about 3 hours). Still the domain should be up and  
running.
If the domain is responding to the console events (it should print:  
"No console input handler" every time you press Enter) everything is  
fine.
The reason why the timer event happens every 10 second is that idle  
Mini-OS domain is configured to block for periods of 10 seconds.  
However, if the domain receives console events if will be woken up  
more frequently (and thus the period between time printouts will be  
shorter).
The reason why you see pending timer events when using the console is  
as follows:
- Only running domains will respond to timer events. Since Mini-OS is  
blocked most of the time you will not handle the usual 10ms frequency  
events.
- As soon as the domain wakes up the timer event is delivered.
- Domain wakes up every time you press a key on the console. If the  
frequency of your key presses is less then 100 times a second you  
should see a pending event each time.
If you remove "block_domain(10000);" call from sched.c, the domain  
will never go to sleep. It will then handle all of the 10ms timer  
events. You should then see the printouts of the current time roughly  
every 10 seconds.
Cheers
Gregor



On 17 Jul 2006, at 20:10, Robert Kaiser (FH) wrote:

> Hello all,
>
> [My apologies if this question is misplaced here, I initially  
> posted it to
> xen-users but was told there that it might be better suited for xen- 
> devel..]
> I am just setting up Xen test/development environment and I have  
> successfully
> installed xen 3.0.2 on a dual celeron system. Linux in  dom0 works  
> fine. Now,
> I would like to play with the mini-os (my ultimate goal  is to  
> implement a
> small RTOS as guest in Xen, so mini-os looks like a good starting  
> point).
> However, I can't seem to get it to run as (I think) it  should: It  
> boots up,
> but as far as I understand the source code and the  README, it should
> continue by printing  the current time in regular  intervals, which  
> it does
> not. Here is the output I receive:
>
>
> ----------------------------------
>  Xen Minimal OS!
> start_info:   c001d000
>   nr_pages:   8192  shared_inf: 00be3000
>   pt_base:    c0020000  mod_start:  0x0
>   mod_len:    0
>   flags:      0x0
>   cmd_line:
> MM: Init
>   _text:        c0000000
>   _etext:       c0009577
>   _edata:       c000a604
>   stack start:  c0011e40
>   _end:         c00142a4
>   start_pfn:    25
>   max_pfn:      2000
> Mapping memory range 0xc0400000 - 0xc2000000
> MM: Initialise page allocator for c002c000(2c000)-c2000000(2000000)
> MM: done
> Initialising timer interface
> Initialising console ... done.
> Initialising scheduler, idle_thread 00000000
> Thread "Idle": pointer: 0xc002d00c, stack: 0xc002e000
> Thread "init_xs": pointer: 0xc002d034, stack: 0xc0030000
> Thread "xenstore": pointer: 0xc002d05c, stack: 0xc0032000
> Xenbus initialised.
> Thread "init_xs" exited.
> --------------------------------
>
> I have inserted some debug printk's into do_hypervisor_callback()  
> to see
> whether any callbacks are made at all. According to this, a vtimer  
> interrupt
> does happen, but only every 10 seconds, which -as I guess-  is far  
> less
> frequent than it should be (the timer handler prints out the  
> current time for
> every 1000th timer event, so it would take almost three hours  
> before the
> first message is printed). Also interesting is that whenever I hit  
> a key on
> the console, a timer event is almost always pending along along  
> with the
> console event. It looks like the timer event bit is properly set by  
> Xen, but
> the callback handler is not invoked.
>
> Does anyone have an idea what is wrong?
>
> Cheers
>
> Rob
>
> P.S.: BTW, I have also tried to use the mini-os in from xen- 
> untested. That one
> looks very different, but, alas, it does not even compile...
>
>
> _______________________________________________
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> Xen-devel@xxxxxxxxxxxxxxxxxxx
> http://lists.xensource.com/xen-devel
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