Re: [gentoo-server] DomU freezes in the middle of booting [SOLVED]

[Konstantin]

Hello Pandu,

Thursday, April 12, 2012, 17:30:08, Pandu Poluan wrote:
> On Apr 12, 2012 8:51 PM, "Konstantin" <konstantin@××××××××.com> wrote:
>> Thursday, April 12, 2012, 15:52:50, Konstantin wrote:
>> > Thursday, April 12, 2012, 15:29:42, Pandu Poluan wrote:
>> >>> Thursday, April 12, 2012, 13:09:15, Pandu Poluan wrote:
>> >>> > Have you tried:
>> >>> > root   = '/dev/xvda1'
>> >>> > That is, without 'ro'?
>> >>> > Rgds,
>> >>>
>> >>> Thank you. Already tried without any difference.
>> >>>
>> >> It's a DomU, right? Why do you have Dom0 option enabled?
>>
>> > You mean this part of .config file:
>> > CONFIG_XEN_DOM0=y
>> > CONFIG_XEN_PRIVILEGED_GUEST=y
>> > CONFIG_XEN_PVHVM=y
>> > CONFIG_XEN_MAX_DOMAIN_MEMORY=128
>> > CONFIG_XEN_SAVE_RESTORE=y
>>
>> > I just could not find how to disable this code in menuconfig. :)
>>
>> If I'm trying to turn it off, but then other frontend options
>> disappear.
>>
>> Latest update: When I saw
>> ---------------------
>>  * Starting local
>>  [ ok ]
>> ---------------------
>>
>> I've noticed that domU actually working. I've tried to change inittab
>> remotely via ssh to something like
>>
>> # TERMINALS
>> x1:12345:respawn:/sbin/agetty 38400 console linux
>> #c1:12345:respawn:/sbin/agetty 38400 tty1 linux
>> #c2:2345:respawn:/sbin/agetty 38400 tty2 linux
>> #c3:2345:respawn:/sbin/agetty 38400 tty3 linux
>> #c4:2345:respawn:/sbin/agetty 38400 tty4 linux
>> #c5:2345:respawn:/sbin/agetty 38400 tty5 linux
>> #c6:2345:respawn:/sbin/agetty 38400 tty6 linux
>>
>> Then reinitialized init by
>> localhost ~ # init q
>>
>> and console in Dom0 become interactive again. So that freezing after
>> "Starting local" was the console problem anyway.
>>
>> Right now only one left with that random start. DomU starts
>> successfully about one time per three unsuccessful.
>>
>> I've noticed that it gets stuck when kernel outputs this text:
>>
>> -------------------------------------------------------------
>> Switching to clocksource xen
>> pnp: PnP ACPI: disabled
>> CE: xen increased min_delta_ns to 150000 nsec
>> CE: xen increased min_delta_ns to 225000 nsec
>> CE: xen increased min_delta_ns to 337500 nsec
>> CE: xen increased min_delta_ns to 506250 nsec
>> CE: xen increased min_delta_ns to 759375 nsec
>> CE: xen increased min_delta_ns to 1139062 nsec
>> CE: xen increased min_delta_ns to 1708593 nsec
>> CE: xen increased min_delta_ns to 2562889 nsec
>> CE: xen increased min_delta_ns to 3844333 nsec
>> CE: xen increased min_delta_ns to 5766499 nsec
>> CE: xen increased min_delta_ns to 8649748 nsec
>> CE: xen increased min_delta_ns to 10000000 nsec
>> CE: Reprogramming failure. Giving up
>> CE: Reprogramming failure. Giving up
>> hrtimer: interrupt took 5171 ns
>> TCP bind hash table entries: 65536 (order: 8, 1048576 bytes)
>> TCP: Hash tables configured (established 131072 bind 65536)
>> TCP reno registered
>> UDP hash table entries: 512 (order: 2, 16384 bytes)
>> UDP-Lite hash table entries: 512 (order: 2, 16384 bytes)
>> CE: xen increased min_delta_ns to 150000 nsec
>> CE: xen increased min_delta_ns to 225000 nsec
>> CE: xen increased min_delta_ns to 337500 nsec
>> CE: xen increased min_delta_ns to 506250 nsec
>> CE: xen increased min_delta_ns to 759375 nsec
>> CE: xen increased min_delta_ns to 1139062 nsec
>> CE: xen increased min_delta_ns to 1708593 nsec
>> CE: xen increased min_delta_ns to 2562889 nsec
>> CE: xen increased min_delta_ns to 3844333 nsec
>> CE: xen increased min_delta_ns to 5766499 nsec
>> CE: xen increased min_delta_ns to 8649748 nsec
>> CE: xen increased min_delta_ns to 10000000 nsec
>> CE: Reprogramming failure. Giving up
>> CE: Reprogramming failure. Giving up
>> platform rtc_cmos: registered platform RTC device (no PNP device found)
>> -------------------------------------------------------------
>>
>> And when kernel not writing any "CE: " messages domU boots
>> successfully:
>>
>> --------------------------------
>> PCI: System does not support PCI
>> PCI: System does not support PCI
>> Switching to clocksource xen
>> pnp: PnP ACPI: disabled
>> --------------------------------
>>
>> Trying to figure out what to do next.

> Try using "tickless". I forgot where exactly, but IIRC on the same page where you set the CPU type.
> Rgds,

If you mean Tickless System (Dynamic Ticks) as NO_HZ=y so it already
enabled for me.

I figured out how to solve my problem with DomU. I've changed tsc_mode
to something different from 0 or 4 and it seems started to work for
me.

Here is short tsc_mode option description from sample VM config file:

#----------------------------------------------------------------------------
#   tsc_mode : TSC mode (0=default, 1=native TSC, 2=never emulate, 3=pvrdtscp)
#   emulate TSC provides synced TSC for all vcpus, but lose perfomrance.
#   native TSC leverages hardware's TSC(no perf loss), but vcpu's TSC may lose
#    sync due to hardware's unreliable/unsynced TSC between CPUs.
#   default intelligently uses native TSC on machines where it is safe, but
#    switches to emulated if necessary after save/restore/migration
#   pvrdtscp is for intelligent apps that use special Xen-only paravirtualized
#    cpuid instructions to obtain offset/scaling/migration info and maximize
#    performance within pools of machines that support the rdtscp instruction
tsc_mode=1

BTW, does anybody has NTP server on a virtual machine? ;)

-- 
Konstantin