Re: disappointing speed with virtio_blk

[Marcelo Tosatti <mtosatti@redhat.com>]

Hi Gerd,

On Fri, Apr 18, 2008 at 11:27:58PM +0200, Gerd von Egidy wrote:
> Hi Marcelo,
> 
> > > > 
> http://www.mail-archive.com/kvm-devel@lists.sourceforge.net/msg14732.html
> > >
> > > I tried it this evening with kvm 66 - which should include your patch,
> > > right?
> >
> > No its not included. The issue is being worked on.
> 
> my bad, sorry.
> 
> Now I know I really have that patch: qemu-kvm hangs :(
> 
> I was trying kvm 66 with only the patch listed above applied on an otherwise 
> perfectly working vm with virtio_blk root partition:
> 
> Last line of the booting kernel in my vnc window:
> 
> Serial: 8250/16550 driver $Revision 1.90... (you know the rest)

When the hang happens, can you run kvm-stat --once (script can be found
kvm-66 directory) and paste the result?

Can you confirm that reverting the patch fixes it?

> an strace of the qemu-kvm gave the following in rapid succession:
> 
> clock_gettime(CLOCK_MONOTONIC, {2565, 306799672}) = 0
> clock_gettime(CLOCK_MONOTONIC, {2565, 307065342}) = 0
> clock_gettime(CLOCK_MONOTONIC, {2565, 307354930}) = 0
> clock_gettime(CLOCK_MONOTONIC, {2565, 307618803}) = 0
> clock_gettime(CLOCK_MONOTONIC, {2565, 307886312}) = 0
> timer_gettime(0, {it_interval={0, 0}, it_value={0, 0}}) = 0
> timer_settime(0, 0, {it_interval={0, 0}, it_value={0, 33000000}}, NULL) = 0
> rt_sigtimedwait([USR1 USR2 ALRM IO], {si_signo=SIGALRM, si_code=SI_TIMER, 
> si_pid=0, si_uid=0, si_value={int=0, ptr=0}}, 0xbfe5af88, 8) = 14
> rt_sigaction(SIGALRM, NULL, {0x804d8f8, ~[KILL STOP RTMIN RT_1], 0}, 8) = 0

This won't help much.


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