Re: [Qemu-devel] Windows slow boot: contractor wanted

[Richard Davies]

Hi Avi,

Thanks to you and several others for offering help. We will work with Avi at
first, but are grateful for all the other offers of help. We have a number
of other qemu-related projects which we'd be interested in getting done, and
will get in touch with these names (and anyone else who comes forward) to
see if any are of interest to you.


This slow boot problem is intermittent and varys in how slow the boots are,
but I managed to trigger it this morning with medium slow booting (5-10
minutes) and link to the requested traces below.

The host in question has 128GB RAM and dual AMD Opteron 6128 (16 cores
total). It is running kernel 3.5.1 and qemu-kvm 1.1.1.

In this morning's test, we have 3 guests, all booting Windows with 40GB RAM
and 8 cores each (we have seen small VMs go slow as I originally said, but
it is easier to trigger with big VMs):

pid 15665: qemu-kvm -nodefaults -m 40960 -smp 8 -cpu host,hv_relaxed \
  -vga cirrus -usbdevice tablet -vnc :99 -monitor stdio -hda test1.raw
pid 15676: qemu-kvm -nodefaults -m 40960 -smp 8 -cpu host,hv_relaxed \
  -vga cirrus -usbdevice tablet -vnc :98 -monitor stdio -hda test2.raw
pid 15653: qemu-kvm -nodefaults -m 40960 -smp 8 -cpu host,hv_relaxed \
  -vga cirrus -usbdevice tablet -vnc :97 -monitor stdio -hda test3.raw

We are running with hv_relaxed since this was suggested in the previous
thread, but we see intermittent slow boots with and without this flag.


All 3 VMs are booting slowly for most of the attached capture, which I
started after confirming the slow boots and stopped as soon as the first of
them (15665) had booted. In terms of visible symptoms, the VMs are showing
the Windows boot progress bar, which is moving very slowly. In top, the VMs
are at 400% CPU and their resident state size (RES) memory is slowly
counting up until it reaches the full VM size, at which point they finish
booting.


Here are the trace files:

http://users.org.uk/slow-win-boot-1/ps.txt (ps auxwwwf as root)
http://users.org.uk/slow-win-boot-1/top.txt (top with 2 VMs still slow)
http://users.org.uk/slow-win-boot-1/trace-console.txt (running trace-cmd)
http://users.org.uk/slow-win-boot-1/trace.dat (the 1.7G trace data file)
http://users.org.uk/slow-win-boot-1/trace-report.txt (the 4G trace report)


Please let me know if there is anything else which I can provide?

Thank you,

Richard.