3rd Request Re: 2nd request -- Re: [Xen-users] QueryPerformaceCounter and TSC returns bad results with Windows HVM

[James Miller <jimm@xxxxxxxxxxxxxxx>]

James Miller wrote:
> James Miller wrote:
> > Hi everyone,
> >
> > We have a server with 2 sockets, 4 cores each, running CentOS release 
> > 5 (Final) and Xen 3.0.3. On that server we have 7 Windows 2003 
> > DomUs.  We've locked each one to a specific core and each has a 
> > single CPU HAL. We have an application which uses 
> > QueryPerformanceCounter.  On very rare occasions a call to QPC 
> > returns a bad result causing our processes to disconnect from the 
> > server.
> > I've read about some bugs with HPC
> > http://bugzilla.xensource.com/bugzilla/show_bug.cgi?id=1291
> > I've also read something about not using APCI somewhat mitigates this 
> > issue.
> > Could someone tell me if this issues is being or has been resolved by 
> > later versions of Xen?
> > I have, below, a sample configuration of a Windows HVM DomU as well 
> > as the output of xm vcpu-list. Please let me know if there is any 
> > additional information I can provide to help resolve this issue and I 
> > greatly appreciate all your help.
> >
> > Sample config
> > import os, re
> > arch = os.uname()[4]
> > if re.search('64', arch):
> >    arch_libdir = 'lib64'
> > else:
> >    arch_libdir = 'lib'
> > name = 'evalvm01.vm'
> > kernel = '/usr/lib/xen/boot/hvmloader'
> > builder='hvm'
> > boot='c'
> > memory = 2048
> > vif = [ 'type=ioemu, vifname=vifevalvm01,  mac=aa:00:ef:39:a0:08 
> > ,bridge=xenbr1' ]
> > device_model = '/usr/' + arch_libdir + '/xen/bin/qemu-dm'
> > vnc=1
> > sdl=0
> > vcpus = 1
> > cpus ="1"
> > vnclisten='0.0.0.0'
> > vncpasswd='xxxxxxxxxx'
> > disk = [ 'phy:/dev/vg01/evalvm01,ioemu:hda,w']
> > acpi=1
> > vncunused=1
> > vncdisplay=1
> >
> > xm vcpu-list
> > Name                              ID VCPUs   CPU State   Time(s) CPU 
> > Affinity
> > Domain-0                           0     0     0   r--  2794806.2 0
> > Domain-0                           0     1     -   --p       2.0 any cpu
> > Domain-0                           0     2     -   --p       1.1 any cpu
> > Domain-0                           0     3     -   --p       1.4 any cpu
> > Domain-0                           0     4     -   --p       0.9 any cpu
> > Domain-0                           0     5     -   --p       0.9 any cpu
> > Domain-0                           0     6     -   --p       0.8 any cpu
> > Domain-0                           0     7     -   --p       0.9 any cpu
> > evalvm01.vm                      118     0     1   -b-   27903.4 1
> > evalvm02.vm                      112     0     2   -b-   10507.8 2
> > evalvm03.vm                      113     0     3   -b-    2445.3 3
> > evalvm04.vm                      116     0     4   -b-   79872.1 4
> > evalvm05.vm                      119     0     5   -b-   38717.1 5
> > evalvm06.vm                      115     0     6   -b-   98750.3 6
> > evalvm07.vm                      117     0     7   r--   65222.2 7
> >
> >
> > Jim
> Hi everyone,
>
> I hate to be a pest but this is becoming a _REAL_ show stopper for us 
> going forward with using Xen.  I would appreciate any thoughts, if I'm 
> asking in the wrong way or not providing enough info _PLEASE_ let me 
> know.
> About the only other thing I can offer is that the problem happens 
> very infrequently but when it does the process will report, for 
> example, that it went 2,451,046ms w/out talking to the server that's 
> like ~40min meaning the QPC gave an erroneous response.  Almost as if 
> a 64bit counter (I think it's a 64bit counter) was rolling over?.!
> Anyway, thanks in advance for any suggestions or assistance
>
> Jim
Soooo one of our programmers wrote a little program to test the issue 
and here's the results:
C:\RS>qpc_test.exe
FREQUENCY = 3579545 cycles per second (369E99)
COUNTER = 26206348760 cycles (61A0525D8)
THRESHOLD exceeded: diff= 8589970453, threshold = 500, threshold * freq 
/ 1000 =
1789772
THRESHOLD exceeded: last_counter = 749471789887, this_Counter = 758061760340



CAN ANYONE PLEASE COMMENT ON THIS ISSUE? 

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