VirtualBox

Ticket #2869 (closed defect: fixed)

Opened 1 year ago

Last modified 2 months ago

Debian host, Debian guest: rdtsc goes backwards -> fixed in SVN/3.0.6

Reported by: markusl Assigned to:
Priority: major Component: VMM/HWACCM
Version: VirtualBox 3.0.4 Keywords: rdtsc backwards
Cc: Guest type: Linux
Host type: Linux

Description

On Debian Lenny on a real PC, the attached program (rdtsc.cpp) works as expected. On Debian Lenny in VirtualBox 2.1.0 on Debian Lenny, the same program aborts after a few hundred thousand iterations, showing that rdtsc occasionally goes backwards. I've attached some sample output in output.txt.

If we ignore wrapping, rdtsc should only increase; it should never decrease.

Attachments

rdtsc.cpp (1.0 kB) - added by markusl on 2008-12-23 14:16:30.
Demonstration program, to be compiled with G++
output.txt (0.7 kB) - added by markusl on 2008-12-23 14:17:40.
Sample output when this program is run inside VirtualBox
VBox.log (41.2 kB) - added by markusl on 2008-12-23 14:34:30.
VBox.log, as requested

Change History

2008-12-23 14:16:30 changed by markusl

  • attachment rdtsc.cpp added.

Demonstration program, to be compiled with G++

2008-12-23 14:17:40 changed by markusl

  • attachment output.txt added.

Sample output when this program is run inside VirtualBox

2008-12-23 14:31:02 changed by sandervl73

Attach your VBox.log too please.

2008-12-23 14:34:30 changed by markusl

  • attachment VBox.log added.

VBox.log, as requested

2009-01-05 11:37:43 changed by frank

  • owner changed.
  • component changed from other to VMM.

2009-01-05 21:52:33 changed by frank

  • owner changed.
  • component changed from VMM to VMM/HWACCM.

Problem reproduced. Does not happen if VT-x / AMD-V is disabled.

2009-08-14 15:07:12 changed by sandervl73

  • summary changed from Debian host, Debian guest: rdtsc goes backwards to Debian host, Debian guest: rdtsc goes backwards -> fixed in SVN/3.0.6.

2009-08-14 15:07:26 changed by sandervl73

  • version changed from VirtualBox 2.1.0 to VirtualBox 3.0.4.

2009-09-10 08:25:38 changed by frank

  • status changed from new to closed.
  • resolution set to fixed.

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