VirtualBox

Ticket #2869 (closed defect: fixed)

Opened 5 years ago

Last modified 5 years ago

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

Reported by: markusl Owned by:
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 Download (1.0 KB) - added by markusl 5 years ago.
Demonstration program, to be compiled with G++
output.txt Download (706 bytes) - added by markusl 5 years ago.
Sample output when this program is run inside VirtualBox
VBox.log Download (41.2 KB) - added by markusl 5 years ago.
VBox.log, as requested

Change History

Changed 5 years ago by markusl

Demonstration program, to be compiled with G++

Changed 5 years ago by markusl

Sample output when this program is run inside VirtualBox

comment:1 Changed 5 years ago by sandervl73

Attach your VBox.log too please.

Changed 5 years ago by markusl

VBox.log, as requested

comment:2 Changed 5 years ago by frank

  • Component changed from other to VMM

comment:3 Changed 5 years ago by frank

  • Component changed from VMM to VMM/HWACCM

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

comment:4 Changed 5 years ago 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

comment:5 Changed 5 years ago by sandervl73

  • Version changed from VirtualBox 2.1.0 to VirtualBox 3.0.4

comment:6 Changed 5 years ago by frank

  • Status changed from new to closed
  • Resolution set to fixed
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