VirtualBox

Opened 15 years ago

Closed 15 years ago

#2869 closed defect (fixed)

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

Reported by: Markus Laker Owned by:
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 (3)

rdtsc.cpp (1.0 KB ) - added by Markus Laker 15 years ago.
Demonstration program, to be compiled with G++
output.txt (706 bytes ) - added by Markus Laker 15 years ago.
Sample output when this program is run inside VirtualBox
VBox.log (41.2 KB ) - added by Markus Laker 15 years ago.
VBox.log, as requested

Download all attachments as: .zip

Change History (9)

by Markus Laker, 15 years ago

Attachment: rdtsc.cpp added

Demonstration program, to be compiled with G++

by Markus Laker, 15 years ago

Attachment: output.txt added

Sample output when this program is run inside VirtualBox

comment:1 by Sander van Leeuwen, 15 years ago

Attach your VBox.log too please.

by Markus Laker, 15 years ago

Attachment: VBox.log added

VBox.log, as requested

comment:2 by Frank Mehnert, 15 years ago

Component: otherVMM

comment:3 by Frank Mehnert, 15 years ago

Component: VMMVMM/HWACCM

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

comment:4 by Sander van Leeuwen, 15 years ago

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

comment:5 by Sander van Leeuwen, 15 years ago

Version: VirtualBox 2.1.0VirtualBox 3.0.4

comment:6 by Frank Mehnert, 15 years ago

Resolution: fixed
Status: newclosed
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