Ticket #2869 (closed defect: fixed)
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
(1.0 KB) -
added by markusl 9 years ago.
- Demonstration program, to be compiled with G++
-
output.txt
(706 bytes) -
added by markusl 9 years ago.
- Sample output when this program is run inside VirtualBox
-
VBox.log
(41.2 KB) -
added by markusl 9 years ago.
- VBox.log, as requested
Change History
Changed 9 years ago by markusl
-
attachment
output.txt
added
Sample output when this program is run inside VirtualBox
comment:3 Changed 9 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 9 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
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Demonstration program, to be compiled with G++