Poor console performance in Windows 7
Affects | Status | Importance | Assigned to | Milestone | |
---|---|---|---|---|---|
QEMU |
Fix Released
|
Undecided
|
Unassigned |
Bug Description
As part of its conformance test suite, Wine tests the behavior of the Windows console API. Part of this test involves opening a test console and scrolling things around. The test probably does not need to perform that many scroll operations to achieve its goal. However as is it illustrates a significant performance issue in QEmu. Unfortunately it does so by timing out (the tests must run in less than 2 minutes). Here are the run times on a few configurations:
10s - QEmu 1.4 + Q9450@2.6GHz + Windows XP + QXL + QXL driver
8s - QEmu 1.12 + Opteron 6128 + Windows XP + QXL + QXL driver
127s - QEmu 1.12 + Opteron 6128 + Windows 7 + cirrus + vga driver
127s - QEmu 1.12 + Opteron 6128 + Windows 7 + QXL + QXL driver
147s - QEmu 1.12 + Opteron 6128 + Windows 7 + vmvga + vga driver
145s - QEmu 1.12 + Opteron 6128 + Windows 7 + vmvga + vmware driver (xpdm, no better with all graphics effects disabled)
10s - Metal + Atom N270 + Windows XP + GMA 950 + Intel driver
6s - Metal + i5-3317U + Windows 8 + HD4000 + Intel driver
3s - VMware + Q9450@2.6GHz + Windows XP + vmvga + vmware driver
65s - VMware + Q9450@2.6GHz + Windows 7 + vmvga + vmware driver
So when running on the bare metal all versions of Windows are about as fast. However in QEmu Windows 7 is almost 16 times slower than Windows XP! VMware is impacted too but it's still maintains a good lead in performance.
Disabling all graphics effects did not help so it's not clear that the fault lies with Windows 7's compositing desktop window manager. Maybe it has to do with the lack of a proper wddm driver?
Changed in qemu: | |
status: | Incomplete → Fix Released |
Triaging old bug tickets... can you still reproduce this issue with the latest version of QEMU? Or could we close this ticket nowadays?