CPU change causes hanging of .NET apps
Hi all,
when changing the CPU from the default QEMU32 one to e.g. the n270 or the core2duo no .NET apps will work under Windows XP as guest. Switching back and everything is fine. The Pentium Emulation on the other side works fine!
The Application loads but it hangs with 99% CPU usage and ca. 3-4 MB Memory
Consumption.
Normally, .NET is capable to run on all x86 Processors >= Pentium. XP and non-.NET Apps work fine.
Any Ideas what happens here? I also started applications that were NOT started with the QEMU32 CPU to prevent a caching - same problem.
Best regards,
Erik
Quoted 2 lines · Erik Rull
Any Ideas what happens here? I also started applications that were NOT started with the QEMU32 CPU to prevent a caching - same problem.
just a couple guesses:
- maybe there's some JIT'ed code cached somewhere in the filesystem
- maybe the exact code generator is chosen at startup time, or even at .NET installation time.
in short, if restarting windows doesn't fix it, i would reinstall .NET, or maybe the whole HAL
Signature · 1 line
Javier
Quoted 5 lines · On Wednesday 28 October 2009 16:13:37 Erik Rull wrote:
Hi all,
when changing the CPU from the default QEMU32 one to e.g. the n270 or the core2duo no .NET apps will work under Windows XP as guest. Switching back and everything is fine. The Pentium Emulation on the other side works fine!
Have you tried with -cpu core2duo,-nx ?
--Iggy
Quoted 18 lines
The Application loads but it hangs with 99% CPU usage and ca. 3-4 MB Memory
Consumption.Normally, .NET is capable to run on all x86 Processors >= Pentium. XP and non-.NET Apps work fine.
Any Ideas what happens here? I also started applications that were NOT started with the QEMU32 CPU to prevent a caching - same problem.
Best regards,
Erik
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Quoted 10 lines · Erik Rull
Hi all,
when changing the CPU from the default QEMU32 one to e.g. the n270 or the core2duo no .NET apps will work under Windows XP as guest. Switching back and everything is fine. The Pentium Emulation on the other side works fine!
The Application loads but it hangs with 99% CPU usage and ca. 3-4 MB Memory Consumption.
Normally, .NET is capable to run on all x86 Processors >= Pentium. XP and non-.NET Apps work fine.
Any Ideas what happens here? I also started applications that were NOT started with the QEMU32 CPU to prevent a caching - same problem.
What's your host cpu type?
Signature · 1 line
error compiling committee.c: too many arguments to function
Hi Avi,
the Host CPU is a Intel Core2Duo - VT capable and enabled!
Best regards,
Erik
Quoted 14 lines · Avi Kivity
Quoted 10 lines · Erik Rull
Hi all,
when changing the CPU from the default QEMU32 one to e.g. the n270 or the core2duo no .NET apps will work under Windows XP as guest. Switching back and everything is fine. The Pentium Emulation on the other side works fine!
The Application loads but it hangs with 99% CPU usage and ca. 3-4 MB Memory Consumption.
Normally, .NET is capable to run on all x86 Processors >= Pentium. XP and non-.NET Apps work fine.
Any Ideas what happens here? I also started applications that were NOT started with the QEMU32 CPU to prevent a caching - same problem.
What's your host cpu type?
Quoted 2 lines · Erik Rull
Hi Avi,
Please don't top-post.
Quoted 1 line
the Host CPU is a Intel Core2Duo - VT capable and enabled!
The problem is that one of the flags that -cpu core2duo enables is implemented incorrectly, so it leads to .net breakage.
These flags are pni, lm, nx, ssse3, syscall.
Please try -cpu core2duo,-pni,-lm,-nx,-ssse3,-syscall. If it works, remove features one by one until it doesn't and let us know the results.
Signature · 1 line
Do not meddle in the internals of kernels, for they are subtle and quick to panic.
Quoted 6 lines · Avi Kivity
Quoted 2 lines · Erik Rull
Hi Avi,
Please don't top-post.
Quoted 7 lines
Quoted 1 line
the Host CPU is a Intel Core2Duo - VT capable and enabled!
The problem is that one of the flags that -cpu core2duo enables is implemented incorrectly, so it leads to .net breakage.
These flags are pni, lm, nx, ssse3, syscall.
Please try -cpu core2duo,-pni,-lm,-nx,-ssse3,-syscall. If it works, remove features one by one until it doesn't and let us know the results.
I took all flags, same effect as without all of these flags. :(
Any other idea?
- Erik
Quoted 4 lines · Erik Rull
I took all flags, same effect as without all of these flags. :(
Any other idea?
It's probably the cache size query.
Does -cpu host work?
Signature · 1 line
error compiling committee.c: too many arguments to function
2009/11/3 Avi Kivity <[email protected]>:
Quoted 10 lines · Erik Rull
Quoted 4 lines
I took all flags, same effect as without all of these flags. :(
Any other idea?
It's probably the cache size query.
Does -cpu host work?
My totally noob in QEMU guess -
my bet it's CR4.OSFXSR which is controlled by presence of cpuid.1.edx[24] - FXSR bit (FXSAVE and FXRSTOR) instructions.
I'm curious - is there any way in QEMU to redefine returned cpuid leaf values? It will be interesting to see results if that given bit will be disabled in configuration.
Best Regards,
Timur
Quoted 5 lines · Timur Safin
My totally noob in QEMU guess -
my bet it's CR4.OSFXSR which is controlled by presence of cpuid.1.edx[24] - FXSR bit (FXSAVE and FXRSTOR) instructions.
That would affect floating point as well.
Quoted 4 lines
I'm curious - is there any way in QEMU to redefine returned cpuid leaf values? It will be interesting to see results if that given bit will be disabled in configuration.
qemu -cpu host,-flag
Signature · 1 line
error compiling committee.c: too many arguments to function
Quoted 7 lines · Avi Kivity
Quoted 5 lines · Timur Safin
My totally noob in QEMU guess -
my bet it's CR4.OSFXSR which is controlled by presence of cpuid.1.edx[24] - FXSR bit (FXSAVE and FXRSTOR) instructions.
Quoted 9 lines
That would affect floating point as well.
Quoted 4 lines
I'm curious - is there any way in QEMU to redefine returned cpuid leaf values? It will be interesting to see results if that given bit will be disabled in configuration.
qemu -cpu host,-flag
I tried that value, result is an error:
Unable to find x86 CPU definition
- Erik
Quoted 6 lines · Erik Rull
Quoted 2 lines
qemu -cpu host,-flag
I tried that value, result is an error:
Unable to find x86 CPU definition
Please use qemu-kvm.git for this test.
Signature · 1 line
error compiling committee.c: too many arguments to function