Avi Kivity schrieb:
On 05/19/2010 12:57 PM, Udo Lembke wrote:
Jan Kiszka schrieb:
...
--enable-io-thread?
If you had it disabled, it would also answer my question if -smp works
without problems without that feature.
Jan
Hi,
i have a dumb question: what is the "--enable-io-thread"? Is this a
kvm-switch?
It's a ./configure switch for upstream qemu (don't use with qemu-kvm
yet).
My kvm 0.12.4 don't accept this switch. I'm know only "threads=n" as
smp-parameter and "aio=threads" as drive-parameter.
Because i look for a solution for a better io-performance of
windows-guest with more than one cpu...
Unrelated, what are your smp issues?
If i use one cpu i got a good io-performance:
e.g. over 500MB/s at the profile "install" of the io-benchmark h2benchw.exe.
( aio=threads | SAS-Raid-0 | ftp://ftp.heise.de/pub/ct/ctsi/h2benchw.zip
| hwbenchw.exe -p -w iotest 0)
The same test but with two cpus gives results between 27 and 298 MB/s!
Also in real life it's noticeable not only with an benchmark. I use a
win-vm with two cpu for postscript-ripping and have a performance drop
due to the bad io.
Udo
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