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Re: I was surprised to see Oops: Exception in kernel



On 4/19/20 2:14 PM, Romain Dolbeau wrote:
Le ven. 17 avr. 2020 à 02:30, Dennis Clarke <dclarke@blastwave.org> a écrit :
I have no idea how that works.

Normally it's the default, quoting the doc: "The default is to enable
multi-threading where both the back-end and front-ends support it and
no incompatible TCG features have been enabled (e.g. icount/replay)."

I see terrible horrific performance

You need some pretty fast host cores to get an interactively usable
emulated host. My home test system is a dual E5-2690v4...


I have a dedicated Intel i7 based machine with 16G DDR4 and Samsung
SSD's to run this instance. Exclusively. I did carefully walk through
systemd to remove services that are mostly useless anyways.


ppc64@styx:~$ ./ppc64le.sh

Is your host PPC64 as the username implies? I assume it's not PPC64LE
otherwise you'd run KVM rather than TCG, so PPC64BE ... I'm not sure
you can get MTTCG doing PPC64LE-on-PPC64BE... and most PPC64BE systems
are old and not particularly fast, emulating PPC64LE on them isn't
going to be fast :-(

Ha .. no way.  No.

That is just the username that runs the instance.

Also I did build qemu 5.0.0-rc3 with debug enabled and that will cause a
2x to 5x slow down I am told. However it did allow us to see an opcode
problem which has since been fixed and I re-built with the patch. Seems
to be running ( briskly walking ) fine now :

https://lists.nongnu.org/archive/html/qemu-discuss/2020-04/msg00078.html

If I see anything curious I will be sure to report.

Also I will rebuild QEMU without the debug and check the speed that I
 get. If any.



--
Dennis Clarke
RISC-V/SPARC/PPC/ARM/CISC
UNIX and Linux spoken
GreyBeard and suspenders optional




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