Re: [Qemu-devel] Re: sparc64 lazy conditional codes evaluation

[Mark Cave-Ayland <mark.cave-ayland@siriusit.co.uk>]

Blue Swirl wrote:

> Thanks a lot, with this patch my tests passed! I applied the combined patch.

Yes, I definitely see an improvement with this patch - at least my 
Debian lenny SPARC boot cd doesn't randomly kernel panic any more. It 
looks as if it now just can't find /init which could just be due to an 
incorrect device mapping somewhere.

> I also did a bit of refactoring to get the original Sparc64 issue fixed.

However, one thing I did notice is that this does introduce a noticeable 
performance penalty. With OpenBIOS SVN head I see the following:

With commit 72139e83a98eba2bfed2dbc2db2818fb19e47ca0 (just before the 
changes):

[   59.225406] Failed to execute /init
[   59.304088] Kernel panic - not syncing: No init found.  Try passing 
init= option to kernel.
[   59.450313] Press Stop-A (L1-A) to return to the boot prom

With commit 5a834bb47c373e887de5210b7ceae96e1ef413f7 (just after the 
changes):

[   70.384466] Failed to execute /init
[   70.474804] Kernel panic - not syncing: No init found.  Try passing 
init= option to kernel.


So while it's technically correct, it seems to have added ~15% overhead 
to the emulation :(


ATB,

Mark.

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Mark Cave-Ayland - Senior Technical Architect
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