Re: [Qemu-devel] Update on TCG Multithreading

[Dr. David Alan Gilbert]

* Mark Burton (address@hidden) wrote:
> 
> All - first a huge thanks for those who have contributed, and those who have 
> expressed an interest in helping out.
> 
> One issue I???d like to see more opinions on is the question of a cache per 
> core, or a shared cache.
> I have heard anecdotal evidence that a shared cache gives a major performance 
> benefit???.
> Does anybody have anything more concrete?
> (of course we will get numbers in the end if we implement the hybrid scheme 
> as suggested in the wiki - but I???d still appreciate any feedback).
> 
> Our next plan is to start putting an implementation plan together. Probably 
> quite sketchy at this point, and we hope to start coding shortly.

I'd expect a shared one to be able to take advantage
of code that's translated by one core and then used on
another.
On the other hand with one per core you can perform updates
on the caches with a lot less locking; however you've still
got to be able to do invalidates across all the caches if any
core does the write, and that could also get tricky.

Dave

> 
> 
> Cheers
> 
> Mark.
> 
> 
> 
> 
> 
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>       mark.burton
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--
Dr. David Alan Gilbert / address@hidden / Manchester, UK