Re: [Qemu-devel] Update on TCG Multithreading

[Alexander Graf <agraf@suse.de>]

On 01.12.14 22:00, Lluís Vilanova wrote:
> Mark Burton writes:
> 
>> 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).
> 
> I think it makes sense to have a per-core pointer to a qom TCGCacheClass. That
> can then have its own methods for working with updates, making it much simpler
> to work with different implementations, like completely avoiding locks (per-cpu
> cache) or a hybrid approach like the one described in the wiki.

I don't think you want to have indirect function calls in the fast path ;).


Alex