Re: [Qemu-devel] [PATCH 00/10] tb hash improvements

[Paolo Bonzini]

On 05/04/2016 07:30, Emilio G. Cota wrote:
> This patchset is derived from my ongoing work on MTTCG, but does
> not depend on it and brings improvements that we can already
> benefit from. It applies cleanly on the current master and
> is checkpatch-clean.
> 
> The key goal is to make the TB hash table faster, and while at it,
> scalable. Tested on two different host machines, the execution time
> improvement before and after this series, when booting a debian
> jessie arm image[*] with arm-softmmu, is:
> 
> - Intel Xeon E5-2690: 21.2% less time
> - Intel i7-4790K: 23.5% less time
> 
> This workload is particularly sensitive to TB hash performance.
> Other workloads not as sensitive might see a slight performance
> degradation with this patchset, since the hashing + lookup
> functions take now more instructions. In any case, no significant
> slowdowns should occur.
> 
> The commit logs are sometimes long because I have lots of numbers
> to share.
> 
> The only bits I'm not too comfortable with in this series are patches
> 2 and 5; I don't develop on Windows so I'm shooting in the dark there.
> 
> Please take a look and if possible, test on workloads you care about!

That's great stuff.  It will have to wait for 2.7, but it's really good.

Paolo