Re: [Qemu-devel] [RFC 38/38] Revert "target-i386: yield to another VCPU on PAUSE"

[Paolo Bonzini]

On 23/08/2015 17:24, Emilio G. Cota wrote:
> This reverts commit 81f3053b77f7d3a4d9100c425cd8cec99ee7a3d4.
> 
> The interrupt raised by the change in the commit above
> kills performance when running many idling VCPUs. For example,
> on my 64-core host when running a workload where cores are
> idling often (e.g. blackscholes), performance drops significantly
> because threads are most of the time just exiting the CPU loop,
> thereby causing great contention on the BQL.
> 
> Fix it by reverting to the old behaviour by which no
> interrupt is raised, which shouldn't be an issue given that
> we have now one thread per VCPU.
> 
> Signed-off-by: Emilio G. Cota <address@hidden>

Agreed, this is not necessary anymore!

Paolo