Re: [Qemu-devel] [Qemu-ppc] [RFC PATCH 0/6] target/ppc: convert VMX instructions to use TCG vector operations

[Richard Henderson]

On 12/11/18 1:35 PM, Mark Cave-Ayland wrote:
> Looking at your profiles above, the primary hotspot appears to be
> helper_lookup_tb_ptr(). However as someone quite new to the TCG parts of 
> QEMU, I
> couldn't tell you whether or not this is to be expected.
> 
> Perhaps a question for Richard: what could we consider to be a "normal" 
> backend when
> looking at profiles in terms of recommended features to implement, and to get 
> an idea
> of what a typical profile should look like?
> 
> It would be interesting to compare with a similar workload profile on e.g. 
> ARM to see
> if there is anything obvious that stands out for PPC.

For Alpha, which has relatively sane tlb management, the top entry in the
profile is helper_lookup_tb_ptr at about 8%.  Otherwise, somewhere in the top 2
or 3 functions will be helper_le_ldq_mmu at about 2%.

That's probably a best-case scenario.


r~