Re: [Qemu-devel] [PATCH for-1.5 0/9] Disable expensive QOM cast debugging for official releases

[Paolo Bonzini]

Il 10/05/2013 15:23, Andreas Färber ha scritto:
> Am 10.05.2013 15:08, schrieb Paolo Bonzini:
>> Il 10/05/2013 15:01, Anthony Liguori ha scritto:
>>> I'd prefer not to disable but instead focus on improving performance.
>>
>> For 1.5?  This is a regression in 1.5 due to more and more usage of
>> foo_env_on_cpu.
> 
> If CPUs were the only reason, we could simply change those inlines and
> ENV_GET_CPU() macro to use a C cast. No complicated interface scenarios
> requiring a dynamic cast are used for CPUs so far to my knowledge.

Almost nothing really requires a dynamic cast in QEMU.  Only interface
casts do, and there's just a couple of uses of interfaces.

And I wrote in the cover letter that what I want is really avoid the
need for "fast casts" in the hot paths.

Can you guys actually read the commit messages?

> Either way, it would be nice to see the call sites of those
> most-impacting dynamic casts! So far I held back my APIC RFC since I'm
> not sure how to reproducibly profile things.

It's interrupts (both sending and returning from them).

Paolo