Re: [RFC] Don't lookup full CPU state in the indirect branch fast path on AArch64 when running in user mode.

[Owen Anderson]

On Mon, Oct 19, 2020 at 11:22 AM Richard Henderson
<richard.henderson@linaro.org> wrote:
>
> (1) What qemu version are you looking at and,
> (2) Do you have --enable-tcg-debug enabled?

My use case is a large automated testing environment for large C++
binaries with heavy use of virtual dispatch.  The binaries are
generally not built at high optimization levels (-O0 or -O1), so it's
not very surprising to me that indirect branches are more dominant in
this as a workload

My use case is currently using QEMU 4.0, but we will be moving to QEMU
4.2 soon.  I do not have --enable-tcg-debug enabled.
e979972a6a1 does look promising, and like it might deliver increased
performance for our use case. It looks like the code in 4.0 is doing a
lot more work gathering the flags values from a variety of places.

--Owen