Re: [PATCH v3] target/riscv: Use env_archcpu for better performance

[Richard Henderson]

On 10/9/23 05:48, Richard W.M. Jones wrote:
> RISCV_CPU(cs) uses a checked cast.  When QOM cast debugging is enabled
> this adds about 5% total overhead when emulating RV64 on x86-64 host.
>
> Using a RISC-V guest with 16 vCPUs, 16 GB of guest RAM, virtio-blk
> disk.  The guest has a copy of the qemu source tree.  The test
> involves compiling the qemu source tree with 'make clean; time make -j16'.
>
> Before making this change the compile step took 449 & 447 seconds over
> two consecutive runs.
>
> After making this change: 428 & 421 seconds.
>
> The saving is over 5%.
>
> Thanks: Paolo Bonzini
> Thanks: Philippe Mathieu-Daudé
> Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
> ---
>   target/riscv/cpu_helper.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>


r~