Re: Sudden slowdown of ARM emulation in master

[Peter Maydell]

On Wed, 26 Feb 2020 at 09:19, Igor Mammedov <address@hidden> wrote:
>
> On Wed, 26 Feb 2020 00:07:55 +0100
> Niek Linnenbank <address@hidden> wrote:
>
> > Hello Igor and Paolo,
>
> does following hack solves issue?
>
> diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
> index a08ab11f65..ab2448c5aa 100644
> --- a/accel/tcg/translate-all.c
> +++ b/accel/tcg/translate-all.c
> @@ -944,7 +944,7 @@ static inline size_t size_code_gen_buffer(size_t tb_size)
>          /* ??? If we relax the requirement that CONFIG_USER_ONLY use the
>             static buffer, we could size this on RESERVED_VA, on the text
>             segment size of the executable, or continue to use the default.  
> */
> -        tb_size = (unsigned long)(ram_size / 4);
> +        tb_size = MAX_CODE_GEN_BUFFER_SIZE;
>  #endif
>      }
>      if (tb_size < MIN_CODE_GEN_BUFFER_SIZE) {

Cc'ing Richard to ask: does it still make sense for TCG
to pick a codegen buffer size based on the guest RAM size?
(We should fix the regression anyway, but it surprised me
slightly to find a config detail of the guest machine being
used here.)

thanks
-- PMM