Re: [PATCH v3 2/4] meson: Warn when TCI is selected but TCG backend is available

[Daniel P . Berrangé]

On Fri, Jan 22, 2021 at 02:30:02PM +0100, Philippe Mathieu-Daudé wrote:
> Some new users get confused with 'TCG' and 'TCI', and enable TCI
> support expecting to enable TCG.
> 
> Emit a warning when native TCG backend is available on the
> host architecture, mentioning this is a suboptimal configuration.
> 
> Reviewed-by: Stefan Weil <sw@weilnetz.de>
> Reviewed-by: Thomas Huth <thuth@redhat.com>
> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
> ---
>  meson.build | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/meson.build b/meson.build
> index d5b76150e49..d3df5fa3516 100644
> --- a/meson.build
> +++ b/meson.build
> @@ -234,6 +234,9 @@
>        error('Unsupported CPU @0@, try --enable-tcg-interpreter'.format(cpu))
>      endif
>    endif
> +  if 'CONFIG_TCG_INTERPRETER' in config_host and cpu in supported_cpus
> +    warning('Experimental TCI requested while native TCG is available on 
> @0@, suboptimal performance expected'.format(cpu))
> +  endif

warning('Use of the TCG interpretor is not recommended on this host
         architecture. There is a native TCG execution backend available
         which provides substantially better performance and reliability. 
         It is strongly recommended to remove the --enable-tcg-interpreter 
         configuration option on this architecture to use the native
         backend.')


Regards,
Daniel
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