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

[Philippe Mathieu-Daudé]

On Fri, Jan 22, 2021 at 10:43 AM Thomas Huth <thuth@redhat.com> wrote:
> On 22/01/2021 10.22, 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.
> >
> > 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 0a645e54662..7aa52d306c6 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
> >     accelerators += 'CONFIG_TCG'
> >     config_host += { 'CONFIG_TCG': 'y' }
> >   endif
> >
>
> Reviewed-by: Thomas Huth <thuth@redhat.com>
>
> ... maybe you could also add some wording to the help text of the configure
> script? Or maybe we could simply rename the "--enable-tcg-interpreter"
> option into "--enable-tci" to avoid confusion with the normal TCG ?

I also thought about renaming as --enable-experimental-tci but then doubt that
would help, some users just want to enable everything :)