Re: [Qemu-devel] [RFC v2 08/11] tcg: add options for enabling MTTCG

[KONRAD Frederic]

Le 12/04/2016 14:42, Sergey Fedorov a écrit :
> On 12/04/16 14:59, Peter Maydell wrote:
> > On 12 April 2016 at 12:48, Alex Bennée <address@hidden> wrote:
> > > Sergey Fedorov <address@hidden> writes:
> > > > Maybe we'd better use existing qemu accelerator framework and introduce
> > > > "-machine accel=mttcg" option?
> > > My worry would be breaking existing code which assumes kvm | tcg. We
> > > will want to enable mttcg by default for combos that work without having
> > > to tweak tooling that already uses the -machine options.
> > Comments from the peanut gallery:
> >   * We definitely want to just default to MTTCG where it works:
> > users shouldn't have to add new command line switches to get the
> > better performance etc, because in practice that won't happen
> >   * Anything that adds a new command line option at all has to
> > be supported practically forever, so options that are only
> > useful for a transitional period are worth thinking twice about
>
> Yes, but users may like to have an option to disable MTTCG for some
> reason. I'm also concerned about icount mode: not sure how to account
> virtual time when all vCPUs run in parallel.

Hi,

I'm thinking the same, we don't have a solution for icount yet.
The reverse execution support is probably badly broken as well.

Fred

> Kind regards,
> Sergey