On Wed, Feb 13, 2019 at 11:03:12AM +1100, Benjamin Herrenschmidt wrote: > On Tue, 2019-02-12 at 16:59 +1100, David Gibson wrote: > > On Mon, Jan 28, 2019 at 10:46:13AM +0100, Cédric Le Goater wrote: > > > From: Benjamin Herrenschmidt <b...@kernel.crashing.org> > > > > > > There's no point in going out of translation on an SMT OR with > > > mttcg since the backend won't do anything useful such as pausing, > > > it's only useful on traditional TCG to give time to other > > > processors. > > > > Is it actively harmful in the MTTCG case, or just pointless? > > I think it can hurt performance, I don't remember for sure :) > > > > Signed-off-by: Benjamin Herrenschmidt <b...@kernel.crashing.org> > > > Signed-off-by: Cédric Le Goater <c...@kaod.org> > > > --- > > > target/ppc/translate.c | 6 ++++-- > > > 1 file changed, 4 insertions(+), 2 deletions(-) > > > > > > diff --git a/target/ppc/translate.c b/target/ppc/translate.c > > > index e169c43643a1..7d40a1fbe6bd 100644 > > > --- a/target/ppc/translate.c > > > +++ b/target/ppc/translate.c > > > @@ -1580,7 +1580,7 @@ static void gen_pause(DisasContext *ctx) > > > tcg_temp_free_i32(t0); > > > > > > /* Stop translation, this gives other CPUs a chance to run */ > > > - gen_exception_nip(ctx, EXCP_HLT, ctx->base.pc_next); > > > + gen_exception_nip(ctx, EXCP_INTERRUPT, ctx->base.pc_next); > > > > I don't see how this change relates to the rest. > > Yeah not sure anymore :-)
Oh. That certainly doesn't make this easier to review.
So, all these target/ppc patches are only indirectly related to XIVE
pnv support. Cédric, can you split them out into their own series on
the next spin.
>
> > > }
> > > #endif /* defined(TARGET_PPC64) */
> > >
> > > @@ -1662,7 +1662,9 @@ static void gen_or(DisasContext *ctx)
> > > * than no-op, e.g., miso(rs=26), yield(27), mdoio(29),
> > > mdoom(30),
> > > * and all currently undefined.
> > > */
> > > - gen_pause(ctx);
> > > + if (!mttcg_enabled) {
> > > + gen_pause(ctx);
> > > + }
> > > #endif
> > > #endif
> > > }
>
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
signature.asc
Description: PGP signature
