From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:44361) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gtpaR-0000ir-4I for qemu-devel@nongnu.org; Wed, 13 Feb 2019 03:08:08 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gtpaQ-0006em-9n for qemu-devel@nongnu.org; Wed, 13 Feb 2019 03:08:07 -0500 Received: from 5.mo178.mail-out.ovh.net ([46.105.51.53]:50666) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1gtpaQ-0006cb-2e for qemu-devel@nongnu.org; Wed, 13 Feb 2019 03:08:06 -0500 Received: from player730.ha.ovh.net (unknown [10.109.146.132]) by mo178.mail-out.ovh.net (Postfix) with ESMTP id 656BD51CA3 for ; Wed, 13 Feb 2019 09:08:04 +0100 (CET) References: <20190128094625.4428-1-clg@kaod.org> <20190128094625.4428-8-clg@kaod.org> <20190212055900.GN1884@umbus.fritz.box> <56a5772ae88c5b5f65c969e2191a02d62cca5055.camel@kernel.crashing.org> <20190213045427.GK1884@umbus.fritz.box> From: =?UTF-8?Q?C=c3=a9dric_Le_Goater?= Message-ID: Date: Wed, 13 Feb 2019 09:07:59 +0100 MIME-Version: 1.0 In-Reply-To: <20190213045427.GK1884@umbus.fritz.box> Content-Type: text/plain; charset=windows-1252 Content-Language: en-US Content-Transfer-Encoding: quoted-printable Subject: Re: [Qemu-devel] [PATCH 07/19] target/ppc: Make special ORs match x86 pause and don't generate on mttcg List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: David Gibson , Benjamin Herrenschmidt Cc: qemu-ppc@nongnu.org, qemu-devel@nongnu.org On 2/13/19 5:54 AM, David Gibson wrote: > 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, C=E9dric Le Goater wrote: >>>> From: Benjamin Herrenschmidt >>>> >>>> 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 >>>> Signed-off-by: C=E9dric Le Goater >>>> --- >>>> 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); >>>> =20 >>>> /* 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 :-) >=20 > Oh. That certainly doesn't make this easier to review. >=20 > So, all these target/ppc patches are only indirectly related to XIVE > pnv support. C=E9dric, can you split them out into their own series on > the next spin. Sure. I will address your comments and resend them first. =20 Thanks, C. >=20 >> >>>> } >>>> #endif /* defined(TARGET_PPC64) */ >>>> =20 >>>> @@ -1662,7 +1662,9 @@ static void gen_or(DisasContext *ctx) >>>> * than no-op, e.g., miso(rs=3D26), yield(27), mdoio(29), m= doom(30), >>>> * and all currently undefined. >>>> */ >>>> - gen_pause(ctx); >>>> + if (!mttcg_enabled) { >>>> + gen_pause(ctx); >>>> + } >>>> #endif >>>> #endif >>>> } >> >=20