From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:34702) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d49C2-0006l8-Hv for qemu-devel@nongnu.org; Fri, 28 Apr 2017 12:56:31 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1d49Bz-0008CW-DY for qemu-devel@nongnu.org; Fri, 28 Apr 2017 12:56:30 -0400 Received: from mail-wm0-x233.google.com ([2a00:1450:400c:c09::233]:36645) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1d49Bz-0008CK-6L for qemu-devel@nongnu.org; Fri, 28 Apr 2017 12:56:27 -0400 Received: by mail-wm0-x233.google.com with SMTP id u65so47331577wmu.1 for ; Fri, 28 Apr 2017 09:56:26 -0700 (PDT) References: <20170427120006.20564-1-rth@twiddle.net> <20170427120006.20564-12-rth@twiddle.net> From: Alex =?utf-8?Q?Benn=C3=A9e?= In-reply-to: <20170427120006.20564-12-rth@twiddle.net> Date: Fri, 28 Apr 2017 17:56:57 +0100 Message-ID: <87r30c79nq.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [PATCH v5 11/19] target/i386: optimize cross-page direct jumps in softmmu List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Richard Henderson Cc: qemu-devel@nongnu.org, cota@braap.org Richard Henderson writes: > From: "Emilio G. Cota" > > Instead of unconditionally exiting to the exec loop, use the > gen_jr helper to jump to the target if it is valid. > > Perf impact: see next commit's log. > > Reviewed-by: Richard Henderson > Signed-off-by: Emilio G. Cota > Message-Id: <1493263764-18657-10-git-send-email-cota@braap.org> > Signed-off-by: Richard Henderson > --- > target/i386/translate.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/target/i386/translate.c b/target/i386/translate.c > index f0e48dc..ea113fe 100644 > --- a/target/i386/translate.c > +++ b/target/i386/translate.c > @@ -2154,9 +2154,9 @@ static inline void gen_goto_tb(DisasContext *s, int tb_num, target_ulong eip) > gen_jmp_im(eip); > tcg_gen_exit_tb((uintptr_t)s->tb + tb_num); > } else { > - /* jump to another page: currently not optimized */ > + /* jump to another page */ > gen_jmp_im(eip); > - gen_eob(s); > + gen_jr(s, cpu_tmp0); I had to look up what was going on with cpu_tmp0 there. Is there a particular reason i386 has these global temps with implied setting rules? It does seem somewhat hacky. Given cmp_tmp0 seems to be a heavily used across i386 I guess it keeps to the style of the translator :-/ > } > } -- Alex Bennée