From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:35109) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1d49DP-0007xG-LR for qemu-devel@nongnu.org; Fri, 28 Apr 2017 12:57:56 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1d49DL-0000Fx-QM for qemu-devel@nongnu.org; Fri, 28 Apr 2017 12:57:55 -0400 Received: from mail-wm0-x22c.google.com ([2a00:1450:400c:c09::22c]:34824) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1d49DL-0000Fi-Gv for qemu-devel@nongnu.org; Fri, 28 Apr 2017 12:57:51 -0400 Received: by mail-wm0-x22c.google.com with SMTP id w64so47398965wma.0 for ; Fri, 28 Apr 2017 09:57:51 -0700 (PDT) References: <20170427120006.20564-1-rth@twiddle.net> <20170427120006.20564-13-rth@twiddle.net> From: Alex =?utf-8?Q?Benn=C3=A9e?= In-reply-to: <20170427120006.20564-13-rth@twiddle.net> Date: Fri, 28 Apr 2017 17:58:21 +0100 Message-ID: <87pofw79le.fsf@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [PATCH v5 12/19] target/i386: optimize indirect branches 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" > > Speed up indirect branches by jumping to the target if it is valid. > > Softmmu measurements (see later commit for user-mode numbers): > > Note: baseline (i.e. speedup == 1x) is QEMU v2.9.0. > > - SPECint06 (test set), x86_64-softmmu (Ubuntu 16.04 guest). Host: Intel i7-4790K @ 4.00GHz > > 2.4x +-+--------------------------------------------------------------------------------------------------------------+-+ > | | > | cross | > 2.2x +cross+jr..........................................................................+++...........................+-+ > | | | > | +++ | | > 2x +-+..............................................................................|..|............................+-+ > | | | | > | | | | > 1.8x +-+..............................................................................|####...........................+-+ > | |# |# | > | **** |# | > 1.6x +-+............................................................................*.|*.|#...........................+-+ > | * |* |# | > | * |* |# | > 1.4x +-+.......................................................................+++..*.|*.|#...........................+-+ > | ++++++ #### * |*++# +++ | > | +++ | | #++# *++* # +++ | | > 1.2x +-+......................###.....####....+++............|..|...........****..#.*..*..#....####...|.###.....####..+-+ > | +++ **** # **** # #### ***### *++* # * * # #++# ****|# +++#++# | > | ****### +++ *++* # *++* # ++# # #### *|* |# +++ * * # * * # *** # *| *|# **** # | > 1x +-++-*++*++#++***###++*++*+#++*+-*++#+****++#++***++#+-*+*++#-+****##++*++*-+#+*++*-+#++*+*++#++*-+*+#++*++*++#-++-+ > | * * # * * # * * # * * # * * # * * # *|* |# *++* # * * # * * # * * # * * # * * # | > | * * # * * # * * # * * # * * # * * # *+*++# * * # * * # * * # * * # * * # * * # | > 0.8x +-+--****###--***###--****##--****###-****###--***###--***###--****##--****###-****###--***###--****##--****###--+-+ > astar bzip2 gcc gobmk h264ref hmmlibquantum mcf omnetpperlbench sjengxalancbmk hmean > png: http://imgur.com/DU36YFU > > NB. 'cross' represents the previous commit. > > Reviewed-by: Richard Henderson > Signed-off-by: Emilio G. Cota > Message-Id: <1493263764-18657-11-git-send-email-cota@braap.org> > Signed-off-by: Richard Henderson Reviewed-by: Alex Bennée > --- > target/i386/translate.c | 14 ++++++++------ > 1 file changed, 8 insertions(+), 6 deletions(-) > > diff --git a/target/i386/translate.c b/target/i386/translate.c > index ea113fe..674ec96 100644 > --- a/target/i386/translate.c > +++ b/target/i386/translate.c > @@ -4996,7 +4996,7 @@ static target_ulong disas_insn(CPUX86State *env, DisasContext *s, > gen_push_v(s, cpu_T1); > gen_op_jmp_v(cpu_T0); > gen_bnd_jmp(s); > - gen_eob(s); > + gen_jr(s, cpu_T0); > break; > case 3: /* lcall Ev */ > gen_op_ld_v(s, ot, cpu_T1, cpu_A0); > @@ -5014,7 +5014,8 @@ static target_ulong disas_insn(CPUX86State *env, DisasContext *s, > tcg_const_i32(dflag - 1), > tcg_const_i32(s->pc - s->cs_base)); > } > - gen_eob(s); > + tcg_gen_ld_tl(cpu_tmp4, cpu_env, offsetof(CPUX86State, eip)); > + gen_jr(s, cpu_tmp4); > break; > case 4: /* jmp Ev */ > if (dflag == MO_16) { > @@ -5022,7 +5023,7 @@ static target_ulong disas_insn(CPUX86State *env, DisasContext *s, > } > gen_op_jmp_v(cpu_T0); > gen_bnd_jmp(s); > - gen_eob(s); > + gen_jr(s, cpu_T0); > break; > case 5: /* ljmp Ev */ > gen_op_ld_v(s, ot, cpu_T1, cpu_A0); > @@ -5037,7 +5038,8 @@ static target_ulong disas_insn(CPUX86State *env, DisasContext *s, > gen_op_movl_seg_T0_vm(R_CS); > gen_op_jmp_v(cpu_T1); > } > - gen_eob(s); > + tcg_gen_ld_tl(cpu_tmp4, cpu_env, offsetof(CPUX86State, eip)); > + gen_jr(s, cpu_tmp4); > break; > case 6: /* push Ev */ > gen_push_v(s, cpu_T0); > @@ -6417,7 +6419,7 @@ static target_ulong disas_insn(CPUX86State *env, DisasContext *s, > /* Note that gen_pop_T0 uses a zero-extending load. */ > gen_op_jmp_v(cpu_T0); > gen_bnd_jmp(s); > - gen_eob(s); > + gen_jr(s, cpu_T0); > break; > case 0xc3: /* ret */ > ot = gen_pop_T0(s); > @@ -6425,7 +6427,7 @@ static target_ulong disas_insn(CPUX86State *env, DisasContext *s, > /* Note that gen_pop_T0 uses a zero-extending load. */ > gen_op_jmp_v(cpu_T0); > gen_bnd_jmp(s); > - gen_eob(s); > + gen_jr(s, cpu_T0); > break; > case 0xca: /* lret im */ > val = cpu_ldsw_code(env, s->pc); -- Alex Bennée