Richard Henderson <r...@twiddle.net> writes:
> From: "Emilio G. Cota" <c...@braap.org>
>
> 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 <r...@twiddle.net>
> Signed-off-by: Emilio G. Cota <c...@braap.org>
> Message-Id: <1493263764-18657-11-git-send-email-c...@braap.org>
> Signed-off-by: Richard Henderson <r...@twiddle.net>
Reviewed-by: Alex Bennée <alex.ben...@linaro.org>
> ---
> 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
