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| author | Emilio G. Cota <cota@braap.org> | 2017-04-26 23:29:23 -0400 |
|---|---|---|
| committer | Richard Henderson <rth@twiddle.net> | 2017-06-05 09:25:42 -0700 |
| commit | b4aa297781ceddef79deb0e99da7817551fa89f8 (patch) | |
| tree | 765a99ef2be2f7bb646fe6972e5b671c232c8bc0 /target/i386 | |
| parent | fe62089563ffc6a42f16ff28a6b6be34d2697766 (diff) | |
| download | qemu-b4aa297781ceddef79deb0e99da7817551fa89f8.zip qemu-b4aa297781ceddef79deb0e99da7817551fa89f8.tar.gz qemu-b4aa297781ceddef79deb0e99da7817551fa89f8.tar.bz2 | |
target/i386: optimize indirect branches
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 +-+--------------------------------------------------------------------------------------------------------------+-+
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| cross |
2.2x +cross+jr..........................................................................+++...........................+-+
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| +++ | |
2x +-+..............................................................................|..|............................+-+
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1.8x +-+..............................................................................|####...........................+-+
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| **** |# |
1.6x +-+............................................................................*.|*.|#...........................+-+
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| * |* |# |
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: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Emilio G. Cota <cota@braap.org>
Message-Id: <1493263764-18657-11-git-send-email-cota@braap.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
Diffstat (limited to 'target/i386')
| -rw-r--r-- | target/i386/translate.c | 14 |
1 files 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); |