Instead of unconditionally exiting to the exec loop, add a helper to
check whether the target TB is valid. As long as the hit rate in
tb_jmp_cache remains high, this improves performance.
Measurements:
- specINT 2006 (test set), x86_64-softmmu. Host: Intel i7-4790K @ 4.00GHz
Y axis: Speedup over 95b31d70
1.3x+-+-------------------------------------------------------------+-+
| cross $$ |
1.25x+-+.............................................................+-+
| |
1.2x+-+.............................................................+-+
| : |
| : |
1.15x+-+.............................................................+-+
| $$$$ $$$$ +++ : |
1.1x+-+.........$..$.$..$...........................................+-+
| $ $ $ $ $$$ $$$$ |
1.05x+-+.........$..$.$..$.....................$.$.$$$$......$..$....+-+
| $ $ $ $ +++ +++ +++ $+$ $++$ +++ $: $ $$$$ |
| +++ $ $ $ $ +++ $$$ : : $ $ $ $ $$$$ $: $ $++$ |
1x+-$$$$G$$$$_$EM$_$ro$s$$$..$.$.......$$$..$.$.$..$.$..$.$..$.$..$-+
| $++$ $ :$ $ $ $ $ $ $ $ $ : $+$ $ $ $ $ $++$ $: $ $ $ |
0.95x+-$..$.$..$.$..$.$..$.$.$..$.$..$$$..$.$..$.$.$..$.$..$.$..$.$..$-+
| $ $ $ $ $ $ $ $ $ $ $ $ $:$ $ $ $ $ $ $ $ $ $ $ $ $ |
0.9x+-$$$$-$$$$-$$$$-$$$$-$$$--$$$--$$$--$$$--$$$-$$$$-$$$$-$$$$-$$$$-+
astarbzip2gcc gobmh264rehmlibquantumcfomneperlbensjxalancbhmean
png: http://imgur.com/cwRnmCi
That is, a hmean gain of 2.6%.
- specINT 2006 (train set), x86_64-softmmu. Host: Intel i7-4790K @ 4.00GHz
Y axis: Speedup over 95b31d70
1.25x+-+-------------------------------------------------------------+-+
| cross $$ |
| |
1.2x+-+.............................................................+-+
| : +++ |
1.15x+-+.............................................................+-+
| : $$$ $$$$ $$$$ |
| $$$$ +++ $:$ $++$ +++ $: $ |
1.1x+-+.........$..$.$$$$.....................$.$.$..$......$..$....+-+
| +++ $++$ $++$ +++ : $ $ $ $ : $++$ +++ |
1.05x+-+....$$$$.$..$.$..$......$$$............$.$.$..$.$$$$.$..$.$$$$-+
| $++$ $ $ $ $ $$$ $:$ $ $ $ $ $ :$ $ $ $ $ |
| $ $ $ $ $ $ $:$ $+$ +++ +++ $ $ $ $ $ :$ $ $ $ $ |
1x+-$$$$G$AP$_$EM$_$ro$s$i$li$e$..$$$.......$.$.$..$.$..$.$..$.$..$-+
| $++$ $ $ $ $ $ $ $+$ $ $ $:$ $$$ $ $ $ $ $ $ $ $ $ $ |
0.95x+-$..$.$..$.$..$.$..$.$.$..$.$..$.$..$.$..$.$.$..$.$..$.$..$.$..$-+
| $ $ $ $ $ $ $ $ $ $ $ $ $ $ $+$ $ $ $ $ $ $ $ $ $ $ |
| $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ $ |
0.9x+-$$$$-$$$$-$$$$-$$$$-$$$--$$$--$$$--$$$--$$$-$$$$-$$$$-$$$$-$$$$-+
astarbzip2gcc gobmh264rehmlibquantumcfomneperlbensjxalancbhmean
png: http://imgur.com/0CbG7dD
This is the larger "train" set. We get a hmean improvement of 6.1%.
Signed-off-by: Emilio G. Cota <c...@braap.org>
---
target/i386/helper.h | 2 ++
target/i386/misc_helper.c | 5 +++++
target/i386/translate.c | 14 +++++++++++++-
3 files changed, 20 insertions(+), 1 deletion(-)
diff --git a/target/i386/helper.h b/target/i386/helper.h
index 6fb8fb9..dceb343 100644
--- a/target/i386/helper.h
+++ b/target/i386/helper.h
@@ -1,6 +1,8 @@
DEF_HELPER_FLAGS_4(cc_compute_all, TCG_CALL_NO_RWG_SE, tl, tl, tl, tl, int)
DEF_HELPER_FLAGS_4(cc_compute_c, TCG_CALL_NO_RWG_SE, tl, tl, tl, tl, int)
+DEF_HELPER_2(cross_page_check, i32, env, tl)
+
DEF_HELPER_3(write_eflags, void, env, tl, i32)
DEF_HELPER_1(read_eflags, tl, env)
DEF_HELPER_2(divb_AL, void, env, tl)
diff --git a/target/i386/misc_helper.c b/target/i386/misc_helper.c
index ca2ea09..a41daed 100644
--- a/target/i386/misc_helper.c
+++ b/target/i386/misc_helper.c
@@ -637,3 +637,8 @@ void helper_wrpkru(CPUX86State *env, uint32_t ecx, uint64_t
val)
env->pkru = val;
tlb_flush(cs);
}
+
+uint32_t helper_cross_page_check(CPUX86State *env, target_ulong vaddr)
+{
+ return !!tb_from_jmp_cache(env, vaddr);
+}
diff --git a/target/i386/translate.c b/target/i386/translate.c
index 1d1372f..ffc8ccc 100644
--- a/target/i386/translate.c
+++ b/target/i386/translate.c
@@ -2153,7 +2153,19 @@ 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 */
+ TCGv vaddr = tcg_const_tl(eip);
+ TCGv_i32 valid = tcg_temp_new_i32();
+ TCGLabel *label = gen_new_label();
+
+ gen_helper_cross_page_check(valid, cpu_env, vaddr);
+ tcg_temp_free(vaddr);
+ tcg_gen_brcondi_i32(TCG_COND_EQ, valid, 0, label);
+ tcg_temp_free_i32(valid);
+ tcg_gen_goto_tb(tb_num);
+ gen_jmp_im(eip);
+ tcg_gen_exit_tb((uintptr_t)s->tb + tb_num);
+ gen_set_label(label);
gen_jmp_im(eip);
gen_eob(s);
}
--
2.7.4
