We weren't using cs_base in the hash calculations before. Since the arm front end moved a chunk of flags in a378206a20 (target/arm: Move mode specific TB flags to tb->cs_base) they comprise of an important part of the execution state.
Widen the tb_hash_func to include cs_base and expand to qemu_xxhash8() to accommodate it. My initial benchmark run on armhf shows very little difference in the runtime. Before: Time (mean ± σ): 24.440 s ± 2.885 s [User: 34.474 s, System: 2.028 s] Range (min … max): 21.663 s … 29.937 s 20 runs After: Time (mean ± σ): 24.348 s ± 2.717 s [User: 34.668 s, System: 1.859 s] Range (min … max): 21.830 s … 30.093 s 20 runs Signed-off-by: Alex Bennée <alex.ben...@linaro.org> --- accel/tcg/tb-hash.h | 5 +++-- include/qemu/xxhash.h | 21 +++++++++++++++------ accel/tcg/cpu-exec.c | 2 +- accel/tcg/tb-maint.c | 4 ++-- 4 files changed, 21 insertions(+), 11 deletions(-) diff --git a/accel/tcg/tb-hash.h b/accel/tcg/tb-hash.h index 1d19c69caa..8cbafb5494 100644 --- a/accel/tcg/tb-hash.h +++ b/accel/tcg/tb-hash.h @@ -62,9 +62,10 @@ static inline unsigned int tb_jmp_cache_hash_func(target_ulong pc) static inline uint32_t tb_hash_func(tb_page_addr_t phys_pc, target_ulong pc, - uint32_t flags, uint32_t cf_mask) + uint32_t flags, uint64_t flags2, uint32_t cf_mask) { - return qemu_xxhash6(phys_pc, pc, flags, cf_mask); + return qemu_xxhash8(phys_pc, pc, flags, + flags2 & 0xffff, flags2 >> 32, cf_mask); } #endif diff --git a/include/qemu/xxhash.h b/include/qemu/xxhash.h index c2dcccadbf..cd7054f07e 100644 --- a/include/qemu/xxhash.h +++ b/include/qemu/xxhash.h @@ -48,8 +48,8 @@ * xxhash32, customized for input variables that are not guaranteed to be * contiguous in memory. */ -static inline uint32_t -qemu_xxhash7(uint64_t ab, uint64_t cd, uint32_t e, uint32_t f, uint32_t g) +static inline uint32_t qemu_xxhash8(uint64_t ab, uint64_t cd, uint32_t e, + uint32_t f, uint32_t g, uint32_t h) { uint32_t v1 = QEMU_XXHASH_SEED + PRIME32_1 + PRIME32_2; uint32_t v2 = QEMU_XXHASH_SEED + PRIME32_2; @@ -89,6 +89,9 @@ qemu_xxhash7(uint64_t ab, uint64_t cd, uint32_t e, uint32_t f, uint32_t g) h32 += g * PRIME32_3; h32 = rol32(h32, 17) * PRIME32_4; + h32 += h * PRIME32_3; + h32 = rol32(h32, 17) * PRIME32_4; + h32 ^= h32 >> 15; h32 *= PRIME32_2; h32 ^= h32 >> 13; @@ -100,23 +103,29 @@ qemu_xxhash7(uint64_t ab, uint64_t cd, uint32_t e, uint32_t f, uint32_t g) static inline uint32_t qemu_xxhash2(uint64_t ab) { - return qemu_xxhash7(ab, 0, 0, 0, 0); + return qemu_xxhash8(ab, 0, 0, 0, 0, 0); } static inline uint32_t qemu_xxhash4(uint64_t ab, uint64_t cd) { - return qemu_xxhash7(ab, cd, 0, 0, 0); + return qemu_xxhash8(ab, cd, 0, 0, 0, 0); } static inline uint32_t qemu_xxhash5(uint64_t ab, uint64_t cd, uint32_t e) { - return qemu_xxhash7(ab, cd, e, 0, 0); + return qemu_xxhash8(ab, cd, e, 0, 0, 0); } static inline uint32_t qemu_xxhash6(uint64_t ab, uint64_t cd, uint32_t e, uint32_t f) { - return qemu_xxhash7(ab, cd, e, f, 0); + return qemu_xxhash8(ab, cd, e, f, 0, 0); +} + +static inline uint32_t qemu_xxhash7(uint64_t ab, uint64_t cd, uint32_t e, + uint32_t f, uint32_t g) +{ + return qemu_xxhash8(ab, cd, e, f, g, 0); } /* diff --git a/accel/tcg/cpu-exec.c b/accel/tcg/cpu-exec.c index 973da2a434..8d67198e56 100644 --- a/accel/tcg/cpu-exec.c +++ b/accel/tcg/cpu-exec.c @@ -233,7 +233,7 @@ static TranslationBlock *tb_htable_lookup(CPUState *cpu, target_ulong pc, } desc.page_addr0 = phys_pc; h = tb_hash_func(phys_pc, (cflags & CF_PCREL ? 0 : pc), - flags, cflags); + flags, cs_base, cflags); return qht_lookup_custom(&tb_ctx.htable, &desc, h, tb_lookup_cmp); } diff --git a/accel/tcg/tb-maint.c b/accel/tcg/tb-maint.c index 432a0cffdb..52d17815e4 100644 --- a/accel/tcg/tb-maint.c +++ b/accel/tcg/tb-maint.c @@ -887,7 +887,7 @@ static void do_tb_phys_invalidate(TranslationBlock *tb, bool rm_from_page_list) /* remove the TB from the hash list */ phys_pc = tb_page_addr0(tb); h = tb_hash_func(phys_pc, (orig_cflags & CF_PCREL ? 0 : tb->pc), - tb->flags, orig_cflags); + tb->flags, tb->cs_base, orig_cflags); if (!qht_remove(&tb_ctx.htable, tb, h)) { return; } @@ -968,7 +968,7 @@ TranslationBlock *tb_link_page(TranslationBlock *tb, tb_page_addr_t phys_pc, /* add in the hash table */ h = tb_hash_func(phys_pc, (tb->cflags & CF_PCREL ? 0 : tb->pc), - tb->flags, tb->cflags); + tb->flags, tb->cs_base, tb->cflags); qht_insert(&tb_ctx.htable, tb, h, &existing_tb); /* remove TB from the page(s) if we couldn't insert it */ -- 2.39.2