| Message ID | 20190219233421.388-4-richard.henderson@linaro.org |
|---|---|
| State | New |
| Headers | show |
| Series | target/arm: Reduce overhead of cpu_get_tb_cpu_state | expand |
Richard Henderson <richard.henderson@linaro.org> writes: > This is the payoff. > > From perf record -g data of ubuntu 18 boot and shutdown: > > BEFORE: > > - 23.02% 2.82% qemu-system-aar [.] helper_lookup_tb_ptr > - 20.22% helper_lookup_tb_ptr > + 10.05% tb_htable_lookup > - 9.13% cpu_get_tb_cpu_state > 3.20% aa64_va_parameters_both > 0.55% fp_exception_el > > - 11.66% 4.74% qemu-system-aar [.] cpu_get_tb_cpu_state > - 6.96% cpu_get_tb_cpu_state > 3.63% aa64_va_parameters_both > 0.60% fp_exception_el > 0.53% sve_exception_el > > AFTER: > > - 16.40% 3.40% qemu-system-aar [.] helper_lookup_tb_ptr > - 13.03% helper_lookup_tb_ptr > + 11.19% tb_htable_lookup > 0.55% cpu_get_tb_cpu_state > > 0.98% 0.71% qemu-system-aar [.] cpu_get_tb_cpu_state > > 0.87% 0.24% qemu-system-aar [.] rebuild_hflags_a64 > > Before, helper_lookup_tb_ptr is the second hottest function in the > application, consuming almost a quarter of the runtime. Within the > entire execution, cpu_get_tb_cpu_state consumes about 12%. > > After, helper_lookup_tb_ptr has dropped to the fourth hottest function, > with consumption dropping to a sixth of the runtime. Within the > entire execution, cpu_get_tb_cpu_state has dropped below 1%, and the > supporting function to rebuild hflags also consumes about 1%. > > Assertions are retained for --enable-debug-tcg. > > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Tested-by: Alex Bennée <alex.bennee@linaro.org> > --- > v2: Retain asserts for future debugging. > --- > target/arm/helper.c | 20 +++++++++++++++----- > 1 file changed, 15 insertions(+), 5 deletions(-) > > diff --git a/target/arm/helper.c b/target/arm/helper.c > index 909535a3e3..990a87876f 100644 > --- a/target/arm/helper.c > +++ b/target/arm/helper.c > @@ -14034,19 +14034,29 @@ void HELPER(rebuild_hflags_a64)(CPUARMState *env, uint32_t el) > void cpu_get_tb_cpu_state(CPUARMState *env, target_ulong *pc, > target_ulong *cs_base, uint32_t *pflags) > { > - int current_el = arm_current_el(env); > - uint32_t flags; > + uint32_t flags = env->hflags; > uint32_t pstate_for_ss; > > +#ifdef CONFIG_DEBUG_TCG > + { > + int el = arm_current_el(env); > + uint32_t check_flags; > + if (is_a64(env)) { > + check_flags = rebuild_hflags_a64(env, el); > + } else { > + check_flags = rebuild_hflags_a32(env, el); > + } > + g_assert_cmphex(flags, ==, check_flags); > + } > +#endif > + > *cs_base = 0; > - if (is_a64(env)) { > + if (FIELD_EX32(flags, TBFLAG_ANY, AARCH64_STATE)) { > *pc = env->pc; > - flags = rebuild_hflags_a64(env, current_el); > flags = FIELD_DP32(flags, TBFLAG_A64, BTYPE, env->btype); > pstate_for_ss = env->pstate; > } else { > *pc = env->regs[15]; > - flags = rebuild_hflags_a32(env, current_el); > flags = FIELD_DP32(flags, TBFLAG_A32, THUMB, env->thumb); > flags = FIELD_DP32(flags, TBFLAG_A32, CONDEXEC, env->condexec_bits); > pstate_for_ss = env->uncached_cpsr; -- Alex Bennée
diff --git a/target/arm/helper.c b/target/arm/helper.c index 909535a3e3..990a87876f 100644 --- a/target/arm/helper.c +++ b/target/arm/helper.c @@ -14034,19 +14034,29 @@ void HELPER(rebuild_hflags_a64)(CPUARMState *env, uint32_t el) void cpu_get_tb_cpu_state(CPUARMState *env, target_ulong *pc, target_ulong *cs_base, uint32_t *pflags) { - int current_el = arm_current_el(env); - uint32_t flags; + uint32_t flags = env->hflags; uint32_t pstate_for_ss; +#ifdef CONFIG_DEBUG_TCG + { + int el = arm_current_el(env); + uint32_t check_flags; + if (is_a64(env)) { + check_flags = rebuild_hflags_a64(env, el); + } else { + check_flags = rebuild_hflags_a32(env, el); + } + g_assert_cmphex(flags, ==, check_flags); + } +#endif + *cs_base = 0; - if (is_a64(env)) { + if (FIELD_EX32(flags, TBFLAG_ANY, AARCH64_STATE)) { *pc = env->pc; - flags = rebuild_hflags_a64(env, current_el); flags = FIELD_DP32(flags, TBFLAG_A64, BTYPE, env->btype); pstate_for_ss = env->pstate; } else { *pc = env->regs[15]; - flags = rebuild_hflags_a32(env, current_el); flags = FIELD_DP32(flags, TBFLAG_A32, THUMB, env->thumb); flags = FIELD_DP32(flags, TBFLAG_A32, CONDEXEC, env->condexec_bits); pstate_for_ss = env->uncached_cpsr;
This is the payoff. From perf record -g data of ubuntu 18 boot and shutdown: BEFORE: - 23.02% 2.82% qemu-system-aar [.] helper_lookup_tb_ptr - 20.22% helper_lookup_tb_ptr + 10.05% tb_htable_lookup - 9.13% cpu_get_tb_cpu_state 3.20% aa64_va_parameters_both 0.55% fp_exception_el - 11.66% 4.74% qemu-system-aar [.] cpu_get_tb_cpu_state - 6.96% cpu_get_tb_cpu_state 3.63% aa64_va_parameters_both 0.60% fp_exception_el 0.53% sve_exception_el AFTER: - 16.40% 3.40% qemu-system-aar [.] helper_lookup_tb_ptr - 13.03% helper_lookup_tb_ptr + 11.19% tb_htable_lookup 0.55% cpu_get_tb_cpu_state 0.98% 0.71% qemu-system-aar [.] cpu_get_tb_cpu_state 0.87% 0.24% qemu-system-aar [.] rebuild_hflags_a64 Before, helper_lookup_tb_ptr is the second hottest function in the application, consuming almost a quarter of the runtime. Within the entire execution, cpu_get_tb_cpu_state consumes about 12%. After, helper_lookup_tb_ptr has dropped to the fourth hottest function, with consumption dropping to a sixth of the runtime. Within the entire execution, cpu_get_tb_cpu_state has dropped below 1%, and the supporting function to rebuild hflags also consumes about 1%. Assertions are retained for --enable-debug-tcg. Signed-off-by: Richard Henderson <richard.henderson@linaro.org> --- v2: Retain asserts for future debugging. --- target/arm/helper.c | 20 +++++++++++++++----- 1 file changed, 15 insertions(+), 5 deletions(-)