| Message ID | 20190820210720.18976-18-richard.henderson@linaro.org (mailing list archive) |
|---|---|
| State | New, archived |
| 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. > > Tested-by: Alex Bennée <alex.bennee@linaro.org> Hmm something must have been missed for M-profile because: make run-tcg-tests-arm-softmmu V=1 Leads to: timeout 15 /home/alex/lsrc/qemu.git/builds/all.debug/arm-softmmu/qemu-system-arm -monitor none -display none -chardev file,path=test-armv6m-undef.out,id=output -semihosting -M microbit -kernel test-armv6m-undef qemu: fatal: Lockup: can't escalate 3 to HardFault (current priority -1) R00=00000000 R01=00000000 R02=00000000 R03=00000000 R04=00000000 R05=00000000 R06=00000000 R07=00000000 R08=00000000 R09=00000000 R10=00000000 R11=00000000 R12=00000000 R13=20003fe0 R14=fffffff9 R15=000000c0 XPSR=41000003 -Z-- T handler FPSCR: 00000000 timeout: the monitored command dumped core But annoyingly not shown up by the debug-tcg verification. The commit before works fine. > Reviewed-by: Alex Bennée <alex.bennee@linaro.org> > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> > --- > v2: Retain asserts for future debugging. > --- > target/arm/helper.c | 9 ++++++--- > 1 file changed, 6 insertions(+), 3 deletions(-) > > diff --git a/target/arm/helper.c b/target/arm/helper.c > index d1bf71a260..5e4f996882 100644 > --- a/target/arm/helper.c > +++ b/target/arm/helper.c > @@ -11211,12 +11211,15 @@ void HELPER(rebuild_hflags_a64)(CPUARMState *env, int el) > void cpu_get_tb_cpu_state(CPUARMState *env, target_ulong *pc, > target_ulong *cs_base, uint32_t *pflags) > { > - uint32_t flags, pstate_for_ss; > + uint32_t flags = env->hflags; > + uint32_t pstate_for_ss; > > *cs_base = 0; > - flags = rebuild_hflags_internal(env); > +#ifdef CONFIG_TCG_DEBUG > + assert(flags == rebuild_hflags_internal(env)); > +#endif > > - if (is_a64(env)) { > + if (FIELD_EX32(flags, TBFLAG_ANY, AARCH64_STATE)) { > *pc = env->pc; > if (cpu_isar_feature(aa64_bti, env_archcpu(env))) { > flags = FIELD_DP32(flags, TBFLAG_A64, BTYPE, env->btype); -- Alex Bennée
On Thu, Sep 5, 2019 at 5:24 PM Alex Bennée <alex.bennee@linaro.org> wrote: > > > 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. > > > > Tested-by: Alex Bennée <alex.bennee@linaro.org> > > Hmm something must have been missed for M-profile because: > > make run-tcg-tests-arm-softmmu V=1 > > Leads to: > > timeout 15 /home/alex/lsrc/qemu.git/builds/all.debug/arm-softmmu/qemu-system-arm -monitor none -display none -chardev file,path=test-armv6m-undef.out,id=output -semihosting -M microbit -kernel test-armv6m-undef > qemu: fatal: Lockup: can't escalate 3 to HardFault (current priority -1) > > R00=00000000 R01=00000000 R02=00000000 R03=00000000 > R04=00000000 R05=00000000 R06=00000000 R07=00000000 > R08=00000000 R09=00000000 R10=00000000 R11=00000000 > R12=00000000 R13=20003fe0 R14=fffffff9 R15=000000c0 > XPSR=41000003 -Z-- T handler > FPSCR: 00000000 > timeout: the monitored command dumped core > > But annoyingly not shown up by the debug-tcg verification. The commit > before works fine. There's a typo in the patch: that should not be CONFIG_TCG_DEBUG but CONFIG_DEBUG_TCG. With this you should see the assert fire. I let Richard know that there's an issue with the handling of CPSR E flag (BE_DATA in hflags). I don't know if that applies to your test. Thanks, Laurent > > Reviewed-by: Alex Bennée <alex.bennee@linaro.org> > > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> > > --- > > v2: Retain asserts for future debugging. > > --- > > target/arm/helper.c | 9 ++++++--- > > 1 file changed, 6 insertions(+), 3 deletions(-) > > > > diff --git a/target/arm/helper.c b/target/arm/helper.c > > index d1bf71a260..5e4f996882 100644 > > --- a/target/arm/helper.c > > +++ b/target/arm/helper.c > > @@ -11211,12 +11211,15 @@ void HELPER(rebuild_hflags_a64)(CPUARMState *env, int el) > > void cpu_get_tb_cpu_state(CPUARMState *env, target_ulong *pc, > > target_ulong *cs_base, uint32_t *pflags) > > { > > - uint32_t flags, pstate_for_ss; > > + uint32_t flags = env->hflags; > > + uint32_t pstate_for_ss; > > > > *cs_base = 0; > > - flags = rebuild_hflags_internal(env); > > +#ifdef CONFIG_TCG_DEBUG > > + assert(flags == rebuild_hflags_internal(env)); > > +#endif > > > > - if (is_a64(env)) { > > + if (FIELD_EX32(flags, TBFLAG_ANY, AARCH64_STATE)) { > > *pc = env->pc; > > if (cpu_isar_feature(aa64_bti, env_archcpu(env))) { > > flags = FIELD_DP32(flags, TBFLAG_A64, BTYPE, env->btype); > > > -- > Alex Bennée >
Laurent Desnogues <laurent.desnogues@gmail.com> writes: > On Thu, Sep 5, 2019 at 5:24 PM Alex Bennée <alex.bennee@linaro.org> wrote: >> >> >> 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. >> > >> > Tested-by: Alex Bennée <alex.bennee@linaro.org> >> >> Hmm something must have been missed for M-profile because: >> >> make run-tcg-tests-arm-softmmu V=1 >> >> Leads to: >> >> timeout 15 /home/alex/lsrc/qemu.git/builds/all.debug/arm-softmmu/qemu-system-arm -monitor none -display none -chardev file,path=test-armv6m-undef.out,id=output -semihosting -M microbit -kernel test-armv6m-undef >> qemu: fatal: Lockup: can't escalate 3 to HardFault (current priority -1) >> >> R00=00000000 R01=00000000 R02=00000000 R03=00000000 >> R04=00000000 R05=00000000 R06=00000000 R07=00000000 >> R08=00000000 R09=00000000 R10=00000000 R11=00000000 >> R12=00000000 R13=20003fe0 R14=fffffff9 R15=000000c0 >> XPSR=41000003 -Z-- T handler >> FPSCR: 00000000 >> timeout: the monitored command dumped core >> >> But annoyingly not shown up by the debug-tcg verification. The commit >> before works fine. > > There's a typo in the patch: that should not be CONFIG_TCG_DEBUG but > CONFIG_DEBUG_TCG. With this you should see the assert fire. Indeed: cpu_get_tb_cpu_state: cache 110000c0 <> 312000c0 I wish there was an assert form that would handily print out the difference between the two values. I wonder if glib has one... > > I let Richard know that there's an issue with the handling of CPSR E > flag (BE_DATA in hflags). I don't know if that applies to your test. > > Thanks, > > Laurent > >> > Reviewed-by: Alex Bennée <alex.bennee@linaro.org> >> > Signed-off-by: Richard Henderson <richard.henderson@linaro.org> >> > --- >> > v2: Retain asserts for future debugging. >> > --- >> > target/arm/helper.c | 9 ++++++--- >> > 1 file changed, 6 insertions(+), 3 deletions(-) >> > >> > diff --git a/target/arm/helper.c b/target/arm/helper.c >> > index d1bf71a260..5e4f996882 100644 >> > --- a/target/arm/helper.c >> > +++ b/target/arm/helper.c >> > @@ -11211,12 +11211,15 @@ void HELPER(rebuild_hflags_a64)(CPUARMState *env, int el) >> > void cpu_get_tb_cpu_state(CPUARMState *env, target_ulong *pc, >> > target_ulong *cs_base, uint32_t *pflags) >> > { >> > - uint32_t flags, pstate_for_ss; >> > + uint32_t flags = env->hflags; >> > + uint32_t pstate_for_ss; >> > >> > *cs_base = 0; >> > - flags = rebuild_hflags_internal(env); >> > +#ifdef CONFIG_TCG_DEBUG >> > + assert(flags == rebuild_hflags_internal(env)); >> > +#endif >> > >> > - if (is_a64(env)) { >> > + if (FIELD_EX32(flags, TBFLAG_ANY, AARCH64_STATE)) { >> > *pc = env->pc; >> > if (cpu_isar_feature(aa64_bti, env_archcpu(env))) { >> > flags = FIELD_DP32(flags, TBFLAG_A64, BTYPE, env->btype); >> >> >> -- >> Alex Bennée >> -- Alex Bennée
On 9/5/19 11:50 AM, Alex Bennée wrote: > I wish there was an assert form that would handily print out the > difference between the two values. I wonder if glib has one... g_assert_cmphex(), but checkpatch.pl flags its use because there's a glib environment variable that disables the assert. r~
diff --git a/target/arm/helper.c b/target/arm/helper.c index d1bf71a260..5e4f996882 100644 --- a/target/arm/helper.c +++ b/target/arm/helper.c @@ -11211,12 +11211,15 @@ void HELPER(rebuild_hflags_a64)(CPUARMState *env, int el) void cpu_get_tb_cpu_state(CPUARMState *env, target_ulong *pc, target_ulong *cs_base, uint32_t *pflags) { - uint32_t flags, pstate_for_ss; + uint32_t flags = env->hflags; + uint32_t pstate_for_ss; *cs_base = 0; - flags = rebuild_hflags_internal(env); +#ifdef CONFIG_TCG_DEBUG + assert(flags == rebuild_hflags_internal(env)); +#endif - if (is_a64(env)) { + if (FIELD_EX32(flags, TBFLAG_ANY, AARCH64_STATE)) { *pc = env->pc; if (cpu_isar_feature(aa64_bti, env_archcpu(env))) { flags = FIELD_DP32(flags, TBFLAG_A64, BTYPE, env->btype);
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. Tested-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Alex Bennée <alex.bennee@linaro.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org> --- v2: Retain asserts for future debugging. --- target/arm/helper.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)