qemu-e2k/target
Richard Henderson e979972a6a target/arm: Rely on hflags correct in cpu_get_tb_cpu_state
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>
Message-id: 20191023150057.25731-25-richard.henderson@linaro.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
2019-10-24 17:16:28 +01:00
..
alpha
arm target/arm: Rely on hflags correct in cpu_get_tb_cpu_state 2019-10-24 17:16:28 +01:00
cris
hppa
i386 target/i386: Introduce Denverton CPU model 2019-10-23 23:37:42 -03:00
lm32
m68k
microblaze
mips
moxie
nios2
openrisc
ppc target/ppc: Fix for optimized vsl/vsr instructions 2019-10-24 09:36:55 +11:00
riscv
s390x s390x/kvm: Set default cpu model for all machine classes 2019-10-21 18:03:08 +02:00
sh4
sparc
tilegx
tricore
unicore32
xtensa target/xtensa: regenerate and re-import test_mmuhifi_c3 core 2019-10-18 19:54:27 -07:00