Re: [PATCHv1 1/5] arm64: dts: amlogic: Add cache information to the Amlogic GXBB and GXL SoC

[Anand Moon <linux.amoon@gmail.com>]

Hi Neil,

On Mon, 5 Feb 2024 at 22:50, Anand Moon <linux.amoon@gmail.com> wrote:
>
> As per S905 and S905X datasheet add missing cache information to
> the Amlogic GXBB and GXL SoC.
>
> - Each Cortex-A53 core has 32KB of L1 instruction cache available and
>         32KB of L1 data cache available.
> - Along with 512KB Unified L2 cache.
>
> To improve system performance.
>
> Signed-off-by: Anand Moon <linux.amoon@gmail.com>
> ---
> Datasheet
> [0] https://dn.odroid.com/S905/DataSheet/S905_Public_Datasheet_V1.1.4.pdf
> ---

As per the Arm Cortex A53 TRM documentation
[0] https://developer.arm.com/documentation/ddi0500/j/Introduction/Implementation-options?lang=en

Since this SoC supports arm-pmu we could  read cache info using perf
[1] https://www.baeldung.com/linux/analyze-cache-misses

[alarm@archl-librecm ~]$ sudo perf list

List of pre-defined events (to be used in -e or -M):

  branch-instructions OR branches                    [Hardware event]
  branch-misses                                      [Hardware event]
  bus-cycles                                         [Hardware event]
  cache-misses                                       [Hardware event]
  cache-references                                   [Hardware event]
  cpu-cycles OR cycles                               [Hardware event]
  instructions                                       [Hardware event]
  alignment-faults                                   [Software event]
  bpf-output                                         [Software event]
  cgroup-switches                                    [Software event]
  context-switches OR cs                             [Software event]
  cpu-clock                                          [Software event]
  cpu-migrations OR migrations                       [Software event]
  dummy                                              [Software event]
  emulation-faults                                   [Software event]
  major-faults                                       [Software event]
  minor-faults                                       [Software event]
  page-faults OR faults                              [Software event]
  task-clock                                         [Software event]
  duration_time                                      [Tool event]
  user_time                                          [Tool event]
  system_time                                        [Tool event]

armv8_cortex_a53:
  L1-dcache-loads OR armv8_cortex_a53/L1-dcache-loads/
  L1-dcache-load-misses OR armv8_cortex_a53/L1-dcache-load-misses/
  L1-dcache-prefetch-misses OR armv8_cortex_a53/L1-dcache-prefetch-misses/
  L1-icache-loads OR armv8_cortex_a53/L1-icache-loads/
  L1-icache-load-misses OR armv8_cortex_a53/L1-icache-load-misses/
  dTLB-load-misses OR armv8_cortex_a53/dTLB-load-misses/
  iTLB-load-misses OR armv8_cortex_a53/iTLB-load-misses/
  branch-loads OR armv8_cortex_a53/branch-loads/
  branch-load-misses OR armv8_cortex_a53/branch-load-misses/
  node-loads OR armv8_cortex_a53/node-loads/
  node-stores OR armv8_cortex_a53/node-stores/
  br_immed_retired OR armv8_cortex_a53/br_immed_retired/[Kernel PMU event]
  br_mis_pred OR armv8_cortex_a53/br_mis_pred/       [Kernel PMU event]
  br_pred OR armv8_cortex_a53/br_pred/               [Kernel PMU event]
  bus_access OR armv8_cortex_a53/bus_access/         [Kernel PMU event]
  bus_cycles OR armv8_cortex_a53/bus_cycles/         [Kernel PMU event]
  cid_write_retired OR armv8_cortex_a53/cid_write_retired/[Kernel PMU event]
  cpu_cycles OR armv8_cortex_a53/cpu_cycles/         [Kernel PMU event]
  exc_return OR armv8_cortex_a53/exc_return/         [Kernel PMU event]

[alarm@archl-librecm ~]$ perf stat -B -e
cache-references,cache-misses,cycles,instructions,branches,faults,migrations
sleep 5

 Performance counter stats for 'sleep 5':

             52794      cache-references:u
              2311      cache-misses:u                   #    4.38% of
all cache refs
            480343      cycles:u
            140018      instructions:u                   #    0.29
insn per cycle
             15012      branches:u
                46      faults:u
                 0      migrations:u

       5.008073381 seconds time elapsed

       0.000000000 seconds user
       0.006952000 seconds sys

Thanks



-Anand

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