Re: [PATCH v5 06/12] tests/plugin/mem: migrate to new per_vcpu API

["Alex Bennée" <alex.bennee@linaro.org>]

Luc Michel <luc.michel@amd.com> writes:

> Hi Pierrick,
>
> On 13:14 Mon 26 Feb     , Pierrick Bouvier wrote:
>> Signed-off-by: Pierrick Bouvier <pierrick.bouvier@linaro.org>
>> ---
>>  tests/plugin/mem.c | 40 +++++++++++++++++++++++++---------------
>>  1 file changed, 25 insertions(+), 15 deletions(-)
>> 
>> diff --git a/tests/plugin/mem.c b/tests/plugin/mem.c
>> index 44e91065ba7..d4729f5e015 100644
>> --- a/tests/plugin/mem.c
>> +++ b/tests/plugin/mem.c
>> @@ -16,9 +16,14 @@
>> 
>>  QEMU_PLUGIN_EXPORT int qemu_plugin_version = QEMU_PLUGIN_VERSION;
>> 
>> -static uint64_t inline_mem_count;
>> -static uint64_t cb_mem_count;
>> -static uint64_t io_count;
>> +typedef struct {
>> +    uint64_t mem_count;
>> +    uint64_t io_count;
>> +} CPUCount;
>> +
>> +static struct qemu_plugin_scoreboard *counts;
>> +static qemu_plugin_u64 mem_count;
>> +static qemu_plugin_u64 io_count;
>
> I see that you merged inline and callback counts into the same variable.
>
> I wonder... For this test don't you want to keep a plain uint64_t for
> callback counts? I have the feeling that this test was made so one can
> make sure inline and callback counts match.

Indeed the problem now is double counting:

  ➜  ./qemu-hppa -plugin ./tests/plugin/libmem.so,inline=true -d plugin  ./tests/tcg/hppa-linux-user/sha512
  1..10
  ok 1 - do_test(&tests[i])
  ok 2 - do_test(&tests[i])
  ok 3 - do_test(&tests[i])
  ok 4 - do_test(&tests[i])
  ok 5 - do_test(&tests[i])
  ok 6 - do_test(&tests[i])
  ok 7 - do_test(&tests[i])
  ok 8 - do_test(&tests[i])
  ok 9 - do_test(&tests[i])
  ok 10 - do_test(&tests[i])
  mem accesses: 262917
  🕙22:06:57 alex@draig:qemu.git/builds/all  on  plugins/next [$?] 
  ➜  ./qemu-hppa -plugin ./tests/plugin/libmem.so,inline=true,callback=true -d plugin  ./tests/tcg/hppa-linux-user/sha512
  1..10
  ok 1 - do_test(&tests[i])
  ok 2 - do_test(&tests[i])
  ok 3 - do_test(&tests[i])
  ok 4 - do_test(&tests[i])
  ok 5 - do_test(&tests[i])
  ok 6 - do_test(&tests[i])
  ok 7 - do_test(&tests[i])
  ok 8 - do_test(&tests[i])
  ok 9 - do_test(&tests[i])
  ok 10 - do_test(&tests[i])
  mem accesses: 525834

although perhaps it would just be simpler for the plugin to only accept
one or the other method.

>
> Luc
>
>>  static bool do_inline, do_callback;
>>  static bool do_haddr;
>>  static enum qemu_plugin_mem_rw rw = QEMU_PLUGIN_MEM_RW;
>> @@ -27,16 +32,16 @@ static void plugin_exit(qemu_plugin_id_t id, void *p)
>>  {
>>      g_autoptr(GString) out = g_string_new("");
>> 
>> -    if (do_inline) {
>> -        g_string_printf(out, "inline mem accesses: %" PRIu64 "\n", inline_mem_count);
>> -    }
>> -    if (do_callback) {
>> -        g_string_append_printf(out, "callback mem accesses: %" PRIu64 "\n", cb_mem_count);
>> +    if (do_inline || do_callback) {
>> +        g_string_printf(out, "mem accesses: %" PRIu64 "\n",
>> +                        qemu_plugin_u64_sum(mem_count));
>>      }
>>      if (do_haddr) {
>> -        g_string_append_printf(out, "io accesses: %" PRIu64 "\n", io_count);
>> +        g_string_append_printf(out, "io accesses: %" PRIu64 "\n",
>> +                               qemu_plugin_u64_sum(io_count));
>>      }
>>      qemu_plugin_outs(out->str);
>> +    qemu_plugin_scoreboard_free(counts);
>>  }
>> 
>>  static void vcpu_mem(unsigned int cpu_index, qemu_plugin_meminfo_t meminfo,
>> @@ -46,12 +51,12 @@ static void vcpu_mem(unsigned int cpu_index, qemu_plugin_meminfo_t meminfo,
>>          struct qemu_plugin_hwaddr *hwaddr;
>>          hwaddr = qemu_plugin_get_hwaddr(meminfo, vaddr);
>>          if (qemu_plugin_hwaddr_is_io(hwaddr)) {
>> -            io_count++;
>> +            qemu_plugin_u64_add(io_count, cpu_index, 1);
>>          } else {
>> -            cb_mem_count++;
>> +            qemu_plugin_u64_add(mem_count, cpu_index, 1);
>>          }
>>      } else {
>> -        cb_mem_count++;
>> +        qemu_plugin_u64_add(mem_count, cpu_index, 1);
>>      }
>>  }
>> 
>> @@ -64,9 +69,10 @@ static void vcpu_tb_trans(qemu_plugin_id_t id, struct qemu_plugin_tb *tb)
>>          struct qemu_plugin_insn *insn = qemu_plugin_tb_get_insn(tb, i);
>> 
>>          if (do_inline) {
>> -            qemu_plugin_register_vcpu_mem_inline(insn, rw,
>> -                                                 QEMU_PLUGIN_INLINE_ADD_U64,
>> -                                                 &inline_mem_count, 1);
>> +            qemu_plugin_register_vcpu_mem_inline_per_vcpu(
>> +                insn, rw,
>> +                QEMU_PLUGIN_INLINE_ADD_U64,
>> +                mem_count, 1);
>>          }
>>          if (do_callback) {
>>              qemu_plugin_register_vcpu_mem_cb(insn, vcpu_mem,
>> @@ -117,6 +123,10 @@ QEMU_PLUGIN_EXPORT int qemu_plugin_install(qemu_plugin_id_t id,
>>          }
>>      }
>> 
>> +    counts = qemu_plugin_scoreboard_new(sizeof(CPUCount));
>> +    mem_count = qemu_plugin_scoreboard_u64_in_struct(
>> +        counts, CPUCount, mem_count);
>> +    io_count = qemu_plugin_scoreboard_u64_in_struct(counts, CPUCount, io_count);
>>      qemu_plugin_register_vcpu_tb_trans_cb(id, vcpu_tb_trans);
>>      qemu_plugin_register_atexit_cb(id, plugin_exit, NULL);
>>      return 0;
>> --
>> 2.43.0
>> 
>> 

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro