Re: [PATCH v3 3/7] eal: add lcore variable performance test

["Mattias Rönnblom" <hofors@lysator.liu.se>]

On 2024-09-12 15:09, Jerin Jacob wrote:
> On Thu, Sep 12, 2024 at 2:34 PM Mattias Rönnblom
> <mattias.ronnblom@ericsson.com> wrote:
>>
>> Add basic micro benchmark for lcore variables, in an attempt to assure
>> that the overhead isn't significantly greater than alternative
>> approaches, in scenarios where the benefits aren't expected to show up
>> (i.e., when plenty of cache is available compared to the working set
>> size of the per-lcore data).
>>
>> Signed-off-by: Mattias Rönnblom <mattias.ronnblom@ericsson.com>
>> ---
>>   app/test/meson.build           |   1 +
>>   app/test/test_lcore_var_perf.c | 160 +++++++++++++++++++++++++++++++++
>>   2 files changed, 161 insertions(+)
>>   create mode 100644 app/test/test_lcore_var_perf.c
> 
> 
>> +static double
>> +benchmark_access_method(void (*init_fun)(void), void (*update_fun)(void))
>> +{
>> +       uint64_t i;
>> +       uint64_t start;
>> +       uint64_t end;
>> +       double latency;
>> +
>> +       init_fun();
>> +
>> +       start = rte_get_timer_cycles();
>> +
>> +       for (i = 0; i < ITERATIONS; i++)
>> +               update_fun();
>> +
>> +       end = rte_get_timer_cycles();
> 
> Use precise variant. rte_rdtsc_precise() or so to be accurate

With 1e7 iterations, do you need rte_rdtsc_precise()? I suspect not.