[RFC v2 3/5] random: keep PRNG state in lcore variable

[Mattias Rönnblom]

On 2024-02-19 12:22, Morten Brørup wrote:
>> From: Mattias Rönnblom [mailto:mattias.ronnblom at ericsson.com]
>> Sent: Monday, 19 February 2024 10.41
>>
>> Replace keeping PRNG state in a RTE_MAX_LCORE-sized static array of
>> cache-aligned and RTE_CACHE_GUARDed struct instances with keeping the
>> same state in a more cache-friendly lcore variable.
>>
>> Signed-off-by: Mattias Rönnblom <mattias.ronnblom at ericsson.com>
>> ---
> 
> [...]
> 
>> @@ -19,14 +20,12 @@ struct rte_rand_state {
>>   	uint64_t z3;
>>   	uint64_t z4;
>>   	uint64_t z5;
>> -	RTE_CACHE_GUARD;
>> -} __rte_cache_aligned;
>> +};
>>
>> -/* One instance each for every lcore id-equipped thread, and one
>> - * additional instance to be shared by all others threads (i.e., all
>> - * unregistered non-EAL threads).
>> - */
>> -static struct rte_rand_state rand_states[RTE_MAX_LCORE + 1];
>> +RTE_LCORE_VAR_HANDLE(struct rte_rand_state, rand_state);
>> +
>> +/* instance to be shared by all unregistered non-EAL threads */
>> +static struct rte_rand_state unregistered_rand_state
>> __rte_cache_aligned;
> 
> The unregistered_rand_state instance is still __rte_cache_aligned; consider also adding an RTE_CACHE_GUARD to it.
> 

It shouldn't be cache-line aligned. I'll remove it. Thanks.