Hi Jerin,
On 06/01/2016 09:00 AM, Jerin Jacob wrote:
> On Tue, May 31, 2016 at 11:05:30PM +0200, Olivier MATZ wrote:
>> Today, the objects pointers are reversed only in the get(). It means
>> that this code:
>>
>> rte_mempool_get_bulk(mp, table, 4);
>> for (i = 0; i < 4; i++)
>> printf("obj = %p\n", t[i]);
>> rte_mempool_put_bulk(mp, table, 4);
>>
>>
>> printf("-----\n");
>> rte_mempool_get_bulk(mp, table, 4);
>> for (i = 0; i < 4; i++)
>> printf("obj = %p\n", t[i]);
>> rte_mempool_put_bulk(mp, table, 4);
>>
>> prints:
>>
>> addr1
>> addr2
>> addr3
>> addr4
>> -----
>> addr4
>> addr3
>> addr2
>> addr1
>>
>> Which is quite strange.
>
> IMO, It is the expected LIFO behavior. Right ?
>
> What is not expected is the following, which is the case after change. Or Am I
> missing something here?
>
> addr1
> addr2
> addr3
> addr4
> -----
> addr1
> addr2
> addr3
> addr4
>
>>
>> I don't think it would be an issue to replace the loop by a
>> rte_memcpy(), it may increase the copy speed and it will be
>> more coherent with the put().
>>
I think the LIFO behavior should occur on a per-bulk basis. I mean,
it should behave like in the exemplaes below:
// pool cache is in state X
obj1 = mempool_get(mp)
obj2 = mempool_get(mp)
mempool_put(mp, obj2)
mempool_put(mp, obj1)
// pool cache is back in state X
// pool cache is in state X
bulk1 = mempool_get_bulk(mp, 16)
bulk2 = mempool_get_bulk(mp, 16)
mempool_put_bulk(mp, bulk2, 16)
mempool_put_bulk(mp, bulk1, 16)
// pool cache is back in state X
Note that today it's not the case for bulks, since object addresses
are reversed only in get(), we are not back in the original state.
I don't really see the advantage of this.
Removing the reversing may accelerate the cache in case of bulk get,
I think.
Regards,
Olivier
