From: Olivier MATZ <olivier.matz@6wind.com>
To: Jerin Jacob <jerin.jacob@caviumnetworks.com>
Cc: dev@dpdk.org, thomas.monjalon@6wind.com,
bruce.richardson@intel.com, konstantin.ananyev@intel.com
Subject: Re: [dpdk-dev] [PATCH v2] mempool: replace c memcpy code semantics with optimized rte_memcpy
Date: Thu, 2 Jun 2016 09:36:34 +0200 [thread overview]
Message-ID: <574FE202.2060306@6wind.com> (raw)
In-Reply-To: <20160601070018.GA26922@localhost.localdomain>
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
next prev parent reply other threads:[~2016-06-02 7:36 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-24 14:50 [dpdk-dev] [PATCH] mbuf: " Jerin Jacob
2016-05-24 14:59 ` Olivier Matz
2016-05-24 15:17 ` Jerin Jacob
2016-05-27 10:24 ` Hunt, David
2016-05-27 11:42 ` Jerin Jacob
2016-05-27 15:05 ` Thomas Monjalon
2016-05-30 8:44 ` Olivier Matz
2016-05-27 13:45 ` Hunt, David
2016-06-24 15:56 ` Hunt, David
2016-06-24 16:02 ` Olivier Matz
2016-05-26 8:07 ` [dpdk-dev] [PATCH v2] mempool: " Jerin Jacob
2016-05-30 8:45 ` Olivier Matz
2016-05-31 12:58 ` Jerin Jacob
2016-05-31 21:05 ` Olivier MATZ
2016-06-01 7:00 ` Jerin Jacob
2016-06-02 7:36 ` Olivier MATZ [this message]
2016-06-02 9:39 ` Jerin Jacob
2016-06-02 21:16 ` Olivier MATZ
2016-06-03 7:02 ` Jerin Jacob
2016-06-17 10:40 ` Olivier Matz
2016-06-24 16:04 ` Olivier Matz
2016-06-30 9:41 ` Thomas Monjalon
2016-06-30 11:38 ` Jerin Jacob
2016-06-30 12:16 ` [dpdk-dev] [PATCH v3] " Jerin Jacob
2016-06-30 17:28 ` Thomas Monjalon
2016-07-05 8:43 ` Ferruh Yigit
2016-07-05 11:32 ` Yuanhan Liu
2016-07-05 13:13 ` Jerin Jacob
2016-07-05 13:42 ` Yuanhan Liu
2016-07-05 14:09 ` Ferruh Yigit
2016-07-06 16:21 ` Ferruh Yigit
2016-07-07 13:51 ` Ferruh Yigit
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