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Date: Sun, 08 Feb 2015 21:01:29 +0100
From: Olivier MATZ <olivier.matz@6wind.com>
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To: Cunming Liang <cunming.liang@intel.com>, dev@dpdk.org
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Subject: Re: [dpdk-dev] [PATCH v4 14/17] mempool: add support to non-EAL
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Hi,
On 02/02/2015 03:02 AM, Cunming Liang wrote:
> For non-EAL thread, bypass per lcore cache, directly use ring pool.
> It allows using rte_mempool in either EAL thread or any user pthread.
> As in non-EAL thread, it directly rely on rte_ring and it's none preemptive.
> It doesn't suggest to run multi-pthread/cpu which compete the rte_mempool.
> It will get bad performance and has critical risk if scheduling policy is RT.
>
> Signed-off-by: Cunming Liang <cunming.liang@intel.com>
> ---
> lib/librte_mempool/rte_mempool.h | 18 +++++++++++-------
> 1 file changed, 11 insertions(+), 7 deletions(-)
>
> diff --git a/lib/librte_mempool/rte_mempool.h b/lib/librte_mempool/rte_mempool.h
> index 3314651..4845f27 100644
> --- a/lib/librte_mempool/rte_mempool.h
> +++ b/lib/librte_mempool/rte_mempool.h
> @@ -198,10 +198,12 @@ struct rte_mempool {
> * Number to add to the object-oriented statistics.
> */
> #ifdef RTE_LIBRTE_MEMPOOL_DEBUG
> -#define __MEMPOOL_STAT_ADD(mp, name, n) do { \
> - unsigned __lcore_id = rte_lcore_id(); \
> - mp->stats[__lcore_id].name##_objs += n; \
> - mp->stats[__lcore_id].name##_bulk += 1; \
> +#define __MEMPOOL_STAT_ADD(mp, name, n) do { \
> + unsigned __lcore_id = rte_lcore_id(); \
> + if (__lcore_id < RTE_MAX_LCORE) { \
> + mp->stats[__lcore_id].name##_objs += n; \
> + mp->stats[__lcore_id].name##_bulk += 1; \
> + } \
Does it mean that we have no statistics for non-EAL threads?
(same question for rings and timers in the next patches)
> } while(0)
> #else
> #define __MEMPOOL_STAT_ADD(mp, name, n) do {} while(0)
> @@ -767,8 +769,9 @@ __mempool_put_bulk(struct rte_mempool *mp, void * const *obj_table,
> __MEMPOOL_STAT_ADD(mp, put, n);
>
> #if RTE_MEMPOOL_CACHE_MAX_SIZE > 0
> - /* cache is not enabled or single producer */
> - if (unlikely(cache_size == 0 || is_mp == 0))
> + /* cache is not enabled or single producer or none EAL thread */
> + if (unlikely(cache_size == 0 || is_mp == 0 ||
> + lcore_id >= RTE_MAX_LCORE))
> goto ring_enqueue;
>
> /* Go straight to ring if put would overflow mem allocated for cache */
> @@ -952,7 +955,8 @@ __mempool_get_bulk(struct rte_mempool *mp, void **obj_table,
> uint32_t cache_size = mp->cache_size;
>
> /* cache is not enabled or single consumer */
> - if (unlikely(cache_size == 0 || is_mc == 0 || n >= cache_size))
> + if (unlikely(cache_size == 0 || is_mc == 0 ||
> + n >= cache_size || lcore_id >= RTE_MAX_LCORE))
> goto ring_dequeue;
>
> cache = &mp->local_cache[lcore_id];
>
What is the performance impact of adding this test?
Regards,
Olivier