[dpdk-dev] About "Multi-process" sample application

[dvr <jinxiu.1006@163.com>]

hi,all
    I tried to run multi-process sample application step by step according to the document of "sample_application_user_guide.pdf", but encount a problem: only the first rx_queue can receive packages, the other three rx_queue have no package at all. How could this happen? Did I need to do some other configuration?
    Any help will be appreciate.
Best regards.
Maria
    
From dmitryvyal@gmail.com  Thu Sep 12 09:52:00 2013
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Date: Thu, 12 Sep 2013 11:52:35 +0400
From: Dmitry Vyal <dmitryvyal@gmail.com>
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Subject: [dpdk-dev] Looks like rte_mempool_free_count() and
	rte_mempool_count() are swapped
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Greetings.

I had a suspect I run into a mbuf depletion issue and decided to check 
using rte_mempool_free_count(). To my surprise, it returned a value 
equal to mempool size. I tried calling rte_mempool_count() and it 
returned zero.

I inspected the code in dpdk-1.3.1-7 and dpdk.1.4.1-4:

rte_mempool_count(const struct rte_mempool *mp)
{
     unsigned count;

     count = rte_ring_count(mp->ring);

#if RTE_MEMPOOL_CACHE_MAX_SIZE > 0
     {
         unsigned lcore_id;
         if (mp->cache_size == 0)
             return count;

         for (lcore_id = 0; lcore_id < RTE_MAX_LCORE; lcore_id++)
             count += mp->local_cache[lcore_id].len;
     }
#endif

     /*
      * due to race condition (access to len is not locked), the
      * total can be greater than size... so fix the result
      */
     if (count > mp->size)
         return mp->size;
     return count;
}

If I understand it correctly, the ring contains free buffers and 
rte_ring_count() returns a number of entries inside a ring. So this 
function actually calculates the number of free entries, not busy.

Moreover, rte_mempool_count() is used in many places. For example it's 
called in rte_mempool_free_count() and rte_mempool_full().

Can anyone confirm or refute my findings?

Regards,
Dmitry