Re: [dpdk-dev] [PATCH] Added Spinlock to l3fwd-vf example to prevent race conditioning

[Thomas Monjalon <thomas.monjalon@6wind.com>]

Hi Daniel,

This old patch is probably good but I'd like you explain it please.
Reviewers are also welcome.

Thanks
-- 
Thomas

2014-07-23 10:33, Thomas Monjalon:
> Hi Daniel,
> 
> Some explanations are missing here.
> 
> > Signed-off-by: Daniel Mrzyglod <danielx.t.mrzyglod@intel.com>
> > 
> > --- a/examples/l3fwd-vf/main.c
> > +++ b/examples/l3fwd-vf/main.c
> > @@ -54,6 +54,7 @@
> >  #include <rte_per_lcore.h>
> >  #include <rte_launch.h>
> >  #include <rte_atomic.h>
> > +#include <rte_spinlock.h>
> >  #include <rte_cycles.h>
> >  #include <rte_prefetch.h>
> >  #include <rte_lcore.h>
> > @@ -328,7 +329,7 @@ struct lcore_conf {
> >  } __rte_cache_aligned;
> >  
> >  static struct lcore_conf lcore_conf[RTE_MAX_LCORE];
> > -
> > +static rte_spinlock_t spinlock_conf[RTE_MAX_ETHPORTS]={RTE_SPINLOCK_INITIALIZER};
> >  /* Send burst of packets on an output interface */
> >  static inline int
> >  send_burst(struct lcore_conf *qconf, uint16_t n, uint8_t port)
> > @@ -340,7 +341,10 @@ send_burst(struct lcore_conf *qconf, uint16_t n, uint8_t port)
> >  	queueid = qconf->tx_queue_id;
> >  	m_table = (struct rte_mbuf **)qconf->tx_mbufs[port].m_table;
> >  
> > +	rte_spinlock_lock(&spinlock_conf[port]) ;
> >  	ret = rte_eth_tx_burst(port, queueid, m_table, n);
> > +	rte_spinlock_unlock(&spinlock_conf[port]);
> > +	
> >  	if (unlikely(ret < n)) {
> >  		do {
> >  			rte_pktmbuf_free(m_table[ret]);
> >