Re: [dpdk-dev] [PATCH v2 3/4] common_base: extend RTE_MAX_ETHPORTS from 32 to 1024

["Yang, Zhiyong" <zhiyong.yang@intel.com>]

Hi, Bruce:

> -----Original Message-----
> From: Richardson, Bruce
> Sent: Monday, September 4, 2017 5:09 PM
> To: Yang, Zhiyong <zhiyong.yang@intel.com>
> Cc: Yao, Lei A <lei.a.yao@intel.com>; dev@dpdk.org; thomas@monjalon.net;
> Yigit, Ferruh <ferruh.yigit@intel.com>; Wiles, Keith <keith.wiles@intel.com>;
> stephen@networkplumber.org
> Subject: Re: [dpdk-dev] [PATCH v2 3/4] common_base: extend
> RTE_MAX_ETHPORTS from 32 to 1024
> > > > --- a/config/common_base
> > > > +++ b/config/common_base
> > > > @@ -131,7 +131,7 @@ CONFIG_RTE_LIBRTE_KVARGS=y  #
> > > > CONFIG_RTE_LIBRTE_ETHER=y  CONFIG_RTE_LIBRTE_ETHDEV_DEBUG=n
> > > > -CONFIG_RTE_MAX_ETHPORTS=32
> > > > +CONFIG_RTE_MAX_ETHPORTS=1024
> > > >  CONFIG_RTE_MAX_QUEUES_PER_PORT=1024
> > > >  CONFIG_RTE_LIBRTE_IEEE1588=n
> > > >  CONFIG_RTE_ETHDEV_QUEUE_STAT_CNTRS=16
> > > > --
> > > > 2.13.3
> > > Hi, Zhiyong
> > >
> > > I met one issue for changing CONFIG_RTE_MAX_ETHPORTS to 1024.
> > > One process can only open 1024 file as maximum in common linux
> > > distribution, after practice, only 1009 socket file can be used for
> > > vdev device with testpmd sample.
> >
> > Thanks for your info.  It seems that 1024 is too large and may bring some
> potential issues.
> >
> > Thanks
> > Zhiyong
> >
> 
> It should be possible to have a dynamically allocated ethdev array, which would
> allow use to have a default value - which could be e.g. 32 or 64 as now - while
> also allowing a run-time parameter to increase that to thousands if needed.
> 
> /Bruce

In testpmd,  the following function will be called to validate the port_id. 
So, It is necessary to modify the max port num RTE_MAX_ETHPORTS. 

I think that RTE_MAX_ETHPORTS and  a default value(num of port ) should be different values.
Now dpdk limits the max num to RTE_MAX_ETHPORTS = 32 by default.  
int
rte_eth_dev_is_valid_port(uint16_t port_id)
{
	if (port_id >= RTE_MAX_ETHPORTS ||
	    (rte_eth_devices[port_id].state != RTE_ETH_DEV_ATTACHED &&
	     rte_eth_devices[port_id].state != RTE_ETH_DEV_DEFERRED))
		return 0;
	else
		return 1;
}

Thanks
Zhiyong.