Re: Making rte_eal_pci_probe() in rte_eal_init() optional?

["Roger B. Melton" <rmelton@cisco.com>]

Hi David,


On 11/13/15 3:49 AM, David Marchand wrote:
> Hello Roger,
>
> On Thu, Nov 12, 2015 at 11:43 PM, Roger B Melton <rmelton@cisco.com 
> <mailto:rmelton@cisco.com>> wrote:
>
>     Hi folks,
>
>     With the addition of hot plug support we have been migrating away
>     from device discovery and attach at initialization time to a model
>     where it is controlled from a separate process.  The separate
>     process manages the binding of devices to UIO and instructs the
>     DPDK process when to attach.  One of the problems we stumbled onto
>     was that if our control process discovered devices and bound them
>     to UIO before our DPDK process started, then rte_eal_init() would
>     discover and attach to those devices via the rte_eal_pci_probe()
>     invocation. This caused problems later on when when our control
>     process, instructed our DPDK process to attach to a device.
>
>     There are a number of ways we could address this, but the simplest
>     is to prevent the rte_eal_pci_probe() at rte_eal_init() time.  In
>     our model we will never need it and I suspect others may also be
>     in that boat.
>
>     What are your thoughts on adding an argument to instruct
>     rte_eal_init() to skip the PCI probe?
>
>
> Did you try the --no-pci option ?
> It avoids the initial sysfs scan, so with no pci device, the initial 
> pci_probe should do nothing.
>
> Attaching devices later will trigger this sysfs scan and only probe 
> the requested device.
> I am not totally happy with the way it is done right now, but I think 
> this should work for you.

I saw it, but I was so caught up in the probe that I didn't consider 
that delaying the scan until attach time might solve the problem.

I'll give it shot.  Thanks for pointing it out David.

Regards,
-Roger

>
>
> -- 
> David Marchand

-- 
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