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* [dpdk-dev] Making rte_eal_pci_probe() in rte_eal_init() optional?
@ 2015-11-12 22:43 Roger B Melton
  2015-11-13  8:49 ` David Marchand
  0 siblings, 1 reply; 13+ messages in thread
From: Roger B Melton @ 2015-11-12 22:43 UTC (permalink / raw)
  To: dev

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?

Thanks,
-Roger

^ permalink raw reply	[flat|nested] 13+ messages in thread
* Re: [dpdk-dev] Making rte_eal_pci_probe() in rte_eal_init() optional?
@ 2015-11-13 22:58 Don Provan
  2015-11-13 23:03 ` Jan Viktorin
  2015-11-14 15:55 ` Roger B. Melton
  0 siblings, 2 replies; 13+ messages in thread
From: Don Provan @ 2015-11-13 22:58 UTC (permalink / raw)
  To: David Marchand, Roger B Melton; +Cc: dev

--no-pci is cool. I'm pretty sure that wasn't there when the PCI scan was first added to
the library init routine. I'm glad to see it, so thanks for pointing it out.

Just for the record: The comment says, "for debug purposes, PCI can be disabled".
This exhibits one of those classic DPDK blindspots. The library can be used for many
things entirely unrelated to hardware. My project has several DPDK applications
intended to be used by users that do not have privs to mess around with PCI
hardware, so, for them, turning off PCI wouldn't be just for debugging purposes.

-don provan
dprovan@bivio.net

-----Original Message-----
From: David Marchand [mailto:david.marchand@6wind.com] 
Sent: Friday, November 13, 2015 12:50 AM
To: Roger B Melton <rmelton@cisco.com>
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] Making rte_eal_pci_probe() in rte_eal_init() optional?

...
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.
...


^ permalink raw reply	[flat|nested] 13+ messages in thread

end of thread, other threads:[~2015-11-21 12:54 UTC | newest]

Thread overview: 13+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-11-12 22:43 [dpdk-dev] Making rte_eal_pci_probe() in rte_eal_init() optional? Roger B Melton
2015-11-13  8:49 ` David Marchand
2015-11-13 12:07   ` Roger B. Melton
2015-11-13 22:58 Don Provan
2015-11-13 23:03 ` Jan Viktorin
2015-11-14 15:55 ` Roger B. Melton
2015-11-14 17:51   ` David Marchand
2015-11-15 14:45     ` Roger B. Melton
2015-11-16  9:46       ` David Marchand
2015-11-17 13:56         ` Roger B. Melton
2015-11-17 15:46           ` Thomas Monjalon
2015-11-18 22:13             ` Roger B. Melton
2015-11-21 12:54               ` Roger B. Melton

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