lkml.org 
[lkml]   [2008]   [Sep]   [25]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Notes from LPC PCI/MSI BoF session
On Tue, Sep 23, 2008 at 11:47:05PM -0700, David Miller wrote:
> From: Grant Grundler <grundler@parisc-linux.org>
> Date: Tue, 23 Sep 2008 23:51:16 -0600
>
> > Dave Miller (and others) have clearly stated they don't want to see
> > CPU affinity handled in the device drivers and want irqbalanced
> > to handle interrupt distribution. The problem with this is irqbalanced
> > needs to know how each device driver is binding multiple MSI to it's queues.
> > Some devices could prefer several MSI go to the same processor and
> > others want each MSI bound to a different "node" (NUMA).
> >
> > Without any additional API, this means the device driver has to
> > update irqbalanced for each device it supports. We thought pci_ids.h
> > was a PITA...that would be trivial compared to maintaining this.
>
> We just need a consistent naming scheme for the IRQs to disseminate
> this information to irqbalanced, then there is one change to irqbalanced
> rather than one for each and every driver as you seem to suggest.

That's sort of what I proposed at the end of my email:
| A second solution I thought of later might be for the device driver to
| export (sysfs?) to irqbalanced which MSIs the driver instance owns and
| how many "domains" those MSIs can serve. irqbalanced can then write
| back into the same (sysfs?) the mapping of MSI to domains and update
| the smp_affinity mask for each of those MSI.

> Anything that's complicated and takes more than a paragraph or two
> to describe is not what we want.

I agree. The discussion will need more though.

thanks,
grant

> --
> To unsubscribe from this list: send the line "unsubscribe linux-pci" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html


\
 
 \ /
  Last update: 2008-09-25 17:57    [W:0.046 / U:0.416 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site