lkml.org 
[lkml]   [2008]   [May]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
SubjectRe: [PATCH] msi: skip calling pci_find_capability from msi_set_mask_bits
Date
On Sunday, May 18, 2008 9:48 pm Hidetoshi Seto wrote:
> Jesse Barnes wrote:
> > Since we know MSI is a problem, let's just go with fixing that for now.
> > If we find that other caps are also causing problems we can revisit
> > caching all of them; the patch is simple enough.
>
> Humm...
> I suppose it can be more simple. How about this patch?
>
> > everytime handle_edge_irq is called it needs to mask and unmask MSI, and
> > that leads to a series of very expensive calls to pci_find_capability
>
> The position of MSI capability is already cached in the msi_desc when
> we enter the msi_set_mask_bits(). Use it instead.
>
> Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>

Yeah, this looks really nice. It should also fix Arnaldo's latency problem,
and really looks like a bug fix for the MSI code more than anything.

Arnaldo, can you take a look & test and ack/nack?

Thanks,
Jesse


\
 
 \ /
  Last update: 2008-05-19 22:15    [W:1.507 / U:0.016 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site