[Skiboot] [PATCH] hw/phb3: Flush cache line after updating P/Q bits

Benjamin Herrenschmidt benh at kernel.crashing.org
Thu Nov 19 18:38:08 AEDT 2015

On Thu, 2015-11-19 at 17:25 +1100, Stewart Smith wrote:
> Benjamin Herrenschmidt <benh at kernel.crashing.org> writes:
> > When doing an MSI EOI, we update the P and Q bits in the IVE. That
> > causes
> > the corresponding cache line to be dirty in the L3 which will cause
> > a
> > subsequent update by the PHB (upon recieving the next MSI) to get a
> > few
> > retries until it gets flushed.
> > 
> > We can improve the situation (and thus performance) by doing a dcbf
> > instruction to force a flush of the update we do in SW.
> > 
> > Signed-off-by: Benjamin Herrenschmidt <benh at kernel.crashing.org>
> For some bizarre reason git (and /usr/bin/patch) told me the patch
> was corrupt, but never mind - applied by hand.

Could be that I failed to set "Preformatted" in evo ... happens

> Merged to update- as of 53def38
> Merged to stable as of b96a20e
> merged to master as of 1cec33c


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