[Intel-gfx] sna: Experimental support for write-combining mmaps (wc-mmap)

[Chris Wilson]

On Fri, Nov 07, 2014 at 11:59:26AM +0100, Sedat Dilek wrote:
> On Fri, Nov 7, 2014 at 11:43 AM, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> > On Fri, Nov 07, 2014 at 11:35:01AM +0100, Sedat Dilek wrote:
> >> On Fri, Nov 7, 2014 at 11:29 AM, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> >> > On Fri, Nov 07, 2014 at 11:08:41AM +0100, Sedat Dilek wrote:
> >> >> Hi,
> >> >>
> >> >> I am playing with wc-mmap [1]... (and sent a trivial patch [0]).
> >> >>
> >> >> Inspecting my logs...
> >> >>
> >> >> $ egrep 'wc|mmap'
> >> >> logs/build-and-install-log_XF86-Video-Intel-v2-99-916-137-g0aa2edb_WCMMAP_llvm-3-4-2.txt
> >> >>   Experimental support: TearFree mmap(wc)
> >> >>
> >> >> $ egrep -i 'wc|mmap|write|comb' /var/log/Xorg.0.log
> >> >> [ EMPTY ]
> >> >>
> >> >> TearFree [1] can be set via an option in xorg.conf.
> >> >> Doing a very quick look into the sources, such a flag/option is not recognized.
> >> >>
> >> >> How do I see if wc-mmap is enabled/active on my desktop?
> >> >
> >> > Er, hopefully you don't notice anything except it speeds up certain
> >> > operations (quite considerably) :). You have to enable the DBG output to
> >> > see it in action, as it is quite a lowlevel feature (i.e. how we
> >> > interact with the kernel) and should not add any user visible features.
> >> > However, it does also require the kernel patch for it to be enabled.
> >>
> >> Can you point me to that kernel-patch?
> >> Is Linux v3.18-rc2+ good enough or do I need d-i-l-n / d-i-n?
> >
> 
> Hmm... against which trees are those patches?
> 
> > http://patchwork.freedesktop.org/patch/35049/
> "drm/i915: Broaden application of set-domain(GTT)"
> 
> ...is not applicable against d-i-f or d-i-n.

Try
http://cgit.freedesktop.org/~ickle/linux-2.6/commit/?h=nightly&id=2b03060c7585df31e6e90fef91af4064769bf394
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre