[Intel-gfx] [PATCH] drm/i915: Update write_domains on active list after flush.

Chris Wilson chris at chris-wilson.co.uk
Fri Feb 13 21:55:00 CET 2009

On Fri, 2009-02-13 at 12:14 -0800, Eric Anholt wrote:
> On Wed, 2009-02-11 at 14:26 +0000, Chris Wilson wrote:
> > In order to reduce the time spent searching the active list for matching
> > write_domains, we move those to a separate list whose elements are
> > the buffers belong to the active/flushing list with pending writes.
> I was chatting with keithp about this one yesterday, and we're both a
> little leery of adding more lists unless strictly necessary.  Did you
> find walking the whole active list to be too expensive?  One thought to
> mitigate that without more pointers for us to forget about would be to
> record the last flush's seqno and just walk the active list from head
> until !i915_gem_seqno_passed(buffer->last_rendering_seqno,
> dev_priv->last_flush_seqno).

Yes, this was motivated by i915_add_request() suddenly becoming a
hotspot in the profile after walking the active list in conjunction with
the flushing list. I'll go back, dig up some numbers and compare with
your suggestion.

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