[Intel-gfx] [PATCH 07/27] drm/i915: Squash repeated awaits on the same fence

[Chris Wilson]

On Wed, Apr 26, 2017 at 07:56:14PM +0100, Chris Wilson wrote:
> On Wed, Apr 26, 2017 at 01:13:41PM +0100, Tvrtko Ursulin wrote:
> > I was thinking of exactly the same thing as this patch does, u64
> > context id as key, u32 seqnos (wrapped in a container with
> > hlist_node).
> 
> #define NSYNC 32
> struct intel_timeline_sync { /* kmalloc-256 slab */
> 	struct hlist_node node;
>         u64 prefix;
> 	u32 bitmap;
> 	u32 seqno[NSYNC];
> };
> DECLARE_HASHTABLE(sync, 7);
> 
> If I squint, the numbers favour the idr. ;)

Hmm, it didn't take much to start running into misery with a static ht.
I know my testing is completely artificial but I am not going to be
happy with a static size, it will always be too big or too small and
never just Goldilocks.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre