On Mon, May 12, 2014 at 03:49:02PM +0100, Tvrtko Ursulin wrote: > > On 05/10/2014 10:10 PM, bradley.d.volkin@xxxxxxxxx wrote: > >From: Brad Volkin <bradley.d.volkin@xxxxxxxxx> > > > >For clients that submit large batch buffers the command parser has > >a substantial impact on performance. On my HSW ULT system performance > >drops as much as ~20% on some tests. Most of the time is spent in the > >command lookup code. Converting that from the current naive search to > >a hash table lookup reduces the performance drop to ~10%. > > > >The choice of value for I915_CMD_HASH_ORDER allows all commands > >currently used in the parser tables to hash to their own bucket (except > >for one collision on the render ring). The tradeoff is that it wastes > >memory. Because the opcodes for the commands in the tables are not > >particularly well distributed, reducing the order still leaves many > >buckets empty. The increased collisions don't seem to have a huge > >impact on the performance gain, but for now anyhow, the parser trades > >memory for performance. > > > >NB: Ville noticed that the error paths through the ring init code > >will leak memory. I've not addressed that here. We can do a follow > >up pass to handle all of the leaks. > > > >v2: improved comment describing selection of hash key mask (Damien) > >replace a BUG_ON() with an error return (Tvrtko, Ville) > >commit message improvements > > > >Signed-off-by: Brad Volkin <bradley.d.volkin@xxxxxxxxx> > > Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx> Nice. Queued for -next, thanks for the patch. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
