[Mesa-dev] [PATCH 02/70] i965: Pack read-only booleans into a bitfield

Chris Wilson chris at chris-wilson.co.uk
Mon Aug 10 02:59:07 PDT 2015

On Fri, Aug 07, 2015 at 09:13:06PM +0100, Chris Wilson wrote:
> GCC's read access for single bits in a bitfield is reasonable (just a
> move + flag comparison), so let's save some cachelines by packing the
> write-once/read-many booleans together.
>    text	   data	    bss	    dec	    hex	filename
> 6490134	 191992	  26192	6708318	 665c5e	lib64/i965_dri.so
> 6491766	 191992	  26192	6709950	 6662be	lib64/i965_dri.so
> Small inflation due to the extra immediate masks and entirely dubious as
> to whether it is worth it.

A run though Martin's testsuite on Braswell also suggests the extra code
hurts noticeably, so just ignore this patch...

Chris Wilson, Intel Open Source Technology Centre

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