Date: Wed, 9 Feb 2011 10:56:30 +0100 From: Olivier Houchard <mlfbsd@ci0.org> To: Marcel Moolenaar <xcllnt@mac.com> Cc: arm@freebsd.org Subject: Re: Elimination of cpu_l2cache_* functions Message-ID: <20110209095630.GA57320@ci0.org> In-Reply-To: <857AA8D9-5C41-4D80-A3B5-0D29BE051014@mac.com> References: <857AA8D9-5C41-4D80-A3B5-0D29BE051014@mac.com>
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Hi Marcel, On Mon, Feb 07, 2011 at 10:43:54AM -0800, Marcel Moolenaar wrote: > All, > > I've been reviewing the use of the cpu_l2cache_* functions and found > that 1) they're missing from cpu_witch() and 2) they are always used > in conjunction with either cpu_idcache_* or cpu_dcache_*. > > Since most CPU variants define them as null ops, isn't it better to > incorporate the functionality of cpu_l2cache_* in cpu_idcache_* and > cpu_dcache_* and eliminate them altogether? > > Any objections to me removing cpu_l2cache_* and therefore changing > the semantics of cpu_idcache_* and cpu_dcahce_* to apply to all > relevant cache levels? > I chose to make the l2cache functions separate from the [i]dcache functions because there's a number of cases where L1 cache flush was needed, but not L2, and that would be a performance penalty to do both. Also, more CPU variants define them as null ops now, but most new arm cpus come with a L2 cache,, so we need to think about it carefully. Regards, Olivier
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