On Mon, Jun 27, 2011 at 03:19:43PM +0200, Arnd Bergmann wrote: > > > I suppose for the majority of the cases, the overhead of the indirect > > > function call is near-zero, compared to the overhead of the cache > > > management operation, so it would only make a difference for coherent > > > systems without an IOMMU. Do we care about micro-optimizing those? FWIW, when I was hacking on ARM access point routing performance some time ago, turning the L1/L2 cache maintenance operations into inline functions (inlined into the ethernet driver) gave me a significant and measurable performance boost. Such things can remain product-specific hacks, though. > > Even in coherent case, the overhead caused by additional function call > > should have really negligible impact on drivers performance. > > What about object code size? I guess since ixp23xx is the only platform > that announces itself as coherent, we probably don't need to worry about > it too much either. Lennert? I don't think so. ixp23xx isn't a very popular platform anymore either, having been discontinued some time ago. thanks, Lennert -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>