Jun Sun writes: > I notice that many net drivers set rx_copybreak to 1518 (the max packet size) > for non-i386 architectures. Once I thought I understood it and it seems > related to cache line alignment. However, I am not sure exactly about the > reason now. Can someone enlighten me a little bit? Most non-x86 architectures take a large hit for unaligned accesses. If the ethernet chip cannot land the beginning of the packet at an arbitrary byte offset (a modulo 2 offset for ethernet is needed for an aligned IP header) then the rx_copybreak is set to the ethernet MTU so that all packets get copied into new buffers where they can have their header aligned. Later, David S. Miller [EMAIL PROTECTED] - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
