included netdev... On 11/8/06, Jeff V. Merkey <[EMAIL PROTECTED]> wrote:
Is there a good reason the skb refill routine in e1000_alloc_rx_buffers needs to go and touch and remap skb memory on already loaded descriptors/ This seems extremely wasteful of processor cycles when refilling the ring buffer. I note that the archtiecture has changed and is recycling buffers from the rx_irq routine and when the routine is called to refill the ring buffers, a lot of wasteful and needless calls for map_skb is occurring.
we have to unmap the descriptor (or at least do pci_dma_sync_single_for_cpu / pci_dma_sync_single_for_device) because the dma API says we can't be guaranteed the cacheable memory is consistent until we do one of the afore mentioned pci dma ops. we have to do *something* before we access it. Simplest path is to unmap it and then recycle/map it. If you can show that it is faster to use pci_dma_sync_single_for_cpu and friends I'd be glad to take a patch. Hope this helps, Jesse - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
