Messages in this thread | | | From | (Linus Torvalds) | Subject | Re: Is sendfile all that sexy? | Date | 19 Jan 2001 13:45:09 -0800 |
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In article <200101192018.XAA25263@ms2.inr.ac.ru>, <kuznet@ms2.inr.ac.ru> wrote: >Hello! > >> It's about direct i/o from/to pages, > >Yes. Formally, there are no problems to send to tcp directly from io space.
Actually, as long as there is no "struct page" there _are_ problems. This is why the NUMA stuff was brought up - it would require that there be a mem_map for the PCI pages.. (to do ref-counting etc).
>But could someone explain me one thing. Does bus-mastering >from io really work? And if it does, is it enough fast? >At least, looking at my book on pci, I do not understand >how such transfers are able to use bursts. MRM is banned for them...
It does work at least on some hardware. But no, I don't think you can depend on bursting (but I don't see why it couldn't work in theory).
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