[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] Dom0 physical networking/swiotlb/something issue in 3.7-rc1
>>> On 09.11.12 at 10:16, Ian Campbell <Ian.Campbell@xxxxxxxxxx> wrote: > On Fri, 2012-11-09 at 09:03 +0000, Jan Beulich wrote: >> >>> On 12.10.12 at 12:28, Ian Campbell <Ian.Campbell@xxxxxxxxxx> wrote: >> > The following patch causes fairly large packet loss when transmitting >> > from dom0 to the physical network, at least with my tg3 hardware, but I >> > assume it can impact anything which uses this interface. >> > >> > I suspect that the issue is that the compound pages allocated in this >> > way are not backed by contiguous mfns and so things fall apart when the >> > driver tries to do DMA. >> >> Has this seen any sort of resolution yet? Despite having forced >> NETDEV_FRAG_PAGE_MAX_ORDER to zero for Xen (following >> your suggested patch, Ian), and with a different NIC (e1000e >> driven) I'm seeing similar packet loss/corruption on transmits, >> and only if running a debug hypervisor (in a non-debug one, >> MFNs are largely contiguous, so this issue should be observable >> there only very rarely). > > I think Konrad is still looking into the underlying swiotlb issue. > > If you want to go with the workaround then there is another order>0 to > frob in net/core/sock.c > #define SKB_FRAG_PAGE_ORDER get_order(32768) > which might help. Thanks, that indeed helped. And gives me food for thought as well, since this should - if anything at all - be a performance improvement, not a something affecting correctness. Jan _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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