On Thu, Mar 15, 2012 at 12:39:30AM -0700, Juli Mallett wrote: > All, > > On both stable/9 and trunk I see that with one of either the 82571EB > or 82574L I am flooded with messages in the form of: > > Refresh mbufs: hdr dmamap load failure - 22 > > If I disable msix, then the messages go away. I am not sure why msix > vs. non-msix would matter in this case unless in the msix case there's > some kind of case of spurious interrupts causing em_rxeof to be called > without any packets available. If that happens then perhaps > e1000_rx_unrefreshed() is called when no buffers have been processed > and then em_refresh_mbufs wrongly refreshes the whole ring? > > This seems like it would be a problem because the > bus_dmamap_load_mbuf_sg code is called unconditionally, even when a > new mbuf isn't being allocated. In that case, the mapping already > exists. Wouldn't it be necessary to unload and then reload the mbuf? > So either it's a bug that em_refresh_mbufs is being called at all, or > it's naively reusing mbufs in a way that actually guarantees an error, > right? Also, in the case where it frees, only m_free is called ??? is > there never a case where that should be an m_freem? I can imagine > some, but they are likely impossible with the receive path of the > driver. (I don't know for sure because the receive path and the mbuf > refresh code keep changing and I've been unable to keep up.) > > I don't know which part it is, of course, because I don't know what > port it's coming from. Like three other printfs in the driver where > which device is being used matters tremendously, it uses a bare printf > and not a device_printf. I could modify the driver, but for now > disabling msix is easier than continuing to load new kernels to try to > debug the problem. > > Is anyone else seeing this? Has anyone further investigated the
Some time ago I also tried to debug low performance issue of 82574. At that time I didn't encounter the issue you mentioned but I saw spurious interrupts with MSI-X. This issue is also mentioned in 82574 data sheet(7.4.5 Clearing Interrupt Causes). However I couldn't explain odd interrupt behavior(interrupt moderation, MSI vs. MSI-X) of controller since the controller did not work as described in data sheet. > problem? Is there a patch floating around and I just haven't found > the right search terms? > > Thanks in advance, > Juli. > > PS: Yes, I know this is kind of a crappy bug report, sorry. I've had > a limited amount of time to investigate so far, and don't want to > delay reporting it until I am able to get more time with the > problematic hardware. _______________________________________________ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
