On Thu, Apr 7, 2016 at 9:33 AM, Ferruh Yigit <ferruh.yigit at intel.com> wrote:
> On 4/6/2016 9:22 PM, Jay Rolette wrote: > > Over a year ago, Neil pointed out that calling netif_rx() from > > kni_net_rx_normal() was a bug and could cause lockups. Here's the > comment: > > > > http://dpdk.org/ml/archives/dev/2015-March/015783.html > > > > Looking at the current code base, it is still calling netif_rx() instead > of > > netif_rx_ni() as suggested. > > > > Did that fall through the cracks or is there disagreement about whether > it > > was the right thing to do? > > > > Thanks, > > Jay > > > Hi Jay, > > Using netif_rx_ni() looks like correct thing to do. I will send a patch > for it. > > But we poll on this function, this means doing lots of > preempt_disable/enable(); which may have a negative effect on > performance. Although I did very brief test and did not observed any > performance degradation. > > It can be great if somebody out already using KNI do some performance > analysis with the patch. > > Another observation, for multiple kthread mode, the ksoftirq threads CPU > consumption removed when switched to netif_rx_ni(), I remember in mail > list somebody complained about ksoftirq CPU usage increase for this case. > Thanks Ferruh. We'll make that change in our local repo and run it through its paces. Jay
