Messages in this thread | | | From | Sudip Mukherjee <> | Date | Fri, 19 Jul 2019 16:53:28 +0100 | Subject | Re: regression with napi/softirq ? |
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On Thu, Jul 18, 2019 at 4:08 PM Eric Dumazet <eric.dumazet@gmail.com> wrote: > > > > On 7/18/19 2:55 PM, Sudip Mukherjee wrote: > > > Thanks Eric. But there is no improvement in delay between > > softirq_raise and softirq_entry with this change. > > But moving to a later kernel (linus master branch? ) like Thomas has > > said in the other mail might be difficult atm. I can definitely > > move to v4.14.133 if that helps. Thomas ? > > If you are tracking max latency then I guess you have to tweak SOFTIRQ_NOW_MASK > to include NET_RX_SOFTIRQ > > The patch I gave earlier would only lower the probability of events, not completely get rid of them. > > > > diff --git a/kernel/softirq.c b/kernel/softirq.c > index 0427a86743a46b7e1891f7b6c1ff585a8a1695f5..302046dd8d7e6740e466c422954f22565fe19e69 100644 > --- a/kernel/softirq.c > +++ b/kernel/softirq.c > @@ -81,7 +81,7 @@ static void wakeup_softirqd(void) > * right now. Let ksoftirqd handle this at its own rate, to get fairness, > * unless we're doing some of the synchronous softirqs. > */ > -#define SOFTIRQ_NOW_MASK ((1 << HI_SOFTIRQ) | (1 << TASKLET_SOFTIRQ)) > +#define SOFTIRQ_NOW_MASK ((1 << HI_SOFTIRQ) | (1 << TASKLET_SOFTIRQ) | (1 << NET_RX_SOFTIRQ)) > static bool ksoftirqd_running(unsigned long pending) > { > struct task_struct *tsk = __this_cpu_read(ksoftirqd);
Thanks Eric, this looks better than the hack that tglx gave. :) Though the hack was good for testing.
But my original problem was a drop is network packets and till now I was thinking that the delay in processing the softirq is causing that. But with the hack tglx has given the latency has decreased but my problem is still there. So, I am looking into it again now.
Thanks again for the patch.
-- Regards Sudip
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