Re: [Linuxarm] [PATCH RFC v4 0/3] Some optimization for lockless qdisc

[Vladimir Oltean]

On Thu, May 20, 2021 at 04:46:52PM +0300, Vladimir Oltean wrote:
> Hi Yunsheng,
> 
> On Thu, May 20, 2021 at 05:45:14PM +0800, Yunsheng Lin wrote:
> > On 2021/5/20 17:27, Yunsheng Lin wrote:
> > > Patch 1: remove unnecessary seqcount operation.
> > > Patch 2: implement TCQ_F_CAN_BYPASS.
> > > Patch 3: remove qdisc->empty.
> > > 
> > > RFC v4: Use STATE_MISSED and STATE_DRAINING to indicate non-empty
> > >         qdisc, and add patch 1 and 3.
> > 
> > @Vladimir, Ahmad
> > It would be good to run your testcase to see if there are any
> > out of order for this version, because this version has used
> > STATE_MISSED and STATE_DRAINING to indicate non-empty qdisc,
> > thanks.
> > 
> > It is based on newest net branch with qdisc stuck patchset.
> > 
> > Some performance data as below:
> > 
> > pktgen + dummy netdev:
> >  threads  without+this_patch   with+this_patch      delta
> >     1       2.60Mpps            3.18Mpps             +22%
> >     2       3.84Mpps            5.72Mpps             +48%
> >     4       5.52Mpps            5.52Mpps             +0.0%
> >     8       2.77Mpps            2.81Mpps             +1.4%
> >    16       2.24Mpps            2.29Mpps             +2.2%
> > 
> > IP forward testing: 1.05Mpps increases to 1.15Mpps
> 
> I will start the regression test with the flexcan driver on LS1028A and
> let you know tomorrow or so if there is any TX reordering issue.

14 million CAN frames later, I did not observe any TX reordering at all.