Re: [dpdk-stable] [PATCH] net/softnic: fix pipeline time calculation

["Wang, Xiao W" <xiao.w.wang@intel.com>]

> -----Original Message-----
> From: Singh, Jasvinder
> Sent: Friday, May 31, 2019 10:46 PM
> To: Wang, Xiao W <xiao.w.wang@intel.com>
> Cc: dev@dpdk.org; Dumitrescu, Cristian <cristian.dumitrescu@intel.com>;
> stable@dpdk.org
> Subject: RE: [PATCH] net/softnic: fix pipeline time calculation
> 
> 
> 
> > -----Original Message-----
> > From: Wang, Xiao W
> > Sent: Wednesday, May 15, 2019 2:59 PM
> > To: Singh, Jasvinder <jasvinder.singh@intel.com>
> > Cc: dev@dpdk.org; Dumitrescu, Cristian <cristian.dumitrescu@intel.com>;
> > Wang, Xiao W <xiao.w.wang@intel.com>; stable@dpdk.org
> > Subject: [PATCH] net/softnic: fix pipeline time calculation
> >
> > When a new pipeline is added to a thread, the "time_next_min" value may
> > need update, otherwise this pipeline won't get served timely.
> >
> > Fixes: 70709c78fda6 ("net/softnic: add command to enable/disable pipeline")
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Xiao Wang <xiao.w.wang@intel.com>
> > ---
> >  drivers/net/softnic/rte_eth_softnic_thread.c | 6 ++++++
> >  1 file changed, 6 insertions(+)
> >
> > diff --git a/drivers/net/softnic/rte_eth_softnic_thread.c
> > b/drivers/net/softnic/rte_eth_softnic_thread.c
> > index 855408e98..2b482117d 100644
> > --- a/drivers/net/softnic/rte_eth_softnic_thread.c
> > +++ b/drivers/net/softnic/rte_eth_softnic_thread.c
> > @@ -337,6 +337,9 @@ softnic_thread_pipeline_enable(struct
> pmd_internals
> > *softnic,
> >  		tdp->timer_period = (rte_get_tsc_hz() * p->timer_period_ms)
> /
> > 1000;
> >  		tdp->time_next = rte_get_tsc_cycles() + tdp->timer_period;
> >
> > +		if (tdp->time_next < td->time_next_min)
> > +			td->time_next_min = tdp->time_next;
> > +
> >  		td->n_pipelines++;
> >
> >  		/* Pipeline */
> > @@ -522,6 +525,9 @@ thread_msg_handle_pipeline_enable(struct
> > softnic_thread_data *t,
> >  		(rte_get_tsc_hz() * req->pipeline_enable.timer_period_ms) /
> > 1000;
> >  	p->time_next = rte_get_tsc_cycles() + p->timer_period;
> >
> > +	if (p->time_next < t->time_next_min)
> > +		t->time_next_min = p->time_next;
> > +
> >  	t->n_pipelines++;
> >
> >  	/* Response */
> > --
> > 2.15.1
> 
> 
> Hi Wang,
> 
> Timer values for pipelines and thread level message handlers are already
> adjusted in runtime function rte_pmd_softnic_run_internal(). In runtime
> function, the values of t->time_next_min is updated as well. IMO, above
> changes not needed. Could you help with the case where timer adjustments in
> runtime not working?

Hi Jasvinder,

the values of t->time_next_min is updated only when the pipeline message and thread message get handled, but not when the pipeline is added to that thread. E.g. when a thread t->time_next_min is ~100ms later, and a new pipeline is added to that thread with timer_period_ms parameter set to 10ms, then this pipeline's control message will not be served until 100ms later.

BRs,
Xiao

> 
> Thanks,
> Jasvinder
>