Re: [dpdk-dev] [PATCH v2 4/7] rte_sched: don't clear statistics when read

["Dumitrescu, Cristian" <cristian.dumitrescu@intel.com>]

> -----Original Message-----
> From: Thomas Monjalon [mailto:thomas.monjalon@6wind.com]
> Sent: Friday, February 20, 2015 9:01 PM
> To: Dumitrescu, Cristian
> Cc: dev@dpdk.org; Stephen Hemminger
> Subject: Re: [dpdk-dev] [PATCH v2 4/7] rte_sched: don't clear statistics when
> read
> 
> 2015-02-20 20:23, Dumitrescu, Cristian:
> > From: Stephen Hemminger [mailto:stephen@networkplumber.org]
> > > On Fri, 20 Feb 2015 18:32:03 +0000
> > > "Dumitrescu, Cristian" <cristian.dumitrescu@intel.com> wrote:
> > >
> > > > Stephen, I suggest adding a new build-time configuration option for the
> > > > librte_sched library in config/common_* files:
> > > > CONFIG_RTE_SCHED_STATS_CLEAR_ON_READ.
> > >
> > > Build time config options do not work for distributions.
> >
> > Why?
> >
> > This does not affect the API, as the new API functions are always compiled
> > in, and the prototypes are not changed, and no data structures are
> affected.
> 
> Behaviour is an important part of the API. Think comments as part of the API.

Makes sense.

> 
> > This only changes the behavior of certain functions, so that user can
> > select which mode it needs.
> 
> When user doesn't or cannot rebuild, he has no choice.
> 
> > It also preserves backward compatibility.
> >
> > We have so many compilation options in config file, why is this one
> different?
> 
> We must remove and avoid build-time options.
> The only ones which might be acceptable are the ones which allow more
> performance by disabling some features.

Agree.
Stephen, how about a run-time solution (I agree it would be much better, why did I not consider this in the first place?) of adding a new bool parameter in struct rte_sched_port_params: clear_stats_on_reset?
Both stats read function get the port handle (struct rte_sched_port *) as parameter, so there should be no ripple effect to propagate this flag.

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I did earlier, this is still work in progress unfortunately.

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