Re: [dpdk-dev] [PATCH] rte_delay_us can be replaced with user function

[Thomas Monjalon <thomas.monjalon@6wind.com>]

Hi,

I think this feature should enter in the release 16.11.
We just need to make sure it is implemented with the right API.
Do you have any comment about managing several builtin handlers?


2016-09-13 22:04, Thomas Monjalon:
> Hi,
> 
> Sorry for late review.
> This patch was in a summer hole :/
> 
> First a general comment: please check your patch with
> scripts/checkpatches.sh.
> In order to ease tracking of this patch, please increment the version
> when sending a new one in the same thread:
> 	git send-email -1 -v3 --annotate --to dev@dpdk.org \
> 	--in-reply-to 1469016644-6521-1-git-send-email-jozmarti@cisco.com
> 
> More comments below.
> 
> 2016-07-20 14:10, jozmarti@cisco.com:
> > +void rte_delay_us_callback_register(void (*userfunc)(unsigned))
> > +{
> > +    if (userfunc == NULL)
> > +        rte_delay_us = rte_delay_us_block;
> 
> Here you are creating an exception for rte_delay_us_block which is
> mapped as a NULL handler.
> What will happen if we need to provide more builtin handlers?
> I still think that rte_delay_us_block can be exported and initialized
> as the default handler. Other opinions are obviously welcome.
> 
> > +    else
> > +        rte_delay_us = userfunc;
> > +}
> > +
> > +static void __attribute__((constructor))
> > +rte_timer_init(void)
> > +{
> > +    /* set rte_delay_us_block as a delay function */
> > +    rte_delay_us_callback_register(NULL);
> > +}
> > diff --git a/lib/librte_eal/common/include/generic/rte_cycles.h b/lib/librte_eal/common/include/generic/rte_cycles.h
> > index 8cc21f2..7a45b58 100644
> > --- a/lib/librte_eal/common/include/generic/rte_cycles.h
> > +++ b/lib/librte_eal/common/include/generic/rte_cycles.h
> > @@ -182,13 +182,16 @@ rte_get_timer_hz(void)
> >  }
> >  
> >  /**
> > + *
> 
> useless newline
> 
> >   * Wait at least us microseconds.
> > + * This function can be replaced with user-defined function using
> > + * rte_delay_us_callback_register
> 
> I think you can use @see to point to rte_delay_us_callback_register.
> 
> >   *
> >   * @param us
> >   *   The number of microseconds to wait.
> >   */
> >  void
> > -rte_delay_us(unsigned us);
> > +(*rte_delay_us)(unsigned us);
> >  
> >  /**
> >   * Wait at least ms milliseconds.
> > @@ -202,4 +205,14 @@ rte_delay_ms(unsigned ms)
> >  	rte_delay_us(ms * 1000);
> >  }
> >  
> > +/**
> > + * Replace rte_delay_us with user defined function.
> > + *
> > + * @param userfunc
> > + *   User function which replaces rte_delay_us. NULL restores
> > + *   buildin block delay function.
> 
> buildin -> builtin ?
> 
> > + */
> > +void rte_delay_us_callback_register(void(*userfunc)(unsigned));
>