Re: [dpdk-dev] [PATCH 2/2] config: allow overriding some build defaults

[Bruce Richardson <bruce.richardson@intel.com>]

On Tue, Sep 01, 2020 at 06:07:56AM +0000, Hemant Agrawal wrote:
> HI Bruce,
> 	Will you please also add similar command examples in docs so that it becomes easy for the developers to use meson?
> 
> Regards,
> Hemant
> 

I'll add a note in somewhere, but this is probably not something that we
want to be advertising too much. We are trying to move away from build-time
config so we want the defaults to be sane and try and avoid developers
asking the end-user to compile up DPDK with magic flags. That said, it
should be possible, and documented. :-)

/Bruce

> -----Original Message-----
> From: dev <dev-bounces@dpdk.org> On Behalf Of Ma, LihongX
> Sent: Tuesday, September 1, 2020 10:48 AM
> To: Richardson, Bruce <bruce.richardson@intel.com>; dev@dpdk.org
> Cc: bluca@debian.org; Richardson, Bruce <bruce.richardson@intel.com>
> Subject: Re: [dpdk-dev] [PATCH 2/2] config: allow overriding some build defaults
> 
> Tested-by: lihongx Ma<lihongx.ma@intel.com> Before apply this patchset, set config like DRTE_LIBRTE_I40E_QUEUE_NUM_PER_VM=8 will failed, After apply this patchset, the the meson build can work find.
> Cmd like below:
> meson -Denable_kmods=True -Dlibdir=lib --default-library=static -Dexamples=vmdq_dcb -Dc_args='-DRTE_LIBRTE_I40E_QUEUE_NUM_PER_VM=8' config-test1 ninja -C config-test1
> 
> Regards,
> Ma,lihong
> 
> > -----Original Message-----
> > From: dev <dev-bounces@dpdk.org> On Behalf Of Bruce Richardson
> > Sent: Tuesday, August 25, 2020 7:45 PM
> > To: dev@dpdk.org
> > Cc: bluca@debian.org; Richardson, Bruce <bruce.richardson@intel.com>
> > Subject: [dpdk-dev] [PATCH 2/2] config: allow overriding some build 
> > defaults
> > 
> > In case a developer uses CFLAGS to set different default values for 
> > the defines in the rte_config.h file, use #ifndef / #endif guards 
> > around the setting of those values. For those lines just "defining" a 
> > macro without assigning it a value to be used by code, drop the value 
> > argument (where
> > possible) to make it clearer that that is what is happening, since 
> > those don't need the #ifdef guard.
> > 
> > Signed-off-by: Bruce Richardson <bruce.richardson@intel.com>
> > ---
> >  config/rte_config.h | 110 
> > +++++++++++++++++++++++++++++++++++++++-----
> >  1 file changed, 99 insertions(+), 11 deletions(-)
> > 
> > diff --git a/config/rte_config.h b/config/rte_config.h index
>