Re: [dpdk-dev] [dpdk-stable] [PATCH] net/dpaa2: fix build error about timesync functions

[Ferruh Yigit <ferruh.yigit@intel.com>]

On 9/17/2020 12:50 PM, Hemant Agrawal wrote:
> 
> On 9/17/2020 5:08 PM, Ferruh Yigit wrote:
>> On 9/17/2020 3:03 AM, Di, ChenxuX wrote:
>>> Hi,
>>>
>>>> -----Original Message-----
>>>> From: Ferruh Yigit <ferruh.yigit@intel.com>
>>>> Sent: Wednesday, September 16, 2020 11:29 PM
>>>> To: Di, ChenxuX <chenxux.di@intel.com>; hemant.agrawal@nxp.com
>>>> Cc: sachin.saxena@nxp.com; stable@dpdk.org; dev@dpdk.org; Richardson,
>>>> Bruce <bruce.richardson@intel.com>
>>>> Subject: Re: [dpdk-stable] [PATCH] net/dpaa2: fix build error about 
>>>> timesync
>>>> functions
>>>>
>>>> On 9/15/2020 3:40 AM, Chenxu Di wrote:
>>>>> When the build option has '-DRTE_LIBRTE_IEEE1588=1', the announce of
>>>>> timesync functions will be build.
>>>>> However the dpdk_conf doesn't hav RTE_LIBRTE_IEEE1588 so that the file
>>>>> dpaa2_ptp.c will not be build.
>>>>> It cause the build error.
>>>>> This patch fixes it by adding set for dpdk_conf.
>>>>>
>>>>> Fixes: 184c39d16568 ("net/dpaa2: add DPRTC sub-module")
>>>>> Cc: stable@dpdk.org
>>>>>
>>>>> Signed-off-by: Chenxu Di <chenxux.di@intel.com>
>>>>> ---
>>>>>    drivers/net/dpaa2/meson.build | 4 ++++
>>>>>    1 file changed, 4 insertions(+)
>>>>>
>>>>> diff --git a/drivers/net/dpaa2/meson.build
>>>>> b/drivers/net/dpaa2/meson.build index 6dd0eb274..d9aadfdae 100644
>>>>> --- a/drivers/net/dpaa2/meson.build
>>>>> +++ b/drivers/net/dpaa2/meson.build
>>>>> @@ -17,6 +17,10 @@ sources = files('base/dpaa2_hw_dpni.c',
>>>>>            'mc/dpdmux.c',
>>>>>            'mc/dpni.c')
>>>>>
>>>>> +if '-DRTE_LIBRTE_IEEE1588=1' in get_option('c_args')
>>>>
>>>> The "RTE_LIBRTE_IEEE1588=1" can fail,
>>>> all places looking for "#ifdef RTE_LIBRTE_IEEE1588", so a "-Dc_args=-
>>>> DRTE_LIBRTE_IEEE1588" is more likely, but why not "-Dc_args=-
>>>> DRTE_LIBRTE_IEEE1588=666"
>>>>
>>>
>>> Yes, I will change it
>>>
>>>>> + dpdk_conf.set('RTE_LIBRTE_IEEE1588', 1) endif
>>>>> +
>>>>>    if dpdk_conf.has('RTE_LIBRTE_IEEE1588')
>>>>>        sources += files('mc/dprtc.c')
>>>>>        sources += files('dpaa2_ptp.c')
>>>>>
>>>>
>>>> Can't we just remove the conditional build:
>>>>
>>>>    -if dpdk_conf.has('RTE_LIBRTE_IEEE1588')
>>>>    -       sources += files('mc/dprtc.c')
>>>>    -       sources += files('dpaa2_ptp.c')
>>>>    -endif
>>>>    +sources += files('mc/dprtc.c')
>>>>    +sources += files('dpaa2_ptp.c')
>>>
>>> The announce of timesync functions are in the #define 
>>> DRTE_LIBRTE_IEEE1588
>>> While the define of the functions are in the file 'dpaa2_ptp.c'.
>>> So they should be both build or not build by whether the build option 
>>> -DRTE_LIBRTE_IEEE1588=1 or not.
>>> So it seems not a good idea that remove the conditional.
>>>
>>
>> timesyncs_* dev_ops functions defined but not used is not big problem, 
>> only can increase the library size.
>>
>> I believe more concern is on:
>> 'RTE_PMD_REGISTER_DPAA2_OBJECT(dprtc, rte_dpaa2_dprtc_obj);'
>> which looks like register function to run in constructor when 
>> 'dpaa2_ptp.c' is compiled, but not sure affect of it.
>> It can be possible to wrap that call with 'RTE_LIBRTE_IEEE1588' ifdef, 
>> that should work.
>>
>> It is preferred to remove the compile time flag instead of finding 
>> ways to make it work.
>>
>> Let's wait for the dpaa2 maintainers' response, perhaps they can come 
>> with a smart way to remove the compile time flag.
> 
> Hi Ferruh,
> 
>     enabling  IEEE1588 causes some performance drop in the dpaa2 
> performance. That is the reason, we have kept this code in compile time 
> flag.
> 
> 
> However, we will work in future to make it run-time configurable but 
> that will require some code restructuring and it will be a moderate size 
> work.
> 

OK, thanks Hemant.

At least can it be possible to remove it from the build files, what do 
you think about wrapping those two files (or their relevant parts) with 
'RTE_LIBRTE_IEEE1588' ifdef and remove the checks from meson file?