[dpdk-dev] [PATCH] lib/librte_sched: Fix compile with gcc 4.3.4

Qiu, Michael michael.qiu at intel.com
Fri Nov 27 16:22:27 CET 2015


Sorry for not explaining clearly. 

For gcc version start from version 4.4, x86intrin.h will be include, and inside x86intrin.h, immintrin.h will be directly include without check AVX (as I know, AVX is not exist when gcc >= 4.4),so no AVX macro does not mean vector disable.

Only gcc < 4.4 and no macro AVX will disable vector.

This is my understanding, may be wrong :)

Thanks,
Michael

> 在 2015年11月27日,下午10:09,Ananyev, Konstantin <konstantin.ananyev at intel.com> 写道:
> 
> 
> 
>> -----Original Message-----
>> From: Qiu, Michael
>> Sent: Friday, November 27, 2015 2:02 PM
>> To: Ananyev, Konstantin
>> Cc: Thomas Monjalon; dev at dpdk.org
>> Subject: Re: [PATCH] lib/librte_sched: Fix compile with gcc 4.3.4
>> 
>> I just replied that Marco AVX only exist in gcc version < 4.4 , otherwise it will not exist.
> 
> If macro __AVX__ not defined, then 
> #if defined(__AVX__)
> would always be false and SCHED_VECTOR_ENABLE also wouldn't be defined.
> So still don't understand why that is a problem
> Konstantin
> 
>> 
>> What's your suggest will not work if gcc version greater than 4.3.
>> 
>> So still need to check gcc version. Any other solution?
>> 
>> Thanks,
>> Michael
>> 
>>> 在 2015年11月27日,下午8:34,Ananyev, Konstantin <konstantin.ananyev at intel.com> 写道:
>>> 
>>> 
>>>> -----Original Message-----
>>>> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Qiu, Michael
>>>> Sent: Friday, November 27, 2015 11:53 AM
>>>> To: Thomas Monjalon
>>>> Cc: dev at dpdk.org
>>>> Subject: Re: [dpdk-dev] [PATCH] lib/librte_sched: Fix compile with gcc 4.3.4
>>>> 
>>>> really?I don't think so.
>>>> 
>>>> AVX Marco only exist in the gcc version below 4.4,  I still need to check if below or beyond 4.4 am I right?
>>>> 
>>>> Thanks,
>>>> Michael
>>> 
>>> 
>>> If you look at lib/librte_eal/common/include/arch/x86/rte_vect.h, you'll see the code similar
>>> to one you are trying to put into rte_shed.c:
>>> 
>>> lib/librte_eal/common/include/arch/x86/rte_vect.h:
>>> ...
>>> #if (defined(__ICC) || (__GNUC__ == 4 &&  __GNUC_MINOR__ < 4))
>>> 
>>> #ifdef __SSE__
>>> #include <xmmintrin.h>
>>> #endif
>>> 
>>> #ifdef __SSE2__
>>> #include <emmintrin.h>
>>> #endif
>>> 
>>> #ifdef __SSE3__
>>> #include <tmmintrin.h>
>>> #endif
>>> 
>>> #if defined(__SSE4_2__) || defined(__SSE4_1__)
>>> #include <smmintrin.h>
>>> #endif
>>> 
>>> #if defined(__AVX__)
>>> #include <immintrin.h>
>>> #endif
>>> 
>>> #else
>>> 
>>> #include <x86intrin.h>
>>> 
>>> #endif
>>> ...
>>> 
>>> So I think you can do just like that:
>>> 
>>> #include <rte_vect.h>
>>> #if defined(__AVX__)
>>> #define SCHED_VECTOR_ENABLE
>>> #endif
>>> 
>>> inside rte_sched.c
>>> 
>>> Konstantin
>>> 
>>> 
>>>> 
>>>> 
>>>>> 在 2015年11月27日,下午5:01,Thomas Monjalon <thomas.monjalon at 6wind.com> 写道:
>>>>> 
>>>>> 2015-11-27 02:26, Qiu, Michael:
>>>>>>>> On 2015/11/27 5:29, Thomas Monjalon wrote:
>>>>>>>> 2015-11-26 18:49, Michael Qiu:
>>>>>>>> gcc 4.3.4 does not include "immintrin.h", and will post below error:
>>>>>>>>  lib/librte_sched/rte_sched.c:56:23: error:
>>>>>>>>  immintrin.h: No such file or directory
>>>>>>>> 
>>>>>>>> To avoid this issue, a gcc version check is need and a flag to indicate
>>>>>>>> vector ablility.
>>>>>>> [...]
>>>>>>>> +#if (defined(__ICC) || (__GNUC__ == 4 &&  __GNUC_MINOR__ < 4))
>>>>>>>> +
>>>>>>>> +#if defined(__AVX__)
>>>>>>>> #include <immintrin.h>
>>>>>>>> +#define SCHED_VECTOR_ENABLE
>>>>>>>> +#endif
>>>>>>>> +
>>>>>>>> +#else
>>>>>>>> +
>>>>>>>> +#include <x86intrin.h>
>>>>>>>> +#define SCHED_VECTOR_ENABLE
>>>>>>>> +
>>>>>>>> +#endif
>>>>>>> This kind of complication is managed by EAL.
>>>>>>> I think we should include rte_vect.h.
>>>>>> 
>>>>>> As I know here it needs a flag to identify whether the platform support
>>>>>> AVX, if not it will not use it, so I don't know if we could only simply
>>>>>> include rte_vect.h?
>>>>> 
>>>>> It's not exclusive.
>>>>> You can include rte_vect.h and check AVX to define SCHED_VECTOR_ENABLE.
>>>>> 


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