Re: [dpdk-dev] [PATCH v5 2/2] net/hns3: refactor SVE code compile method

[fengchengwen <fengchengwen@huawei.com>]

On 2021/5/19 17:27, Ferruh Yigit wrote:
> On 5/19/2021 9:08 AM, David Marchand wrote:
>> On Tue, May 18, 2021 at 6:28 PM Ferruh Yigit <ferruh.yigit@intel.com> wrote:
>>>
>>> On 5/14/2021 3:12 PM, Honnappa Nagarahalli wrote:
>>>> <snip>
>>>>
>>>>>
>>>>> Currently, the SVE code is compiled only when -march supports SVE (e.g. '-
>>>>> march=armv8.2a+sve'), there maybe some problem[1] with this approach.
>>>>>
>>>>> The solution:
>>>>> a. If the minimum instruction set support SVE then compiles it.
>>>>> b. Else if the compiler support SVE then compiles it.
>>>>> c. Otherwise don't compile it.
>>>>>
>>>>> [1] https://mails.dpdk.org/archives/dev/2021-April/208189.html
>>>>>
>>>>> Fixes: 8c25b02b082a ("net/hns3: fix enabling SVE Rx/Tx")
>>>>> Fixes: 952ebacce4f2 ("net/hns3: support SVE Rx")
>>>>> Cc: stable@dpdk.org
>>>>>
>>>>> Signed-off-by: Chengwen Feng <fengchengwen@huawei.com>
>>>> Looks good to me.
>>>> Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
>>>>
>>>
>>> Applied to dpdk-next-net/main, thanks.
>>>
>>> (Only this patch, 2/2, applied, not whole set)
>>
>> UNH caught a build regression on next-net and I think this is due to this patch:
>> https://lab.dpdk.org/results/dashboard/tarballs/15259/
>>
> 
> Thanks David for heads up, yet it the reason of the error seems this patch, so I
> will drop it from the next-net.
> 
> 
> A few details from the error:
> 
> Default used compiler flag does not request SVE support, it is:
>   Compiler for C supports arguments -march=armv8.1-a+crc+crypto: YES
>   Compiler for C supports arguments -mcpu=thunderx2t99: YES
>   Message: Using machine args: ['-march=armv8.1-a+crc+crypto', '-mcpu=thunderx2t99']
> 
> It is detected that compiler can support SVE:
>   Compiler for C supports arguments -march=armv8.2-a+sve: YES
> 
> Because of the SVE support, driver tries to build 'hns3_rxtx_vec_sve.c' with SVE
> support, even user doesn't request SVE, this is the design in the patch, build
> command (stripped):
>   -march=armv8.1-a+crc+crypto -mcpu=thunderx2t99 -DCC_SVE_SUPPORT
> -march=armv8.2-a+sve ../drivers/net/hns3/hns3_rxtx_vec_sve.c
> 
> There are two errors:
> 
> 1) appended '-march=armv8.2-a+sve' compiler argument to build
> 'hns3_rxtx_vec_sve.c' is conflicting with rest of the command:
>   cc1: error: switch ‘-mcpu=armv8.1-a’ conflicts with ‘-march=armv8.2-a’ switch
> [-Werror]
> 
> 
> 2) SVE header is missing. When compiler supports the SVE, not sure why the
> header is missing:
>   ../drivers/net/hns3/hns3_rxtx_vec_sve.c:5:10: fatal error: arm_sve.h: No such
> file or directory
>     5 | #include <arm_sve.h>
>       |          ^~~~~~~~~~~
> 

Sorry to introduce compilation errors.
Already fix in new patch: [dpdk-dev] [PATCH v2] net/hns3: fix compile error with gcc8.3 and thunderx2
@David could you help test?


We also found compile error with gcc8.3 with arm64_kunpeng930_linux_gcc (-march=-march=armv8.2-a+crypto+sve):
  In file included from ../dpdk-next-net/lib/eal/common/eal_common_options.c:38:
  ../dpdk-next-net/lib/eal/arm/include/rte_vect.h:13:10: fatal error: arm_sve.h: No such file or directory
   #include <arm_sve.h>
          ^~~~~~~~~~~
  compilation terminated.
  [126/2250] Compiling C object lib/librte_net.a.p/net_rte_net_crc.c.o

the corresponding code:
  #ifdef __ARM_FEATURE_SVE
  #include <arm_sve.h>
  #endif

this is because gcc8.3 defined __ARM_FEATURE_SVE but it can't compile ACLE SVE code.
I will fix it later in 21.08

Best regards

> 
>> FAILED: drivers/net/hns3/libhns3_sve_lib.a.p/hns3_rxtx_vec_sve.c.o
>> ccache cc -Idrivers/net/hns3/libhns3_sve_lib.a.p -Idrivers/net/hns3
>> -I../drivers/net/hns3 -Ilib/ethdev -I../lib/ethdev -I. -I.. -Iconfig
>> -I../config -Ilib/eal/include -I../lib/eal/include
>> -Ilib/eal/linux/include -I../lib/eal/linux/include
>> -Ilib/eal/arm/include -I../lib/eal/arm/include -Ilib/eal/common
>> -I../lib/eal/common -Ilib/eal -I../lib/eal -Ilib/kvargs
>> -I../lib/kvargs -Ilib/metrics -I../lib/metrics -Ilib/telemetry
>> -I../lib/telemetry -Ilib/net -I../lib/net -Ilib/mbuf -I../lib/mbuf
>> -Ilib/mempool -I../lib/mempool -Ilib/ring -I../lib/ring -Ilib/meter
>> -I../lib/meter -fdiagnostics-color=always -pipe -D_FILE_OFFSET_BITS=64
>> -Wall -Winvalid-pch -Werror -O3 -include rte_config.h -Wextra
>> -Wcast-qual -Wdeprecated -Wformat -Wformat-nonliteral
>> -Wformat-security -Wmissing-declarations -Wmissing-prototypes
>> -Wnested-externs -Wold-style-definition -Wpointer-arith -Wsign-compare
>> -Wstrict-prototypes -Wundef -Wwrite-strings
>> -Wno-address-of-packed-member -Wno-packed-not-aligned
>> -Wno-missing-field-initializers -D_GNU_SOURCE -fPIC
>> -march=armv8.1-a+crc+crypto -mcpu=thunderx2t99
>> -DALLOW_EXPERIMENTAL_API -DALLOW_INTERNAL_API -Wno-format-truncation
>> -DCC_SVE_SUPPORT -march=armv8.2-a+sve -MD -MQ
>> drivers/net/hns3/libhns3_sve_lib.a.p/hns3_rxtx_vec_sve.c.o -MF
>> drivers/net/hns3/libhns3_sve_lib.a.p/hns3_rxtx_vec_sve.c.o.d -o
>> drivers/net/hns3/libhns3_sve_lib.a.p/hns3_rxtx_vec_sve.c.o -c
>> ../drivers/net/hns3/hns3_rxtx_vec_sve.c
>> cc1: error: switch ‘-mcpu=armv8.1-a’ conflicts with ‘-march=armv8.2-a’
>> switch [-Werror]
>> ../drivers/net/hns3/hns3_rxtx_vec_sve.c:5:10: fatal error: arm_sve.h:
>> No such file or directory
>>     5 | #include <arm_sve.h>
>>       |          ^~~~~~~~~~~
>> cc1: all warnings being treated as errors
>> compilation terminated.
>>
>>
>> I see a similar issue on my fc32, cross compiling with following gcc:
>> $ aarch64-linux-gnu-gcc --version
>> aarch64-linux-gnu-gcc (GNU Toolchain for the A-profile Architecture
>> 8.3-2019.03 (arm-rel-8.36)) 8.3.0
>> Copyright (C) 2018 Free Software Foundation, Inc.
>> This is free software; see the source for copying conditions.  There is NO
>> warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
>>
>> [74/503] Compiling C object
>> drivers/net/hns3/libhns3_sve_lib.a.p/hns3_rxtx_vec_sve.c.o
>> FAILED: drivers/net/hns3/libhns3_sve_lib.a.p/hns3_rxtx_vec_sve.c.o
>> aarch64-linux-gnu-gcc -Idrivers/net/hns3/libhns3_sve_lib.a.p
>> -Idrivers/net/hns3 -I../../dpdk/drivers/net/hns3 -Ilib/ethdev
>> -I../../dpdk/lib/ethdev -I. -I../../dpdk -Iconfig -I../../dpdk/config
>> -Ilib/eal/include -I../../dpdk/lib/eal/include -Ilib/eal/linux/include
>> -I../../dpdk/lib/eal/linux/include -Ilib/eal/arm/include
>> -I../../dpdk/lib/eal/arm/include -Ilib/eal/common
>> -I../../dpdk/lib/eal/common -Ilib/eal -I../../dpdk/lib/eal
>> -Ilib/kvargs -I../../dpdk/lib/kvargs -Ilib/metrics
>> -I../../dpdk/lib/metrics -Ilib/telemetry -I../../dpdk/lib/telemetry
>> -Ilib/net -I../../dpdk/lib/net -Ilib/mbuf -I../../dpdk/lib/mbuf
>> -Ilib/mempool -I../../dpdk/lib/mempool -Ilib/ring
>> -I../../dpdk/lib/ring -Ilib/meter -I../../dpdk/lib/meter
>> -fdiagnostics-color=always -pipe -D_FILE_OFFSET_BITS=64 -Wall
>> -Winvalid-pch -Werror -O2 -g -include rte_config.h -Wextra -Wcast-qual
>> -Wdeprecated -Wformat -Wformat-nonliteral -Wformat-security
>> -Wmissing-declarations -Wmissing-prototypes -Wnested-externs
>> -Wold-style-definition -Wpointer-arith -Wsign-compare
>> -Wstrict-prototypes -Wundef -Wwrite-strings -Wno-packed-not-aligned
>> -Wno-missing-field-initializers -D_GNU_SOURCE -fPIC -march=armv8-a+crc
>> -DALLOW_EXPERIMENTAL_API -DALLOW_INTERNAL_API -Wno-format-truncation
>> -DCC_SVE_SUPPORT -march=armv8.2-a+sve -MD -MQ
>> drivers/net/hns3/libhns3_sve_lib.a.p/hns3_rxtx_vec_sve.c.o -MF
>> drivers/net/hns3/libhns3_sve_lib.a.p/hns3_rxtx_vec_sve.c.o.d -o
>> drivers/net/hns3/libhns3_sve_lib.a.p/hns3_rxtx_vec_sve.c.o -c
>> ../../dpdk/drivers/net/hns3/hns3_rxtx_vec_sve.c
>> ../../dpdk/drivers/net/hns3/hns3_rxtx_vec_sve.c:5:10: fatal error:
>> arm_sve.h: No such file or directory
>>  #include <arm_sve.h>
>>           ^~~~~~~~~~~
>> compilation terminated.
>>
>>
> 
> 
> .
>