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

[Ferruh Yigit]

On 5/19/2021 9:08 AM, David Marchand wrote:
> On Tue, May 18, 2021 at 6:28 PM Ferruh Yigit <ferruh.yigit at 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 at dpdk.org
>>>>
>>>> Signed-off-by: Chengwen Feng <fengchengwen at huawei.com>
>>> Looks good to me.
>>> Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli at 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>
      |          ^~~~~~~~~~~


> 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.
> 
>