Re: [dpdk-dev] [PATCH v8 2/4] meson: add infra to support machine specific flags

From: Yongseok Koh <yskoh@mellanox.com>
To: Jerin Jacob Kollanukkaran <jerinj@marvell.com>
Cc: Pavan Nikhilesh Bhagavatula <pbhagavatula@marvell.com>,
	Thomas Monjalon <thomas@monjalon.net>, dev <dev@dpdk.org>,
	"jerinjacobk@gmail.com" <jerinjacobk@gmail.com>
Subject: Re: [dpdk-dev] [PATCH v8 2/4] meson: add infra to support machine specific flags
Date: Fri, 12 Apr 2019 07:47:53 +0000	[thread overview]
Message-ID: <32A9275B-097D-4C6F-B284-69364436D58B@mellanox.com> (raw)
In-Reply-To: <BYAPR18MB2424EDBAA3D91885C2D4FE80C8280@BYAPR18MB2424.namprd18.prod.outlook.com>

> On Apr 12, 2019, at 12:35 AM, Jerin Jacob Kollanukkaran <jerinj@marvell.com> wrote:
> 
> 
> 
>> -----Original Message-----
>> From: Yongseok Koh <yskoh@mellanox.com>
>> Sent: Friday, April 12, 2019 12:39 PM
>> To: Jerin Jacob Kollanukkaran <jerinj@marvell.com>
>> Cc: Pavan Nikhilesh Bhagavatula <pbhagavatula@marvell.com>; Thomas
>> Monjalon <thomas@monjalon.net>; dev <dev@dpdk.org>;
>> jerinjacobk@gmail.com
>> Subject: [EXT] Re: [dpdk-dev] [PATCH v8 2/4] meson: add infra to support
>> machine specific flags
>> 
>> 
>> 
>> One more issue.
>> With gcc7.2, crypto isn't enabled if -mcpu is set.
>> How about thunderx/octeon?
> 
> It is enabled when when mcpu=thunderxt88 is provided.
> In default case, it picks up -march=armv8-a+crc+crypto if mpcu is not matching. 
> So I don’t see any issue.
> 
>> Looks it should be like -mcpu=cortex-a72+crypto I'll take care of this in a
> 
> mcpu should be enough. Looks like like it a compiler bug, Is cortex-a72 available with out crypto?
> mcpu suppose to tune for specific cpu.

Yes, Mellanox BlueField is designed based on a72 and there are two variants in production.
One with crypto, the other w/o crypto. That might be the reason why -mcpu=cortex-a72
doesn't enable crypto by default.

>> separate patch.
>> Because I want to add a new option to control it.
>> The reason is a binary having crypto support can't be run on a cpu w/o crypto
>> extension, it is panicked.
>> And -mcpu=cortex-a72 includes 'crc' support by default.
> 
> I suggest to add config/arm/arm64_a72_linux_gcc, If we need to catch all this issue in
> cross compilation otherwise it will come only on native compilation on that specific board.
> Now the devtools/test-meson-builds.sh goes over all the config/arm/* on the native compilation 
> On arm64 board and x86. If you need set compiler test for a72 then please add the cross compile config.

Yes, I'm going to add config/arm/arm64_bluefield_linux_gcc soon. Patch is ready now.

Thanks,
Yongseok