[dpdk-dev] [PATCH v6] eal/x86: add 128-bit atomic compare exchange

[Eads, Gage]

> -----Original Message-----
> From: Eads, Gage
> Sent: Thursday, April 4, 2019 7:23 AM
> To: 'Thomas Monjalon' <thomas at monjalon.net>; Yigit, Ferruh
> <ferruh.yigit at intel.com>
> Cc: Shahaf Shuler <shahafs at mellanox.com>; Matan Azrad
> <matan at mellanox.com>; Yongseok Koh <yskoh at mellanox.com>;
> dev at dpdk.org; olivier.matz at 6wind.com; arybchenko at solarflare.com;
> Richardson, Bruce <bruce.richardson at intel.com>; Ananyev, Konstantin
> <konstantin.ananyev at intel.com>; gavin.hu at arm.com;
> Honnappa.Nagarahalli at arm.com; nd at arm.com;
> chaozhu at linux.vnet.ibm.com; jerinj at marvell.com;
> hemant.agrawal at nxp.com
> Subject: RE: [dpdk-dev] [PATCH v6] eal/x86: add 128-bit atomic compare
> exchange
> 
> > -----Original Message-----
> > From: Thomas Monjalon [mailto:thomas at monjalon.net]
> > Sent: Thursday, April 4, 2019 7:18 AM
> > To: Eads, Gage <gage.eads at intel.com>; Yigit, Ferruh
> > <ferruh.yigit at intel.com>
> > Cc: Shahaf Shuler <shahafs at mellanox.com>; Matan Azrad
> > <matan at mellanox.com>; Yongseok Koh <yskoh at mellanox.com>;
> dev at dpdk.org;
> > olivier.matz at 6wind.com; arybchenko at solarflare.com; Richardson, Bruce
> > <bruce.richardson at intel.com>; Ananyev, Konstantin
> > <konstantin.ananyev at intel.com>; gavin.hu at arm.com;
> > Honnappa.Nagarahalli at arm.com; nd at arm.com;
> chaozhu at linux.vnet.ibm.com;
> > jerinj at marvell.com; hemant.agrawal at nxp.com
> > Subject: Re: [dpdk-dev] [PATCH v6] eal/x86: add 128-bit atomic compare
> > exchange
> >
> > 04/04/2019 14:14, Eads, Gage:
> > > From: Thomas Monjalon [mailto:thomas at monjalon.net]
> > > > 04/04/2019 14:08, Thomas Monjalon:
> > > > > 04/04/2019 13:47, Ferruh Yigit:
> > > > > > .../dpdk/x86_64-native-linuxapp-
> gcc/include/rte_atomic_64.h:223:3:
> > > > > > error: ISO C does not support ‘__int128’ types
> > > > > > [-Werror=pedantic]
> > > > >
> > > > > We can try this kind of workaround (disable pedantic locally):
> > > > >
> > > >
> >
> https://github.com/HowardHinnant/date/pull/38/commits/177032852d5b46
> > > > 14
> > > > > 112ca1ab3ef42d6b41824816
> > > >
> > > > Or better:
> > > > __extension__ typedef __int128 int128;
> > > >
> > >
> > > Taking that one step further -- RTE_STD_C11 evaluates to
> > > __extension__
> > (when the STD C version is sufficiently old).
> >
> > I don't think __int128 is part of C11. Is it?
> 
> You're right, this is a compiler extension. Using '__extension__' makes more
> sense.

FYI, __int128 was added in GCC 4.6 (and DPDK's minimum version is currently 4.9).