Re: [dpdk-dev] [PATCH v2 1/2] eal: add 128-bit cmpset (x86-64 only)

[Gavin Hu (Arm Technology China)]

> -----Original Message-----
> From: Eads, Gage <gage.e...@intel.com>
> Sent: Thursday, January 17, 2019 11:14 PM
> To: Gavin Hu (Arm Technology China) <gavin...@arm.com>;
> dev@dpdk.org
> Cc: olivier.m...@6wind.com; arybche...@solarflare.com; Richardson,
> Bruce <bruce.richard...@intel.com>; Ananyev, Konstantin
> <konstantin.anan...@intel.com>; Honnappa Nagarahalli
> <honnappa.nagaraha...@arm.com>
> Subject: RE: [dpdk-dev] [PATCH v2 1/2] eal: add 128-bit cmpset (x86-64
> only)
> 
> 
> 
> > -----Original Message-----
> > From: Gavin Hu (Arm Technology China) [mailto:gavin...@arm.com]
> > Sent: Thursday, January 17, 2019 2:49 AM
> > To: Eads, Gage <gage.e...@intel.com>; dev@dpdk.org
> > Cc: olivier.m...@6wind.com; arybche...@solarflare.com; Richardson,
> Bruce
> > <bruce.richard...@intel.com>; Ananyev, Konstantin
> > <konstantin.anan...@intel.com>; Honnappa Nagarahalli
> > <honnappa.nagaraha...@arm.com>
> > Subject: RE: [dpdk-dev] [PATCH v2 1/2] eal: add 128-bit cmpset (x86-64
> only)
> >
> >
> >
> > > -----Original Message-----
> > > From: dev <dev-boun...@dpdk.org> On Behalf Of Gage Eads
> > > Sent: Wednesday, January 16, 2019 6:33 AM
> > > To: dev@dpdk.org
> > > Cc: olivier.m...@6wind.com; arybche...@solarflare.com;
> > > bruce.richard...@intel.com; konstantin.anan...@intel.com
> > > Subject: [dpdk-dev] [PATCH v2 1/2] eal: add 128-bit cmpset (x86-64
> > > only)
> > >
> > > This operation can be used for non-blocking algorithms, such as a
> > > non-blocking stack or ring.
> > >
> > > Signed-off-by: Gage Eads <gage.e...@intel.com>
> > > ---
> > >  .../common/include/arch/x86/rte_atomic_64.h        | 22
> > > ++++++++++++++++++++++
> > >  1 file changed, 22 insertions(+)
> > >
> > > diff --git a/lib/librte_eal/common/include/arch/x86/rte_atomic_64.h
> > > b/lib/librte_eal/common/include/arch/x86/rte_atomic_64.h
> > > index fd2ec9c53..34c2addf8 100644
> > > --- a/lib/librte_eal/common/include/arch/x86/rte_atomic_64.h
> > > +++ b/lib/librte_eal/common/include/arch/x86/rte_atomic_64.h
> > > @@ -34,6 +34,7 @@
> > >  /*
> > >   * Inspired from FreeBSD src/sys/amd64/include/atomic.h
> > >   * Copyright (c) 1998 Doug Rabson
> > > + * Copyright (c) 2019 Intel Corporation
> > >   * All rights reserved.
> > >   */
> > >
> > > @@ -208,4 +209,25 @@ static inline void
> > > rte_atomic64_clear(rte_atomic64_t *v)  }  #endif
> > >
> > > +static inline int
> > > +rte_atomic128_cmpset(volatile uint64_t *dst, uint64_t *exp, uint64_t
> > > *src)
> > > +{
> > > +uint8_t res;
> > > +
> > > +asm volatile (
> > > +      MPLOCKED
> > > +      "cmpxchg16b %[dst];"
> > > +      " sete %[res]"
> > > +      : [dst] "=m" (*dst),
> > > +[res] "=r" (res)
> > > +      : "c" (src[1]),
> > > +"b" (src[0]),
> > > +"m" (*dst),
> > > +"d" (exp[1]),
> > > +"a" (exp[0])
> > > +      : "memory");
> > > +
> > > +return res;
> > > +}
> > > +
> >
> > CONFIG_RTE_DRIVER_MEMPOOL_NB_STACK=y can't coexist with
> > RTE_FORCE_INTRINSICS=y, this should be explicitly described somewhere
> in the
> > configuration and documentations.
> >
> 
> This patch places rte_atomic128_cmpset() outside of the
> RTE_FORCE_INTRINSICS ifndef, and this file is included regardless of that
> config flag, so it's compiled either way.
> 

Acked-by: Gavin Hu <gavin...@arm.com>

> > >  #endif /* _RTE_ATOMIC_X86_64_H_ */
> > > --
> > > 2.13.6
> >