Hi Konstantin,
> -----Original Message-----
> From: Ananyev, Konstantin <konstantin.anan...@intel.com>
> Sent: Friday, April 24, 2020 9:24 PM
> To: Gavin Hu <gavin...@arm.com>; dev@dpdk.org
> Cc: nd <n...@arm.com>; david.march...@redhat.com;
> tho...@monjalon.net; jer...@marvell.com; Honnappa Nagarahalli
> <honnappa.nagaraha...@arm.com>; Ruifeng Wang
> <ruifeng.w...@arm.com>; Phil Yang <phil.y...@arm.com>; Joyce Kong
> <joyce.k...@arm.com>
> Subject: RE: [dpdk-dev] [PATCH v1 2/2] ring: use wfe to wait for ring tail
> update on aarch64
>
>
> >
> > Instead of polling for tail to be updated, use wfe instruction.
> >
> > Signed-off-by: Gavin Hu <gavin...@arm.com>
> > Reviewed-by: Ruifeng Wang <ruifeng.w...@arm.com>
> > Reviewed-by: Steve Capper <steve.cap...@arm.com>
> > Reviewed-by: Ola Liljedahl <ola.liljed...@arm.com>
> > Reviewed-by: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com>
> > ---
> > lib/librte_ring/rte_ring_c11_mem.h | 4 ++--
> > lib/librte_ring/rte_ring_generic.h | 3 +--
> > 2 files changed, 3 insertions(+), 4 deletions(-)
> >
> > diff --git a/lib/librte_ring/rte_ring_c11_mem.h
> b/lib/librte_ring/rte_ring_c11_mem.h
> > index 0fb73a337..764d8f186 100644
> > --- a/lib/librte_ring/rte_ring_c11_mem.h
> > +++ b/lib/librte_ring/rte_ring_c11_mem.h
> > @@ -2,6 +2,7 @@
> > *
> > * Copyright (c) 2017,2018 HXT-semitech Corporation.
> > * Copyright (c) 2007-2009 Kip Macy km...@freebsd.org
> > + * Copyright (c) 2019 Arm Limited
> > * All rights reserved.
> > * Derived from FreeBSD's bufring.h
> > * Used as BSD-3 Licensed with permission from Kip Macy.
> > @@ -21,8 +22,7 @@ update_tail(struct rte_ring_headtail *ht, uint32_t
> old_val, uint32_t new_val,
> > * we need to wait for them to complete
> > */
> > if (!single)
> > - while (unlikely(ht->tail != old_val))
> > - rte_pause();
> > + rte_wait_until_equal_relaxed_32(&ht->tail, old_val);
> >
> > __atomic_store_n(&ht->tail, new_val, __ATOMIC_RELEASE);
> > }
> > diff --git a/lib/librte_ring/rte_ring_generic.h
> b/lib/librte_ring/rte_ring_generic.h
> > index 953cdbbd5..682852783 100644
> > --- a/lib/librte_ring/rte_ring_generic.h
> > +++ b/lib/librte_ring/rte_ring_generic.h
> > @@ -23,8 +23,7 @@ update_tail(struct rte_ring_headtail *ht, uint32_t
> old_val, uint32_t new_val,
> > * we need to wait for them to complete
> > */
> > if (!single)
> > - while (unlikely(ht->tail != old_val))
> > - rte_pause();
> > + rte_wait_until_equal_relaxed_32(&ht->tail, old_val);
>
> ./lib/librte_ring/rte_ring_generic.h:26:3: error: implicit declaration of
> function 'rte_wait_until_equal_relaxed_32'; did you mean
> 'rte_wait_until_equal_32'? [-Werror=implicit-function-declaration]
> rte_wait_until_equal_relaxed_32(&ht->tail, old_val);
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Sorry for the leakage, fixed in v2.
>
> BTW, after patch #1 compilation fails also:
> ../lib/librte_eal/x86/include/rte_spinlock.h:125:24: error: pointer targets in
> passing argument 1 of 'rte_try_tm' differ in signedness [-Werror=pointer-
> sign]
> if (likely(rte_try_tm(&sl->locked)))
Fixed in v2, thanks!
> ^
>
>
>
> >
> > ht->tail = new_val;
> > }
> > --
> > 2.17.1
