Re: [dpdk-dev] Use WFE for spinlock and ring

[Stephen Hemminger <stephen@networkplumber.org>]

On Sun, 25 Apr 2021 05:56:51 +0000
Ruifeng Wang <ruifeng.wang@arm.com> wrote:

> The rte_wait_until_equal_xxx APIs abstract the functionality of 'polling
> for a memory location to become equal to a given value'[1].
> 
> Use the API for the rte spinlock and ring implementations.
> With the wait until equal APIs being stable, changes will not impact ABI.
> 
> [1] http://patches.dpdk.org/cover/62703/
> 
> v3:
> Series rebased. (David)
> 
> Gavin Hu (1):
>   spinlock: use wfe to reduce contention on aarch64
> 
> Ruifeng Wang (1):
>   ring: use wfe to wait for ring tail update on aarch64
> 
>  lib/eal/include/generic/rte_spinlock.h | 4 ++--
>  lib/ring/rte_ring_c11_pvt.h            | 4 ++--
>  lib/ring/rte_ring_generic_pvt.h        | 3 +--
>  3 files changed, 5 insertions(+), 6 deletions(-)
> 

Other places that should use WFE:

rte_mcslock.h:rte_mcslock_lock()
rte_mcslock_unlock:rte_mcslock_unlock()

rte_pflock.h:rte_pflock_lock()
rte_rwlock.h:rte_rwlock_read_lock()
rte_rwlock.h:rte_rwlock_write_lock()


You should also introduce rte_wait_while_XXX variants to handle some
of these cases.