[dpdk-dev] [PATCH v2 2/4] eventdev: use c11 atomics for lcore timer armed flag

[Carrillo, Erik G]

> -----Original Message-----
> From: Phil Yang <phil.yang at arm.com>
> Sent: Thursday, July 2, 2020 12:27 AM
> To: Carrillo, Erik G <erik.g.carrillo at intel.com>; dev at dpdk.org
> Cc: jerinj at marvell.com; Honnappa.Nagarahalli at arm.com;
> drc at linux.vnet.ibm.com; Ruifeng.Wang at arm.com;
> Dharmik.Thakkar at arm.com; nd at arm.com
> Subject: [PATCH v2 2/4] eventdev: use c11 atomics for lcore timer armed flag
> 
> The in_use flag is a per core variable which is not shared between lcores in
> the normal case and the access of this variable should be ordered on the
> same core. However, if non-EAL thread pick the highest lcore to insert timers
> into, there is the possibility of conflicts on this flag between threads. Then
> the atomic CAS operation is needed.
> 
> Use the c11 atomic CAS instead of the generic rte_atomic operations to avoid
> the unnecessary barrier on aarch64.
> 
> Signed-off-by: Phil Yang <phil.yang at arm.com>
> Reviewed-by: Dharmik Thakkar <dharmik.thakkar at arm.com>
> Reviewed-by: Ruifeng Wang <ruifeng.wang at arm.com>
Acked-by: Erik Gabriel Carrillo <erik.g.carrillo at intel.com>