24/04/2020 09:24, Phil Yang:
> Volatile has no ordering semantics. The rte_timer structure defines
> timer status as a volatile variable and uses the rte_r/wmb barrier
> to guarantee inter-thread visibility.
>
> This patch optimized the volatile operation with c11 atomic operations
> and one-way barrier to save the performance penalty. According to the
> timer_perf_autotest benchmarking results, this patch can uplift 10%~16%
> timer appending performance, 3%~20% timer resetting performance and 45%
> timer callbacks scheduling performance on aarch64 and no loss in
> performance for x86.
>
> Suggested-by: Honnappa Nagarahalli <honnappa.nagaraha...@arm.com>
> Signed-off-by: Phil Yang <phil.y...@arm.com>
> Reviewed-by: Gavin Hu <gavin...@arm.com>
> Acked-by: Erik Gabriel Carrillo <erik.g.carri...@intel.com>
[...]
> --- a/lib/librte_timer/rte_timer.h
> +++ b/lib/librte_timer/rte_timer.h
> @@ -101,7 +101,7 @@ struct rte_timer
> - volatile union rte_timer_status status; /**< Status of timer. */
> + union rte_timer_status status; /**< Status of timer. */
Unfortunately, I cannot merge this patch because it breaks the ABI:
[C]'function void rte_timer_init(rte_timer*)' at rte_timer.c:214:1 has some
indirect sub-type changes:
parameter 1 of type 'rte_timer*' has sub-type changes:
in pointed to type 'struct rte_timer' at rte_timer.h:100:1:
type size hasn't changed
1 data member changes (2 filtered):
type of 'volatile rte_timer_status rte_timer::status' changed:
entity changed from 'volatile rte_timer_status' to 'union
rte_timer_status' at rte_timer.h:67:1
type size hasn't changed
