Re: [dpdk-dev] [PATCH v3 2/3] test/distributor: replace sync builtins with atomic builtins

[Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>]

> 
> '__sync' built-in functions are deprecated, should use the '__atomic'
> built-in instead. the sync built-in functions are full barriers, while atomic
> built-in functions offer less restrictive one-way barriers, which help
> performance.
> 
> Here is the example test result on TX2:
> sudo ./arm64-armv8a-linuxapp-gcc/app/test -l 112-139 \ -n 4 --socket-
> mem=1024,1024 -- -i
> RTE>>distributor_perf_autotest
> 
> *** distributor_perf_autotest without this patch *** ==== Cache line switch
> test === Time for 33554432 iterations = 1519202730 ticks Ticks per iteration
> = 45
> 
> *** distributor_perf_autotest with this patch *** ==== Cache line switch test
> === Time for 33554432 iterations = 1251715496 ticks Ticks per iteration = 37
> 
> Less ticks needed for the cache line switch test. It got 17% of performance
> improvement.
> 
> Signed-off-by: Phil Yang <phil.yang@arm.com>
> Reviewed-by: Gavin Hu <gavin.hu@arm.com>
> Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
> Reviewed-by: Joyce Kong <joyce.kong@arm.com>
> Reviewed-by: Dharmik Thakkar <dharmik.thakkar@arm.com>
> ---
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>