[dpdk-dev] [EXT] [PATCH v1] ticketlock: ticket based to improve fairness

[Jerin Jacob Kollanukkaran]

On Sun, 2019-01-13 at 22:46 +0800, Gavin Hu wrote:
> -------------------------------------------------------------------
> ---
> From: Joyce Kong <joyce.kong at arm.com>
> 
> The spinlock implementation is unfair, some threads may take locks
> aggressively while leaving the other threads starving for long time.
> As
> shown in the following test, within same period of time, there are
> threads taking locks much more times than the others.
> 
> The ticketlock gives each waiting thread a ticket and they can take
> the
> lock one by one, first come, first serviced, this avoids starvation
> for
> too long time and is more predictable.
> 
> *** spinlock_autotest without this patch ***
> Core [0] count = 89
> Core [1] count = 84
> Core [2] count = 94
> ...
> Core [208] count = 171
> Core [209] count = 152
> Core [210] count = 161
> Core [211] count = 187
> 
> *** spinlock_autotest with this patch ***

This comment needs to be updated as it is new API now
and we need add test case for the same. I think,
making modification to exiting spinlock test case would be fine.


> Core [0] count = 534
> Core [1] count = 533
> Core [2] count = 542
> ...
> Core [208] count = 554
> Core [209] count = 556
> Core [210] count = 555
> Core [211] count = 551
> 
> Signed-off-by: Joyce Kong <joyce.kong at arm.com>
> Signed-off-by: Gavin Hu <gavin.hu at arm.com>
> ---
>