[dm-devel] [PATCH v2 17/20] libmultipath: path latency: fix default base num

[Guan Junxiong]

Looks Good.

Reviewed-by Guan Junxiong <guanjunxiong at huawei.com>

On 2018/1/14 5:19, Martin Wilck wrote:
> I don't think anyone can measure latency to 1% accuracy. It's
> better to not even pretend to be able to. 10% should be fine
> even for the most latency-critical environments.
> ---
>  libmultipath/prioritizers/path_latency.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/libmultipath/prioritizers/path_latency.c b/libmultipath/prioritizers/path_latency.c
> index 9d5397ec1b3a..b8c5bc7c50a4 100644
> --- a/libmultipath/prioritizers/path_latency.c
> +++ b/libmultipath/prioritizers/path_latency.c
> @@ -42,8 +42,9 @@
>  #define DEF_IO_NUM		100
>  
>  #define MAX_BASE_NUM		10
> -#define MIN_BASE_NUM		1.01
> -#define DEF_BASE_NUM		1.5
> +#define MIN_BASE_NUM		1.1
> +// This is 10**(1/4). 4 prio steps correspond to a factor of 10.
> +#define DEF_BASE_NUM		1.77827941004
>  
>  #define MAX_AVG_LATENCY		100000000.	/* Unit: us */
>  #define MIN_AVG_LATENCY		1.		/* Unit: us */
>