Re: [PATCH 1/2] btrfs: set default discard iops_limit to 1000

[Roman Mamedov <rm@romanrm.net>]

On Wed,  5 Apr 2023 09:20:32 -0700
Boris Burkov <boris@bur.io> wrote:

> Previously, the default was a relatively conservative 10. This results
> in a 100ms delay, so with ~300 discards in a commit, it takes the full
> 30s till the next commit to finish the discards. On a workstation, this
> results in the disk never going idle, wasting power/battery, etc.
> 
> Set the default to 1000, which results in using the smallest possible
> delay, currently, which is 1ms. This has shown to not pathologically
> keep the disk busy by the original reporter.
> 
> Link: https://lore.kernel.org/linux-btrfs/ZCxKc5ZzP3Np71IC@infradead.org/T/#m6ebdeb475809ed7714b21b8143103fb7e5a966da
> Signed-off-by: Boris Burkov <boris@bur.io>
> ---
>  fs/btrfs/discard.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/btrfs/discard.c b/fs/btrfs/discard.c
> index 317aeff6c1da..aef789bcff8f 100644
> --- a/fs/btrfs/discard.c
> +++ b/fs/btrfs/discard.c
> @@ -60,7 +60,7 @@
>  #define BTRFS_DISCARD_TARGET_MSEC	(6 * 60 * 60UL * MSEC_PER_SEC)
>  #define BTRFS_DISCARD_MIN_DELAY_MSEC	(1UL)
>  #define BTRFS_DISCARD_MAX_DELAY_MSEC	(1000UL)
> -#define BTRFS_DISCARD_MAX_IOPS		(10U)
> +#define BTRFS_DISCARD_MAX_IOPS		(10000U)

But the patch sets 10000?

>  
>  /* Monotonically decreasing minimum length filters after index 0 */
>  static int discard_minlen[BTRFS_NR_DISCARD_LISTS] = {


-- 
With respect,
Roman