Re: [PATCH] docs: iostats: Rewrite intro, remove outdated formats

[Bagas Sanjaya <bagasdotme@gmail.com>]

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On Thu, Feb 13, 2025 at 09:14:30PM -0800, David Reaver wrote:
> The discussion of file formats for very old kernel versions obscured the
> key information in this document. Additionally, the introduction was
> missing a discussion of flush fields added in b6866318657 ("block: add
> iostat counters for flush requests") [1].
> 
> Rewrite the introduction to discuss only the current kernel's disk I/O stat
> file formats. Also, clean up wording to be more concise.
> 
> Link: https://lore.kernel.org/lkml/157433282607.7928.5202409984272248322.stgit@buzz/T/ [1]
> 
> Signed-off-by: David Reaver <me@davidreaver.com>
> ---
> 
> Thanks for the encouragement Randy. Here is a rewrite of the intro.
> 
> This patch is mutually exclusive with the original patch I started this
> thread with. Let me know if I should submit it as a standalone thread.
> (I'm fairly new to contributing to the kernel.)

This is [PATCH v2] so the next version should be [PATCH v3] (sent as
separate thread).

> +All fields are cumulative, monotonic counters that start at zero at
> +boot, except for field 9, which resets to zero as I/Os complete. Other
> +fields only increase unless they overflow and wrap. Wrapping may occur
> +on long-running or high-load systems, so applications should handle this
> +properly. Field types are either 32-bit unsigned integers or unsigned
> +longs, which may be 32-bit or 64-bit depending on the architecture. As
> +long as observations are taken at reasonable intervals, wraparounds
> +should be rare.

So on x86_64 the field type is 32-bit-sized (u32) instead of u64, right?

Confused...

-- 
An old man doll... just what I always wanted! - Clara

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