Re: [PATCH v3 01/18] Documentation, ABI: Add a document entry for cache id
From: Nilay Vaish
Date: Sat Oct 08 2016 - 13:12:57 EST
On 7 October 2016 at 21:45, Fenghua Yu <fenghua.yu@xxxxxxxxx> wrote:
> From: Fenghua Yu <fenghua.yu@xxxxxxxxx>
> Add an ABI document entry for /sys/devices/system/cpu/cpu*/cache/index*/id.
> Signed-off-by: Fenghua Yu <fenghua.yu@xxxxxxxxx>
> Signed-off-by: Tony Luck <tony.luck@xxxxxxxxx>
> Documentation/ABI/testing/sysfs-devices-system-cpu | 16 ++++++++++++++++
> 1 file changed, 16 insertions(+)
> diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu
> index 4987417..b1c3d69 100644
> --- a/Documentation/ABI/testing/sysfs-devices-system-cpu
> +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu
> @@ -272,6 +272,22 @@ Description: Parameters for the CPU cache attributes
> the modified cache line is written to main
> memory only when it is replaced
> +What: /sys/devices/system/cpu/cpu*/cache/index*/id
> +Date: September 2016
> +Contact: Linux kernel mailing list <linux-kernel@xxxxxxxxxxxxxxx>
> +Description: Cache id
> + The id provides a unique name for a specific instance of
> + a cache of a particular type. E.g. there may be a level
> + 3 unified cache on each socket in a server and we may
> + assign them ids 0, 1, 2, ...
> + Note that id value may not be contiguous. E.g. level 1
> + caches typically exist per core, but there may not be a
> + power of two cores on a socket, so these caches may be
> + numbered 0, 1, 2, 3, 4, 5, 8, 9, 10, ...
While it is ok that the caches are not numbered contiguously, it is
unclear how this is related to number of cores on a socket being a
power of 2 or not.