Re: [RFC v1 0/2] slabinfo: sheaves statistics support

[Harry Yoo <harry.yoo@oracle.com>]

On Mon, Apr 07, 2025 at 01:18:08PM +0900, Harry Yoo wrote:
> With this series, `slabinfo -r` now prints sheaves statistics (if enabled).
> Written on top of slub-percpu-sheaves-v4r0 [1] branch.
> 
> Q1: Vlastimil, do you want to integrate this into the sheaves series or do
> you want me to send it as a follow-up series after sheaves land mainline?
> 
> Q2: 'sheaf_swap' does not fit into the table because SLUB swaps sheaves both
> at alloc and free. Probably split the counter?

Q3: Having 'Add sheaves to the barn' & 'Remove sheaves from the barn' counters
might help better understand the behavior? (just like 'Add partial' /
'Remove partial' pair in the normal SLUB path).

-- 
Cheers,
Harry (formerly known as Hyeonggon)

> [1] https://git.kernel.org/pub/scm/linux/kernel/git/vbabka/linux.git/log/?h=slub-percpu-sheaves-v4r0
> 
> $ sudo ./slabinfo -r maple_node
> Slabcache: maple_node       Aliases:  0 Order :  1 Objects: 8268
> 
> [... snip ...]
> 
> Slab Perf Counter       Alloc     Free %Al %Fr
> ----------------------------------------------
> Fastpath               258760     5109  93   3
> Slowpath                18205   126605   6  96
> Page Alloc                903      520   0   0
> Add partial                 0    14600   0  11
> Remove partial           3472      420   1   0
> Cpu partial list        12235    16577   4  12
> RemoteObj/SlabFrozen        0     5969   0   4
> Total                  276965   131714
> 
> 
> Slab Sheaves Counter       Alloc    Free  %Al  %Fr  %Fa
> -------------------------------------------------------
> Served from sheaves     1805673   580161   86   93  N/A
> Sheaves refill           236384      N/A   13  N/A  N/A
> Sheaves alloc              3872     3794    0    0  N/A
> Free to RCU sheaves         N/A  1255815  N/A   68    0
> Main sheaf flush            N/A        0  N/A    0  N/A
> Other sheaves flush         N/A   265600  N/A   14  N/A
> 
> Slab Deactivation             Occurrences %
> -------------------------------------------
> Slab full                           0    0%
> Slab empty                        100    0%
> Moved to head of partial list       0    0%
> Moved to tail of partial list       0    0%
> Deactivation bypass             16588   99%
> Refilled from foreign frees      1595    9%
> Node mismatch                       0    0%
> 
> Harry Yoo (2):
>   mm/slab: add sheaves_enabled read-only sysfs file
>   tools/mm/slabinfo: add support for sheaves stats
> 
>  mm/slub.c           | 10 ++++++++
>  tools/mm/slabinfo.c | 62 +++++++++++++++++++++++++++++++++++++++++++--
>  2 files changed, 70 insertions(+), 2 deletions(-)
> 
> -- 
> 2.43.0
>