From: Christopher Lameter <cl@linux.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Wei Yang <richard.weiyang@gmail.com>,
penberg@kernel.org, mhocko@kernel.org, linux-mm@kvack.org,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
David Rientjes <rientjes@google.com>
Subject: Re: [PATCH v2] mm/slub: improve performance by skipping checked node in get_any_partial()
Date: Fri, 21 Dec 2018 01:37:38 +0000 [thread overview]
Message-ID: <01000167ce692d0d-ef68fdc8-4c30-40a4-8ca5-afbc3773c075-000000@email.amazonses.com> (raw)
In-Reply-To: <20181220144107.9376344c2be687615ea9aa69@linux-foundation.org>
On Thu, 20 Dec 2018, Andrew Morton wrote:
> The result of (get_partial_count / get_partial_try_count):
>
> +----------+----------------+------------+-------------+
> | | Base | Patched | Improvement|
> +----------+----------------+------------+-------------+
> |One Node | 1:3 | 1:0 | - 100% |
If you have one node then you already searched all your slabs. So we could
completely skip the get_any_partial() functionality in the non NUMA case
(if nr_node_ids == 1)
> +----------+----------------+------------+-------------+
> |Four Nodes| 1:5.8 | 1:2.5 | - 56% |
> +----------+----------------+------------+-------------+
Hmm.... Ok but that is the extreme slowpath.
> Each version/system configuration combination has four round kernel
> build tests. Take the average result of real to compare.
>
> +----------+----------------+------------+-------------+
> | | Base | Patched | Improvement|
> +----------+----------------+------------+-------------+
> |One Node | 4m41s | 4m32s | - 4.47% |
> +----------+----------------+------------+-------------+
> |Four Nodes| 4m45s | 4m39s | - 2.92% |
> +----------+----------------+------------+-------------+
3% on the four node case? That means that the slowpath is taken
frequently. Wonder why?
Can we also see the variability? Since this is a NUMA system there is
bound to be some indeterminism in those numbers.
next prev parent reply other threads:[~2018-12-21 1:37 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-11-08 1:12 [PATCH] mm/slub: skip node in case there is no slab to acquire Wei Yang
2018-11-09 20:48 ` Andrew Morton
2018-11-09 23:47 ` Wei Yang
2018-11-13 9:12 ` [PATCH v2] " Wei Yang
2018-11-13 13:17 ` [PATCH] " Michal Hocko
2018-11-13 13:26 ` Wei Yang
2018-11-13 13:34 ` Michal Hocko
2018-11-20 3:31 ` [PATCH v2] mm/slub: improve performance by skipping checked node in get_any_partial() Wei Yang
2018-11-22 3:05 ` Andrew Morton
2018-11-22 9:13 ` Wei Yang
2018-11-22 23:41 ` Wei Yang
2018-11-23 13:39 ` Michal Hocko
2018-11-23 13:49 ` Michal Hocko
2018-11-23 15:27 ` Wei Yang
2018-12-20 22:41 ` Andrew Morton
2018-12-21 0:25 ` Alexander Duyck
2018-12-21 3:29 ` Wei Yang
2018-12-21 1:37 ` Christopher Lameter [this message]
2018-12-21 1:37 ` Christopher Lameter
2018-12-21 3:33 ` Wei Yang
2018-12-24 22:03 ` Wei Yang
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