From: Breno Leitao <leitao@debian.org>
To: Chuck Lever <chuck.lever@oracle.com>
Cc: Tejun Heo <tj@kernel.org>, Lai Jiangshan <jiangshanlai@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel@vger.kernel.org, puranjay@kernel.org,
linux-crypto@vger.kernel.org, linux-btrfs@vger.kernel.org,
linux-fsdevel@vger.kernel.org,
Michael van der Westhuizen <rmikey@meta.com>,
kernel-team@meta.com
Subject: Re: [PATCH RFC 0/5] workqueue: add WQ_AFFN_CACHE_SHARD affinity scope
Date: Wed, 18 Mar 2026 10:51:15 -0700 [thread overview]
Message-ID: <abrkrZc52h0vcTTj@gmail.com> (raw)
In-Reply-To: <30adaf6c-657c-41f1-9234-79d807d74f02@oracle.com>
On Tue, Mar 17, 2026 at 09:58:54AM -0400, Chuck Lever wrote:
> On 3/17/26 7:32 AM, Breno Leitao wrote:
> >> - How was the default shard size of 8 picked? There's a tradeoff
> >> between the number of kworkers created and locality. Can you also
> >> report the number of kworkers for each configuration? And is there
> >> data on different shard sizes? It'd be useful to see how the numbers
> >> change across e.g. 4, 8, 16, 32.
> >
> > The choice of 8 as the default shard size was somewhat arbitrary – it was
> > selected primarily to generate initial data points.
>
> Perhaps instead of basing the sharding on a particular number of CPUs
> per shard, why not cap the total number of shards? IIUC that is the main
> concern about ballooning the number of kworker threads.
That's a great suggestion. I'll send a v2 that implements this approach,
where the parameter specifies the number of shards rather than the number
of CPUs per shard.
Thanks for the feedback,
--breno
next prev parent reply other threads:[~2026-03-18 17:51 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-12 16:12 [PATCH RFC 0/5] workqueue: add WQ_AFFN_CACHE_SHARD affinity scope Breno Leitao
2026-03-12 16:12 ` [PATCH RFC 1/5] workqueue: fix parse_affn_scope() prefix matching bug Breno Leitao
2026-03-13 17:41 ` Tejun Heo
2026-03-12 16:12 ` [PATCH RFC 2/5] workqueue: add WQ_AFFN_CACHE_SHARD affinity scope Breno Leitao
2026-03-12 16:12 ` [PATCH RFC 3/5] workqueue: set WQ_AFFN_CACHE_SHARD as the default " Breno Leitao
2026-03-12 16:12 ` [PATCH RFC 4/5] workqueue: add test_workqueue benchmark module Breno Leitao
2026-03-12 16:12 ` [PATCH RFC 5/5] tools/workqueue: add CACHE_SHARD support to wq_dump.py Breno Leitao
2026-03-13 17:57 ` [PATCH RFC 0/5] workqueue: add WQ_AFFN_CACHE_SHARD affinity scope Tejun Heo
2026-03-17 11:32 ` Breno Leitao
2026-03-17 13:58 ` Chuck Lever
2026-03-18 17:51 ` Breno Leitao [this message]
2026-03-18 23:00 ` Tejun Heo
2026-03-19 14:02 ` Breno Leitao
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