From: "Guo, Wangyang" <wangyang.guo@intel.com>
To: Ming Lei <ming.lei@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Keith Busch <kbusch@kernel.org>, Jens Axboe <axboe@fb.com>,
Christoph Hellwig <hch@lst.de>, Sagi Grimberg <sagi@grimberg.me>,
linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org,
virtualization@lists.linux-foundation.org,
linux-block@vger.kernel.org, Tianyou Li <tianyou.li@intel.com>,
Tim Chen <tim.c.chen@linux.intel.com>,
Dan Liang <dan.liang@intel.com>
Subject: Re: [PATCH RESEND] lib/group_cpus: make group CPU cluster aware
Date: Tue, 18 Nov 2025 14:29:20 +0800 [thread overview]
Message-ID: <da1d6b4e-038c-48dc-830d-5eadb3ac943f@intel.com> (raw)
In-Reply-To: <aRU2sC5q5hCmS_eM@fedora>
On 11/13/2025 9:38 AM, Ming Lei wrote:
> On Wed, Nov 12, 2025 at 11:02:47AM +0800, Guo, Wangyang wrote:
>> On 11/11/2025 8:08 PM, Ming Lei wrote:
>>> On Tue, Nov 11, 2025 at 01:31:04PM +0800, Guo, Wangyang wrote:
>>> They still should share same L3 cache, and cpus_share_cache() should be
>>> true when the IO completes on the CPU which belong to different L2 with the
>>> submission CPU, and remote completion via IPI won't be triggered.
>> Yes, remote IPI not triggered.
>
> OK, in my test on AMD zen4, NVMe performance can be dropped to 1/2 - 1/3 if
> remote IPI is triggered in case of crossing L3, which is understandable.
>
> I will check if topo cluster can cover L3, if yes, the patch still can be
> simplified a lot by introducing sub-node spread by changing build_node_to_cpumask()
> and adding nr_sub_nodes.
Do you mean using cluster as "NUMA" nodes to spread CPU, instead of two
level NUMA-cluster spreading?
BR
Wangyang
next prev parent reply other threads:[~2025-11-18 6:29 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-11 2:06 [PATCH RESEND] lib/group_cpus: make group CPU cluster aware Wangyang Guo
2025-11-11 3:25 ` Ming Lei
2025-11-11 5:31 ` Guo, Wangyang
2025-11-11 12:08 ` Ming Lei
2025-11-12 3:02 ` Guo, Wangyang
2025-11-13 1:38 ` Ming Lei
2025-11-13 3:32 ` Guo, Wangyang
2025-11-18 6:29 ` Guo, Wangyang [this message]
2025-11-19 1:52 ` Ming Lei
2025-11-24 7:58 ` Guo, Wangyang
2025-12-08 2:47 ` Guo, Wangyang
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