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Date:   Sun, 13 Nov 2022 09:37:59 +0200
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Subject: Re: [PATCH 0/4] cpumask: improve on cpumask_local_spread() locality
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To:     Yury Norov <yury.norov@gmail.com>, Jakub Kicinski <kuba@kernel.org>
Cc:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        "David S. Miller" <davem@davemloft.net>,
        Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Barry Song <baohua@kernel.org>,
        Ben Segall <bsegall@google.com>,
        Daniel Bristot de Oliveira <bristot@redhat.com>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Gal Pressman <gal@nvidia.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Heiko Carstens <hca@linux.ibm.com>,
        Ingo Molnar <mingo@redhat.com>,
        Jason Gunthorpe <jgg@nvidia.com>,
        Jesse Brandeburg <jesse.brandeburg@intel.com>,
        Jonathan Cameron <Jonathan.Cameron@huawei.com>,
        Juri Lelli <juri.lelli@redhat.com>,
        Leon Romanovsky <leonro@nvidia.com>,
        Mel Gorman <mgorman@suse.de>,
        Peter Zijlstra <peterz@infradead.org>,
        Rasmus Villemoes <linux@rasmusvillemoes.dk>,
        Saeed Mahameed <saeedm@nvidia.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Tariq Toukan <tariqt@nvidia.com>,
        Tony Luck <tony.luck@intel.com>,
        Valentin Schneider <vschneid@redhat.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        linux-crypto@vger.kernel.org, Netdev <netdev@vger.kernel.org>,
        "open list:HFI1 DRIVER" <linux-rdma@vger.kernel.org>
References: <20221111040027.621646-1-yury.norov@gmail.com>
 <20221111082551.7e71fbf4@kernel.org>
 <CAAH8bW9jG5US0Ymn1wax9tNK3MgZpcWfQsYgu-Km_E+WZw3yiA@mail.gmail.com>
From:   Tariq Toukan <ttoukan.linux@gmail.com>
In-Reply-To: <CAAH8bW9jG5US0Ymn1wax9tNK3MgZpcWfQsYgu-Km_E+WZw3yiA@mail.gmail.com>
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On 11/11/2022 6:47 PM, Yury Norov wrote:
> 
> 
> On Fri, Nov 11, 2022, 10:25 AM Jakub Kicinski <kuba@kernel.org 
> <mailto:kuba@kernel.org>> wrote:
> 
>     On Thu, 10 Nov 2022 20:00:23 -0800 Yury Norov wrote:
>      > cpumask_local_spread() currently checks local node for presence
>     of i'th
>      > CPU, and then if it finds nothing makes a flat search among all
>     non-local
>      > CPUs. We can do it better by checking CPUs per NUMA hops.
> 
>     Nice.
> 

Thanks for your series.
This improves them all, with no changes required to the network device 
drivers.

>      > This series is inspired by Valentin Schneider's "net/mlx5e:
>     Improve remote
>      > NUMA preferences used for the IRQ affinity hints"
>      >
>      >
>     https://patchwork.kernel.org/project/netdevbpf/patch/20220728191203.4055-3-tariqt@nvidia.com/ <https://patchwork.kernel.org/project/netdevbpf/patch/20220728191203.4055-3-tariqt@nvidia.com/>


Find my very first version here, including the perf testing results:
https://patchwork.kernel.org/project/netdevbpf/list/?series=660413&state=*


>      >
>      > According to Valentin's measurements, for mlx5e:
>      >
>      >       Bottleneck in RX side is released, reached linerate (~1.8x
>     speedup).
>      >       ~30% less cpu util on TX.
>      >
>      > This patch makes cpumask_local_spread() traversing CPUs based on NUMA
>      > distance, just as well, and I expect comparabale improvement for its
>      > users, as in Valentin's case.
>      >

Right.

>      > I tested it on my VM with the following NUMA configuration:
> 
>     nit: the authorship is a bit more complicated, it'd be good to mention
>     Tariq. Both for the code and attribution of the testing / measurements.
> 
> 
> Sure. Tariq and Valentine please send your tags as appropriate.
> 

I wonder what fits best here?

As the contribution is based upon previous work that I developed, then 
probably:
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>

Thanks,
Tariq