Message-ID: <ZpRjDDKGq1F4cSBr@archie.me>
Date: Mon, 15 Jul 2024 06:45:16 +0700
From: Bagas Sanjaya <bagasdotme@...il.com>
To: Shi-Wu, Lo（Gmail） <shiwulo@...il.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Cc: Ingo Molnar <mingo@...hat.com>, Will Deacon <will@...nel.org>,
	Waiman Long <longman@...hat.com>, Boqun Feng <boqun.feng@...il.com>,
	Peter Zijlstra <peterz@...radead.org>, Mel Gorman <mgorman@...e.de>,
	Thomas Gleixner <tglx@...utronix.de>,
	Borislav Petkov <bp@...en8.de>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	"H. Peter Anvin" <hpa@...or.com>, Theodore Ts'o <tytso@....edu>
Subject: Re: A new spinlock for multicore (>16) platform

On Mon, Jul 15, 2024 at 01:07:40AM +0800, Shi-Wu, Lo（Gmail） wrote:
> Dear Linux Contributors,
> I am a Linux enthusiast from Taiwan, and I hope to contribute to the
> Linux kernel. We have developed a new spinlock method that has been
> validated on AMD 64-core and AMD 32-core processors. Compared to
> previous methods, this new method is optimized in the following areas:
> 
> Motivation and Approaches:
> 1. As the number of cores increases, there is a need for more refined
> optimization of the data transmission paths between cores.
> 2. Data transmission usually involves lock-unlock wrapping.
> 3. Performance improvement can be achieved using a shortest path
> approximation algorithm.
>    A detailed introduction to this method can be found in the following paper:
> https://www.usenix.org/conference/osdi23/presentation/lo
> 
> Our laboratory is currently developing a system that can apply the
> same optimization strategy to all multi-core processors. Below is our
> plan.
> 
> The New Method and Its Compatibility with qspinlock:
> 1. The default algorithm in the Linux kernel remains qspinlock.
> 2. A new file is created in /proc/routing_path, where a shortest path
> can be input, for example:
> sudo echo 1,2,3,4,16,17,18,19,5,6,7,8,11,12,13,14 > /proc/routing_path
> 3. After inputting the shortest path, the kernel switches to using the
> RON algorithm.
> 
> Expected Outcomes:
> According to our measurements on AMD 32-core and AMD 64-core
> processors, Google LevelDB can achieve a 3-4% speed improvement.
> 
> Comparison with Previous NUMA-aware algorithms:
> Compared to NUMA-aware results, since such systems may contain more
> than two processors, the communication cost between processors is much
> higher than the communication cost between cores (within the same
> processor). Our method focuses on multiple cores within a single
> processor, making it multicore-aware. If a NUMA-aware algorithm is
> used in a multicore environment, it is not as effective as a
> multicore-aware algorithm. (Please refer to the paper,
> https://www.usenix.org/conference/osdi23/presentation/lo)
> 
> Assistance Needed:
> I would like to understand if the Linux kernel community is interested
> in this new spinlock method. As a teacher, I cannot complete all the
> work by myself. Is anyone willing to collaborate with me on this
> project?
> 
> Sorry to bother you:
> I apologize for taking up so much of your time with this letter.
> Although I am quite old, this is the first time I feel that my
> research results are good enough to contribute to the Linux community.
> I have read the relevant documentation, and it made me realize that my
> time and abilities are insufficient to write the high-quality code
> required by the Linux community. Therefore, I ask for your guidance.

I can't really say about this topic (as I'm not subject-matter expert here),
so Cc: relevant maintainers.

Thanks!

-- 
An old man doll... just what I always wanted! - Clara

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