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From: John Hubbard <jhubbard@nvidia.com>
To: Lyude Paul <lyude@redhat.com>,
	rust-for-linux@vger.kernel.org, linux-kernel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>
Cc: "Boqun Feng" <boqun.feng@gmail.com>,
	"Daniel Almeida" <daniel.almeida@collabora.com>,
	"Miguel Ojeda" <ojeda@kernel.org>,
	"Alex Gaynor" <alex.gaynor@gmail.com>,
	"Gary Guo" <gary@garyguo.net>,
	"Björn Roy Baron" <bjorn3_gh@protonmail.com>,
	"Benno Lossin" <lossin@kernel.org>,
	"Andreas Hindborg" <a.hindborg@kernel.org>,
	"Alice Ryhl" <aliceryhl@google.com>,
	"Trevor Gross" <tmgross@umich.edu>,
	"Danilo Krummrich" <dakr@kernel.org>,
	"Andrew Morton" <akpm@linux-foundation.org>,
	"Peter Zijlstra" <peterz@infradead.org>,
	"Ingo Molnar" <mingo@redhat.com>, "Will Deacon" <will@kernel.org>,
	"Waiman Long" <longman@redhat.com>
Subject: Re: [PATCH v14 00/16] Refcounted interrupts, SpinLockIrq for rust
Date: Thu, 20 Nov 2025 15:16:04 -0800	[thread overview]
Message-ID: <4b6ae41e-5cda-41ab-ba4e-628bdf23f917@nvidia.com> (raw)
In-Reply-To: <20251120214616.14386-1-lyude@redhat.com>

On 11/20/25 1:45 PM, Lyude Paul wrote:
...
>   this new interface is indeed possible, more on this below.
> * Also thank to Joel, we also now have actual benchmarks for how this
>   affects performance:
>   https://lore.kernel.org/rust-for-linux/20250619175335.2905836-1-joelagnelf@nvidia.com/
> * Also some small changes to the kunit test I added, mainly just making
>   sure I don't forget to include a MODULE_DESCRIPTION or MODULE_LICENSE.

Hi,

The above link says that local_interrupt takes 3.6x as as as local_irq.

This is alarming, but is it the final word? In other words, is the Rust
side of this doomed to slower performance forever, or is there some
hope of reaching performance parity with the C part of the kernel?

Do we have to start telling the Rust for Linux story this way: "our
new Rust-based drivers are slower, but memory-safer"?

I'm not able to deduce the answer from a quick scan through the patches
and the cover letter.

thanks,
-- 
John Hubbard


  parent reply	other threads:[~2025-11-20 23:16 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-11-20 21:45 [PATCH v14 00/16] Refcounted interrupts, SpinLockIrq for rust Lyude Paul
2025-11-20 21:45 ` [PATCH v14 01/16] preempt: Introduce HARDIRQ_DISABLE_BITS Lyude Paul
2025-11-20 21:45 ` [PATCH v14 02/16] preempt: Track NMI nesting to separate per-CPU counter Lyude Paul
2025-11-20 21:45 ` [PATCH v14 03/16] preempt: Introduce __preempt_count_{sub, add}_return() Lyude Paul
2025-11-20 21:45 ` [PATCH v14 04/16] irq & spin_lock: Add counted interrupt disabling/enabling Lyude Paul
2025-11-20 21:45 ` [PATCH v14 05/16] irq: Add KUnit test for refcounted interrupt enable/disable Lyude Paul
2025-11-20 21:45 ` [PATCH v14 06/16] rust: Introduce interrupt module Lyude Paul
2025-11-20 21:45 ` [PATCH v14 07/16] rust: helper: Add spin_{un,}lock_irq_{enable,disable}() helpers Lyude Paul
2025-11-20 21:46 ` [PATCH v14 08/16] rust: sync: Add SpinLockIrq Lyude Paul
2025-11-20 21:46 ` [PATCH v14 09/16] rust: sync: Introduce lock::Backend::Context Lyude Paul
2025-11-20 21:46 ` [PATCH v14 10/16] rust: sync: lock: Add `Backend::BackendInContext` Lyude Paul
2025-11-20 21:46 ` [PATCH v14 11/16] rust: sync: lock/global: Rename B to G in trait bounds Lyude Paul
2025-11-20 21:46 ` [PATCH v14 12/16] rust: sync: Add a lifetime parameter to lock::global::GlobalGuard Lyude Paul
2025-11-20 21:46 ` [PATCH v14 13/16] rust: sync: Expose lock::Backend Lyude Paul
2025-11-20 21:46 ` [PATCH v14 14/16] rust: sync: lock/global: Add Backend parameter to GlobalGuard Lyude Paul
2025-11-20 21:46 ` [PATCH v14 15/16] rust: sync: lock/global: Add BackendInContext support to GlobalLock Lyude Paul
2025-11-20 21:46 ` [PATCH v14 16/16] locking: Switch to _irq_{disable,enable}() variants in cleanup guards Lyude Paul
2025-11-20 23:16 ` John Hubbard [this message]
2025-11-21 17:47   ` [PATCH v14 00/16] Refcounted interrupts, SpinLockIrq for rust Boqun Feng
2025-11-22  1:09     ` John Hubbard
2025-11-22  2:38       ` Boqun Feng
2025-11-22  2:56         ` John Hubbard
2025-11-22  3:35           ` Boqun Feng
2025-11-22  4:14             ` John Hubbard
2025-11-22  4:24               ` Boqun Feng

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