From: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
To: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Cc: GNU C Library <libc-alpha@sourceware.org>
Subject: Re: [PATCH] Remove catomics
Date: Tue, 5 Jul 2022 11:16:49 +0000 [thread overview]
Message-ID: <AM5PR0801MB16687EADE28456267CBF458983819@AM5PR0801MB1668.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <A8970DF4-4066-40E0-96D7-D3AF40227B12@linaro.org>
Hi Adhemerval,
> Since this patch removes a x86 optimization (sorry, I realized it after my review),
> I think it would be better if circle back and first get my single-thread refactor
> patches in (which fixes SINGLE_THREAD_P syscall on aarch64 and other architectures)
> since it does not change x86.
It's a typical target "optimization" - not only slower but also functionally incorrect...
> After we can then remove the unused catomic operation and make the single-thread
> optimization locking generic (so we can finally remove x86 arch-specific bits).
I'm not sure I'm following - the catomics are not used in any locks or in performance
critical code that could benefit from single-threaded optimizations. In fact my patch
improves performance by using much faster relaxed atomics (since all we need is
atomicity for the counter increments).
Single-threaded locking optimizations are completely independent of all this, and so is
your SINGLE_THREAD_P patch.
So the only concern here is rebase clashes due to your patch rewriting all the x86 code.
My point is that this unnecessary. The catomics are useless and all of the target specific
code can be removed since it is either unused already or will be soon after follow-up
patches. So why first rewrite it all? It just seems lots of work for no gain...
Cheers,
Wilco
next prev parent reply other threads:[~2022-07-05 11:17 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-16 10:01 Wilco Dijkstra
2022-06-16 20:06 ` Adhemerval Zanella
2022-06-17 11:56 ` Wilco Dijkstra
2022-06-22 13:00 ` Adhemerval Zanella
2022-07-05 11:16 ` Wilco Dijkstra [this message]
2022-07-06 12:15 ` Adhemerval Zanella
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