From: Dave Martin <Dave.Martin@arm.com>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Julien Grall <julien.grall@arm.com>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
linux-rt-users@vger.kernel.org,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [RFC PATCH] arm64/fpsimd: Don't disable softirq when touching FPSIMD/SVE state
Date: Thu, 14 Feb 2019 10:34:52 +0000 [thread overview]
Message-ID: <20190214103449.GN3567@e103592.cambridge.arm.com> (raw)
In-Reply-To: <20190213165227.7ekekkxazhbaqxoe@linutronix.de>
On Wed, Feb 13, 2019 at 05:52:27PM +0100, Sebastian Andrzej Siewior wrote:
> On 2019-02-13 16:40:00 [+0100], Ard Biesheuvel wrote:
> > > > This is equal what x86 is currently doing. The naming is slightly
> > > > different, there is irq_fpu_usable().
> > >
> > > Yes, I think it's basically the same idea.
> > >
> > > It's been evolving a bit on both sides, but is quite similar now.
> > >
> >
> > may_use_simd() only exists because we have a generic crypto SIMD
> > helper, and so we needed something arch agnostic to wrap around
> > irq_fpu_usable()
>
> My question was more if this is helpful and we want to keep or if
> it would be better to remove it and always disable BH as part of SIMD
> operations.
Wouldn't this arbitrarily increase softirq latency? Unconditionally
forbidding SIMD in softirq might make more sense. It depends on how
important the use cases are...
Cheers
---Dave
next prev parent reply other threads:[~2019-02-14 10:34 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-08 16:55 [RFC PATCH] arm64/fpsimd: Don't disable softirq when touching FPSIMD/SVE state Julien Grall
2019-02-12 17:13 ` Julia Cartwright
2019-02-18 14:07 ` Julien Grall
2019-02-13 14:30 ` Sebastian Andrzej Siewior
2019-02-13 15:36 ` Dave Martin
2019-02-13 15:40 ` Ard Biesheuvel
2019-02-13 15:42 ` Dave Martin
2019-02-13 16:52 ` Sebastian Andrzej Siewior
2019-02-14 10:34 ` Dave Martin [this message]
2019-02-18 15:07 ` Julien Grall
2019-03-04 17:25 ` Sebastian Andrzej Siewior
2019-03-14 18:07 ` Julien Grall
2019-03-15 10:06 ` Dave Martin
2019-03-15 10:22 ` Julien Grall
2019-02-13 16:50 ` Sebastian Andrzej Siewior
2019-02-18 14:33 ` Julien Grall
2019-02-18 16:32 ` Julien Grall
2019-04-04 10:52 ` Dave Martin
2019-04-05 9:02 ` Julien Grall
2019-04-05 14:39 ` Sebastian Andrzej Siewior
2019-04-05 15:17 ` Julien Grall
2019-04-05 15:42 ` Sebastian Andrzej Siewior
2019-04-11 15:12 ` Julien Grall
2019-04-05 15:07 ` Dave Martin
2019-04-11 15:58 ` Julien Grall
2019-04-11 16:34 ` Dave Martin
2019-04-11 16:50 ` Julien Grall
2019-04-11 14:10 ` Julien Grall
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