From: Dave Martin <Dave.Martin@arm.com>
To: Julien Grall <julien.grall@arm.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Ard Biesheuvel <ard.biesheuvel@linaro.org>,
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: Fri, 15 Mar 2019 10:06:37 +0000 [thread overview]
Message-ID: <20190315100634.GN3567@e103592.cambridge.arm.com> (raw)
In-Reply-To: <abd861af-023f-2f9e-acee-4e1837aa8897@arm.com>
On Thu, Mar 14, 2019 at 06:07:19PM +0000, Julien Grall wrote:
> Hi Sebastian,
>
> On 3/4/19 5:25 PM, Sebastian Andrzej Siewior wrote:
[...]
> >It would increase the softirq latency but the question is how bad would
> >it be. It would continue once the SIMD section is done.
>
> On Arm, the kernel may use either FPSIMD or SVE (if supported by the
> platform). While the FPSIMD context is fairly small (~4K), the SVE context
> can be up to ~64KB.
It's not quite as bad as that. The FPSIMD state is ~0.5K, with the SVE
state size being up to ~8.5K (though for today's implementations ~2K may
be considered typical).
For comparision, I believe AVX-512 has ~2K of state.
Cheers
---Dave
next prev parent reply other threads:[~2019-03-15 10:06 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-08 16:55 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
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 [this message]
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
2019-02-08 17:03 [PATCH 0/3] Remove reference of TIF_USEDFPU on arch not using it Julien Grall
2019-02-08 17:03 ` [RFC PATCH] arm64/fpsimd: Don't disable softirq when touching FPSIMD/SVE state Julien Grall
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190315100634.GN3567@e103592.cambridge.arm.com \
--to=dave.martin@arm.com \
--cc=ard.biesheuvel@linaro.org \
--cc=bigeasy@linutronix.de \
--cc=catalin.marinas@arm.com \
--cc=julien.grall@arm.com \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-rt-users@vger.kernel.org \
--cc=will.deacon@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
all inboxes | Powered by JetHome®