From: Holger Dengler <dengler@linux.ibm.com>
To: "Jason A. Donenfeld" <Jason@zx2c4.com>
Cc: Harald Freudenberger <freude@linux.ibm.com>,
Heiko Carstens <hca@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Alexander Gordeev <agordeev@linux.ibm.com>,
Christian Borntraeger <borntraeger@linux.ibm.com>,
Juergen Christ <jchrist@linux.ibm.com>,
linux-crypto@vger.kernel.org, linux-s390@vger.kernel.org
Subject: Re: [PATCH v1 1/1] s390/arch_random: Buffer true random data
Date: Tue, 5 Jul 2022 21:28:29 +0200 [thread overview]
Message-ID: <94129ae6-0055-4cc9-dee3-0558cf52b4cb@linux.ibm.com> (raw)
In-Reply-To: <YsSAn2qXqlFkS5sH@zx2c4.com>
Hi Jason,
On 05/07/2022 20:19, Jason A. Donenfeld wrote:
> Hey Holger,
>
> On Tue, Jul 05, 2022 at 07:47:37PM +0200, Holger Dengler wrote:
>> A trng call runs for minimal ~20-190us for 32 bytes. 20us on newer
>> machine generations, 190us on older ones. These are not 100% exact
>> measurements, but the dimension should be correct.
>
> Holy smokes. Yea, okay, I see what you're saying. So indeed it sounds
> like the `!in_hardirq()` addition would be a good idea. Let's do that.
:) I'll come up with this in v2.
For the long run, a re-worked API arch_get_random_seed_something() with an arch-dependant variable block length is worth to think about. It seems, that x86 and ppc delivers a long per trng instruction call, while on s390 it would make more sense to fill the block.rdseed in a single call.
--
Mit freundlichen Grüßen / Kind regards
Holger Dengler
--
IBM Systems, Linux on IBM Z Development
dengler@linux.ibm.com
next prev parent reply other threads:[~2022-07-05 19:28 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-05 11:27 [PATCH v1 0/1] s390/archrandom: use buffered random data Holger Dengler
2022-07-05 11:27 ` [PATCH v1 1/1] s390/arch_random: Buffer true " Holger Dengler
2022-07-05 13:18 ` Jason A. Donenfeld
2022-07-05 13:42 ` Jason A. Donenfeld
2022-07-05 14:58 ` Holger Dengler
2022-07-05 15:11 ` Jason A. Donenfeld
2022-07-05 16:27 ` Holger Dengler
2022-07-05 16:35 ` Jason A. Donenfeld
2022-07-05 17:47 ` Holger Dengler
2022-07-05 18:19 ` Jason A. Donenfeld
2022-07-05 19:28 ` Holger Dengler [this message]
2022-07-06 16:18 ` Harald Freudenberger
2022-07-06 16:26 ` Jason A. Donenfeld
2022-07-06 18:29 ` Christian Borntraeger
2022-07-06 22:34 ` Jason A. Donenfeld
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=94129ae6-0055-4cc9-dee3-0558cf52b4cb@linux.ibm.com \
--to=dengler@linux.ibm.com \
--cc=Jason@zx2c4.com \
--cc=agordeev@linux.ibm.com \
--cc=borntraeger@linux.ibm.com \
--cc=freude@linux.ibm.com \
--cc=gor@linux.ibm.com \
--cc=hca@linux.ibm.com \
--cc=jchrist@linux.ibm.com \
--cc=linux-crypto@vger.kernel.org \
--cc=linux-s390@vger.kernel.org \
/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