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From: "rguenther at suse dot de" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/94087] std::random_device often fails when used from multiple threads
Date: Thu, 14 May 2020 11:38:24 +0000	[thread overview]
Message-ID: <bug-94087-4-I5vAnyIQuJ@http.gcc.gnu.org/bugzilla/> (raw)
In-Reply-To: <bug-94087-4@http.gcc.gnu.org/bugzilla/>

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94087

--- Comment #17 from rguenther at suse dot de <rguenther at suse dot de> ---
On Thu, 14 May 2020, redi at gcc dot gnu.org wrote:

> https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94087
> 
> --- Comment #14 from Jonathan Wakely <redi at gcc dot gnu.org> ---
> (In reply to Jonathan Wakely from comment #13)
> > I'd rather not have to do everything shown at
> > https://software.intel.com/content/www/us/en/develop/articles/intel-digital-
> > random-number-generator-drng-software-implementation-guide.html to produce a
> 
> That was meant to link to section 5.2.6 "Generating Seeds from RDRAND"
> https://software.intel.com/content/www/us/en/develop/articles/intel-digital-random-number-generator-drng-software-implementation-guide.html#inpage-nav-5-7
> 
> > stronger seed from RDRAND.
> 
> Given that RDRAND is already an acceptable implementation for
> std::random_device, and the standard makes no guarantees about the
> cryptographic strength of values returned from std::random_device, using RDRAND
> directly is a reasonable alternative.

How about falling back to the mersenne twister?  Or does that invoke
too much overhead in the fallback case?  At least it is reliably
there and cannot fail.

  parent reply	other threads:[~2020-05-14 11:38 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-08  2:51 [Bug libstdc++/94087] New: " coryan+gccbugzilla at google dot com
2020-03-08  7:51 ` [Bug target/94087] " pinskia at gcc dot gnu.org
2020-03-08  7:51 ` pinskia at gcc dot gnu.org
2020-03-08  8:08 ` pinskia at gcc dot gnu.org
2020-03-08 12:04 ` coryan+gccbugzilla at google dot com
2020-03-08 12:09 ` coryan+gccbugzilla at google dot com
2020-03-09  9:44 ` redi at gcc dot gnu.org
2020-03-09 12:10 ` coryan+gccbugzilla at google dot com
2020-03-09 12:24 ` redi at gcc dot gnu.org
2020-04-23  3:30 ` wnereiz at kawashiro dot org
2020-05-14 10:27 ` rguenth at gcc dot gnu.org
2020-05-14 10:30 ` rguenth at gcc dot gnu.org
2020-05-14 10:44 ` redi at gcc dot gnu.org
2020-05-14 10:51 ` redi at gcc dot gnu.org
2020-05-14 11:35 ` redi at gcc dot gnu.org
2020-05-14 11:35 ` hjl.tools at gmail dot com
2020-05-14 11:37 ` rguenther at suse dot de
2020-05-14 11:38 ` rguenther at suse dot de [this message]
2020-05-14 11:41 ` rguenther at suse dot de
2020-05-14 11:46 ` redi at gcc dot gnu.org
2020-05-14 11:51 ` rguenther at suse dot de
2020-05-14 12:01 ` redi at gcc dot gnu.org
2020-05-14 12:02 ` redi at gcc dot gnu.org
2020-05-14 12:05 ` redi at gcc dot gnu.org
2020-05-19 22:23 ` cvs-commit at gcc dot gnu.org
2020-05-23  8:18 ` redi at gcc dot gnu.org
2020-07-09  8:49 ` avi@cloudius-systems.com
2020-07-09  9:14 ` cvs-commit at gcc dot gnu.org
2020-07-09  9:14 ` redi at gcc dot gnu.org

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