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From: Dan Gora <dg@adax.com>
To: Mattias Rönnblom <mattias.ronnblom@ericsson.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
	David Marchand <david.marchand@redhat.com>,
	 Jerin Jacob <jerinjacobk@gmail.com>
Subject: Re: [dpdk-dev] [PATCH v4 0/2] eal: choose initial PRNG seed source at runtime
Date: Mon, 29 Jun 2020 15:01:13 -0300
Message-ID: <CAGyogRYA1qOhwhRJyTcbK=Xox1r1NThFsTvsmbeoLYux2-TVNw@mail.gmail.com> (raw)
In-Reply-To: <7c4c38bb-ecec-8cad-1220-c6a057574e0e@ericsson.com>

On Mon, Jun 29, 2020 at 6:32 AM Mattias Rönnblom
<mattias.ronnblom@ericsson.com> wrote:
>
> On 2020-04-23 01:42, Dan Gora wrote:
> > Hi All,
> >
> > The following patches updates the rte_random subsystem to dynamically find
> > the best source of the initial seed to the PRNG at run time.
> >
> > The first patch enables dynamic checking for the rdseed instruction and
> > removes the requirement for it on the execution system.  It also ensures
> > that the code to use the rdseed instruction is generated, even if the host
> > compilation system does not support it (on x86 systems).
> >
> > The second patch emulates the getentropy() glibc function by reading bytes
> > from /dev/urandom.  This removes an unnecessary dependency on glibc 2.25.
> >
> > v4:  Note that emulating getentropy by reading from /dev/urandom should
> > never fail, so now the question is if we should just remove the rdseed
> > method entirely since it's x86 only?  Should we remove the fallback to
> > rte_get_tsc_cycles()?
> >
> > Thanks
> > Dan
> >
> > -----
> > v2:
> > * Fix patch apply issue.
> > * dlclose() handle if dlsym() fails in __rte_getentropy().
> >
> > v3:
> > * Fix error checking of dlsym() in __rte_getentropy().
> > * Style changes recommended by Mattias.
> >
> > v4:
> > * Replace dlopen/dlsym method with reading from /dev/urandom.
> > * Try rdseed method before getentropy() method since the
> >    latter should never fail.
>
>
> I see no reason to prefer rdseed over the kernel.

Let me give you a good reason.  The reason that this change was done...

Since rte_getentropy() is now available on all systems (with these
patches) and cannot fail. rdseed can either 1) go before
rte_getentropy() or 2) be completely removed.

What do you recommend?

thanks
dan

  reply	other threads:[~2020-06-29 18:01 UTC|newest]

Thread overview: 47+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-21 19:54 [dpdk-dev] [PATCH " Dan Gora
2020-04-21 19:54 ` [dpdk-dev] [PATCH 1/2] eal: check for rdseed at run time for random seed Dan Gora
2020-04-22  8:22   ` Mattias Rönnblom
2020-04-21 19:54 ` [dpdk-dev] [PATCH 2/2] eal: resolve getentropy " Dan Gora
2020-04-21 21:03   ` Stephen Hemminger
2020-04-21 21:08     ` Dan Gora
2020-04-22  8:28   ` Mattias Rönnblom
2020-04-22 17:44     ` Dan Gora
2020-04-22 20:14       ` Mattias Rönnblom
2020-04-22 20:35         ` Dan Gora
2020-04-23 10:04           ` Luca Boccassi
2020-04-23 17:38             ` Dan Gora
2020-04-27 12:44               ` Luca Boccassi
2020-04-27 16:57                 ` Dan Gora
2020-04-30  8:41                   ` Luca Boccassi
2020-04-30 20:43                     ` Dan Gora
2020-05-01 10:33                       ` Luca Boccassi
2020-05-01 21:05                         ` Dan Gora
2020-05-04  8:04                           ` Mattias Rönnblom
2020-05-04 14:13                             ` Dan Gora
2020-05-04 14:19                               ` Dan Gora
2020-06-02  5:10                                 ` Dan Gora
2020-06-09 15:37                                   ` Dan Gora
2020-06-10  8:15                                     ` Thomas Monjalon
2020-06-10  8:33                                       ` Luca Boccassi
2020-06-10  8:07                               ` Thomas Monjalon
2020-04-23 12:36           ` Mattias Rönnblom
2020-04-23 17:27             ` Dan Gora
2020-04-21 20:41 ` [dpdk-dev] [PATCH v2 0/2] eal: choose initial PRNG seed source at runtime Dan Gora
2020-04-21 20:41   ` [dpdk-dev] [PATCH v2 1/2] eal: check for rdseed at run time for random seed Dan Gora
2020-04-21 20:41   ` [dpdk-dev] [PATCH v2 2/2] eal: resolve getentropy " Dan Gora
2020-04-22 18:15 ` [dpdk-dev] [PATCH v3 0/2] eal: choose initial PRNG seed source at runtime Dan Gora
2020-04-22 18:15   ` [dpdk-dev] [PATCH v3 1/2] eal: check for rdseed at run time for random seed Dan Gora
2020-04-22 18:15   ` [dpdk-dev] [PATCH v3 2/2] eal: resolve getentropy " Dan Gora
2020-04-22 23:42 ` [dpdk-dev] [PATCH v4 0/2] eal: choose initial PRNG seed source at runtime Dan Gora
2020-04-22 23:42   ` [dpdk-dev] [PATCH v4 1/2] eal: check for rdseed at run time for random seed Dan Gora
2020-04-22 23:42   ` [dpdk-dev] [PATCH v4 2/2] eal: emulate glibc getentropy for initial " Dan Gora
2020-04-23  2:39     ` Stephen Hemminger
2020-04-23 17:42       ` Dan Gora
2020-06-29  9:30     ` Mattias Rönnblom
2020-06-29 17:57       ` Dan Gora
2020-06-29 20:57         ` Mattias Rönnblom
2020-06-29  9:32   ` [dpdk-dev] [PATCH v4 0/2] eal: choose initial PRNG seed source at runtime Mattias Rönnblom
2020-06-29 18:01     ` Dan Gora [this message]
2020-06-29 18:04       ` Dan Gora
2020-06-29 21:05       ` Mattias Rönnblom
2020-06-29 21:14         ` Dan Gora

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