From: Stephen Hemminger <stephen@networkplumber.org>
To: "Mattias Rönnblom" <hofors@lysator.liu.se>
Cc: dev@dpdk.org, "Morten Brørup" <mb@smartsharesystems.com>,
"Mattias Rönnblom" <mattias.ronnblom@ericsson.com>
Subject: Re: [PATCH v2] eal: allow setting random number generator seed
Date: Mon, 14 Sep 2026 09:46:56 -0700 [thread overview]
Message-ID: <20260914094656.3c9161e7@phoenix.local> (raw)
In-Reply-To: <bd0242b5-44d8-40c7-8928-4586f0191fe1@lysator.liu.se>
On Mon, 14 Sep 2026 13:29:22 +0200
Mattias Rönnblom <hofors@lysator.liu.se> wrote:
> Den 2026-09-12 kl. 18:16, skrev Stephen Hemminger:
> > Many performance tests use rte_rand() and the random number
> > can perturb the results. Add an ability to override the automatic
> > random seed on DPDK startup.
>
> There is a way to seed the PRNG already, rte_srand(). Why the tests
> can't use this?
>
> Provided the test results depend on something that use the PRNG before
> the test driver has had the opportunity to call rte_srand(), controlling
> the *initial* seed may be required.
>
> I don't think this feature should be controlled by an environment
> variable. There is no precedent for that. If this functionality is
> deemed useful, it should be an EAL command line option, it seems to me.
There are several tests already using rte_srand() so that is one option.
The choice of environment variable was to match the existing test harness
infrastructure that uses MALLOC_PERTURB to pre-seed malloc.
next prev parent reply other threads:[~2026-09-14 16:47 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-11 22:58 [RFC] eal: allow setting random number generator seed Stephen Hemminger
2026-09-12 6:26 ` Morten Brørup
2026-09-12 16:16 ` [PATCH v2] " Stephen Hemminger
2026-09-14 11:29 ` Mattias Rönnblom
2026-09-14 12:04 ` Konstantin Ananyev
2026-09-14 16:47 ` Stephen Hemminger
2026-09-14 16:46 ` Stephen Hemminger [this message]
2026-09-14 9:05 ` [RFC] " Marat Khalili
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