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From: Stephen Hemminger <stephen@networkplumber.org>
To: Dan Gora <dg@adax.com>
Cc: "Sanford, Robert" <rsanford@akamai.com>,
	"users@dpdk.org" <users@dpdk.org>
Subject: Re: meson options - build vs target machine cpuflags question
Date: Thu, 10 Mar 2022 17:18:54 -0800
Message-ID: <20220310171854.272f459b@hermes.local> (raw)
In-Reply-To: <CAGyogRaCtBxrPZDN0PqNTwCmxWnH2fUriKNLOwGQqOVU34g8xg@mail.gmail.com>

On Thu, 10 Mar 2022 19:54:48 -0300
Dan Gora <dg@adax.com> wrote:

> On Thu, Mar 10, 2022 at 11:46 AM Sanford, Robert <rsanford@akamai.com> wrote:
> >
> > Hello All,
> >
> > We build a DPDK 21.05 app on Intel x86 machines with RDSEED in cpuflags, and may run it on machines *without* RDSEED.
> > This results in a fatal error ...
> > ERROR: This system does not support "RDSEED".
> > Please check that RTE_MACHINE is set correctly.
> > EAL: FATAL: unsupported cpu type.
> >
> > I try adding -Dplatform=haswell when running meson, (because gcc man page indicates that haswell is last arch w/o RDSEED) but get the same result.
> > Until we resolve it, our workaround is changing the error-out in rte_cpu_is_supported() to just print a warning and continue.
> > We don't have direct access to automated build machines, we go through change request processes, and so we can't rapidly try too many things.
> >
> > Is there a better meson option, such as machine=haswell, or something else that will work?
> >
> > Thanks in advance,
> > Robert Sanford  
> 
> I tried four times to get a simple fix for this (and the lack of
> getentropy() on older glibc) to determine the entropy source at run
> time and got nothing but an endless raft of shit and ridiculous
> criticisms that I completely gave up trying to contribute to DPDK ever
> again.
> 
> The DPDK developers think that it's your responsibility to have a
> separate build system for each of your target systems and platforms
> and that if you don't you're basically a big dummy.
> 
> Don't believe me?  Go look through the archives:
> 
> "[PATCH 2/2] eal: resolve getentropy at run time for random seed"
> "[PATCH v4 2/2] eal: emulate glibc getentropy for initial random seed".
> 
> I suggest that you just fork DPDK and use one of those patches and
> just maintain a separate DPDK tree.  That's what I did.  It's way
> easier than trying to get anything upstream.
> 
> thanks
> dan

The ideal solution would be able to use gcc function attributes and dyanmic
linking to do this at runtime - ie multiversion library.  But this opens a set
of different problems like compiler versions and testing.

  parent reply	other threads:[~2022-03-11  1:19 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-10 14:46 Sanford, Robert
2022-03-10 22:54 ` Dan Gora
2022-03-10 22:58   ` Dan Gora
2022-03-10 23:39     ` Sanford, Robert
2022-03-11  0:00       ` Dan Gora
2022-03-11  1:18   ` Stephen Hemminger [this message]
2022-03-11  2:45     ` Dan Gora
2022-03-11  3:01       ` Stephen Hemminger

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