Re: [dpdk-dev] [dpdk-stable] [PATCH] eal: fix querying DPDK version at runtime

[Thomas Monjalon <thomas@monjalon.net>]

05/02/2021 22:26, Bruce Richardson:
> On Fri, Feb 05, 2021 at 09:05:43PM +0100, Thomas Monjalon wrote:
> > 05/02/2021 20:39, Bruce Richardson:
> > > For using a DPDK application, such as OVS, which is dynamically linked, the
> > > DPDK version in use should always report the actual version, not the
> > > version used at build time. This incorrect behaviour can be seen by
> > > building OVS against one version of DPDK and running it against a later
> > > one. Using "ovs-vsctl list Open_vSwitch" to query basic info, the
> > > dpdk_version returned will be the build version not the currently running
> > > one - which can be verified using the DPDK telemetry library client.
> > > 
> > >   $ sudo ovs-vsctl list Open_vSwitch | grep dpdk_version
> > >   dpdk_version        : "DPDK 20.11.0-rc4"
> > > 
> > >   $ echo quit | sudo dpdk-telemetry.py
> > >   Connecting to /var/run/dpdk/rte/dpdk_telemetry.v2
> > >   {"version": "DPDK 21.02.0-rc2", "pid": 405659, "max_output_len": 16384}
> > 
> > Nice demonstration.
> > 
> > >  __rte_experimental
> > >  int
> > > -rte_telemetry_init(const char *runtime_dir, rte_cpuset_t *cpuset,
> > > +rte_telemetry_init(const char *runtime_dir, const char *rte_version, rte_cpuset_t *cpuset,
> > >  		const char **err_str);
> > 
> > It is changing the API.
> > As it is experimental, you just need to mention it in the release notes.
> 
> I don't think I actually need to mention it there, because this API is more
> "INTERNAL" than "EXPERIMENTAL". It's called automatically from
> rte_eal_init(). I've done up patch http://patches.dpdk.org/patch/87806/
> to correct this, including a RN addition. That should remove the need for a
> doc update for this patch.
> 
> > 
> > It is the fix. Do you think it should be merged quickly?
> > Or wait for 21.05?
> > 
> 
> I'm not sure either way to be honest. Given the bug has been around so
> long, it's not exactly urgent. On the other hand, to get the fix the user
> needs to rebuild their app, so having it sooner is nicer, and will mean it
> would make the next LTS point release. Overall, though, I'm fine whichever
> you decide.


There is not much help available to close 21.02, so I won't take any risk.
I'll merge this fix in 21.05.