Re: [dpdk-dev] [PATCH v2] eal: fix querying DPDK version at runtime

[David Marchand <david.marchand@redhat.com>]

On Tue, Feb 16, 2021 at 4:13 PM Bruce Richardson
<bruce.richardson@intel.com> wrote:
>
> 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}
>   -->
>
> To fix this, we need to convert the rte_version() function, and any other
> necessary parts of the rte_version.h, to be actual functions in EAL, not
> just inlines/macros. The only complication in doing so is that telemetry
> library cannot call rte_version() directly, and instead needs the version
> string passed in on init.
>
> Fixes: af75078fece3 ("first public release")
> Cc: stable@dpdk.org


> diff --git a/lib/librte_eal/include/rte_version.h b/lib/librte_eal/include/rte_version.h
> index f7a3a1ebc..2f3f727b4 100644
> --- a/lib/librte_eal/include/rte_version.h
> +++ b/lib/librte_eal/include/rte_version.h
> @@ -28,38 +28,47 @@ extern "C" {
>   * All version numbers in one to compare with RTE_VERSION_NUM()
>   */
>  #define RTE_VERSION RTE_VERSION_NUM( \
> -                       RTE_VER_YEAR, \
> -                       RTE_VER_MONTH, \
> -                       RTE_VER_MINOR, \
> -                       RTE_VER_RELEASE)
> +                       rte_version_year(), \
> +                       rte_version_month(), \
> +                       rte_version_minor(), \
> +                       rte_version_release())

It breaks SPDK and applications relying on RTE_VERSION in preprocessor
directives.
RTE_VERSION* macros should be left alone, and applications that need
the runtime value should call rte_version().

See logs in https://lab.dpdk.org/results/dashboard/results/results-uploads/test_runs/2f636aaf4ce244eba20844f9ff006033/log_upload_file/2021/3/dpdk_6857cb635821_2021-03-17_06-34-34_NA.zip

  CC lib/env_dpdk/pci_virtio.o
  CC lib/env_dpdk/pci_vmd.o
  CC lib/env_dpdk/pci_idxd.o
In file included from env_internal.h:42:0,
                 from pci_vmd.c:34:
/dpdk/build/include/rte_version.h:31:20: error: missing binary
operator before token "("
    rte_version_year(), \
                    ^
/dpdk/build/include/rte_version.h:25:36: note: in definition of macro
'RTE_VERSION_NUM'
 #define RTE_VERSION_NUM(a,b,c,d) ((a) << 24 | (b) << 16 | (c) << 8 | (d))
                                    ^
env_internal.h:49:5: note: in expansion of macro 'RTE_VERSION'
 #if RTE_VERSION < RTE_VERSION_NUM(19, 11, 0, 0)
     ^~~~~~~~~~~
In file included from env_internal.h:42:0,
                 from pci.c:34:
/dpdk/build/include/rte_version.h:31:20: error: missing binary
operator before token "("
    rte_version_year(), \
                    ^


-- 
David Marchand