Re: [dpdk-dev] [PATCH v3] usertools: fix pmdinfo parsing

[Bruce Richardson <bruce.richardson@intel.com>]

On Wed, Nov 04, 2020 at 05:48:27PM +0100, David Marchand wrote:
> On Wed, Nov 4, 2020 at 5:36 PM Bruce Richardson
> <bruce.richardson@intel.com> wrote:
> >
> > On Wed, Nov 04, 2020 at 04:57:21PM +0100, David Marchand wrote:
> > > This script inspects an ELF file (binary or shared library) and its
> > > linked dependencies by following DT_NEEDED tags.
> > > So far a simple librte_pmd prefix was used as a filter to only parse
> > > DPDK drivers dependencies.
> > > While the reason is not clear from the commitlog of the patch that
> > > introduced this filter, it was probably added for performance reasons,
> > > since going through all dependencies can be quite long.
> > > Testing with a DPDK built before the driver name changes:
> > > - running the script takes ~0.3s with the filter,
> > > - running the script takes ~9s without the filter,
> > >
> > > Now that we changed the driver library names, it becomes more difficult
> > > to identify only DPDK drivers, but we can just filter on the librte_
> > > prefix to identify DPDK libraries: the script later checks for the
> > > PMD_INFO_STRING string in .rodata and it is enough to differentiate the
> > > DPDK drivers from the other DPDK libraries.
> > > A debug message was logged for each inspected file, it gives no useful
> > > information and is removed.
> > >
> > > Fixes: a20b2c01a7a1 ("build: standardize component names and defines")
> > >
> > > Signed-off-by: David Marchand <david.marchand@redhat.com>
> > > Acked-by: Robin Jarry <robin.jarry@6wind.com>
> > > ---
> > > Changelog since v2:
> > > - revisited the issue and simplified to only filter on librte_ prefix,
> > >
> >
> > Given you provided some original perf numbers of 0.3 vs 9 seconds above,
> > rather than leave us all in suspense :-), can you perhaps provide the
> > numbers for this version too.
> 
> Ah ah, yes, thought I had put it.
> I have values in the 0.40/0.50s range.
> 
Sounds good.

Acked-by: Bruce Richardson <bruce.richardson@intel.com>