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

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

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.

/Bruce