> -----Original Message----- > From: Van Haaren, Harry > Sent: Thursday, October 4, 2018 2:00 PM > To: Laatz, Kevin <kevin.la...@intel.com>; dev@dpdk.org > Cc: step...@networkplumber.org; gaetan.ri...@6wind.com; > shreyansh.j...@nxp.com; tho...@monjalon.net; Richardson, Bruce > <bruce.richard...@intel.com> > Subject: RE: [PATCH v2 00/10] introduce telemetry library > > > -----Original Message----- > > From: Laatz, Kevin > > Sent: Wednesday, October 3, 2018 6:36 PM > > To: dev@dpdk.org > > Cc: Van Haaren, Harry <harry.van.haa...@intel.com>; > > step...@networkplumber.org; gaetan.ri...@6wind.com; > shreyansh.j...@nxp.com; > > tho...@monjalon.net; Laatz, Kevin <kevin.la...@intel.com> > > Subject: [PATCH v2 00/10] introduce telemetry library > > > > This patchset introduces a Telemetry library for DPDK Service Assurance. > > This library provides an easy way to query DPDK Ethdev metrics. > > <snip> > > > Note: We are aware that the --telemetry flag is not working for meson > > builds, we are working on it for a future patch. Despite opterr being set > > to 0, --telemetry said to be 'unrecognized' as a startup print. This is a > > cosmetic issue and will also be addressed. > > > > --- > > v2: > > - Reworked telemetry as part of EAL instead of using vdev (Gaetan) > > - Refactored rte_telemetry_command (Gaetan) > > - Added MAINTAINERS file entry (Stephen) > > - Updated docs to reflect vdev to eal rework > > - Removed collectd patch from patchset (Thomas) > > - General code clean up from v1 feedback > > > Hi Gaetan, Thomas, Stephen and Shreyansh! > > > goto TL_DR; // if time is short :) > > > In this v2 patchset, we've reworked the Telemetry to no longer use the vdev > infrastructure, instead having EAL enable it directly. This was requested as > feedback to the v1 patchset. I'll detail the approach below, and highlight > some issues we identified while implementing it. > > Currently, EAL does not depend on any "DPDK" libraries (ignore kvargs etc > for a minute). > Telemetry is a DPDK library, so it depends on EAL. In order to have EAL > initialize > Telemetry, it must depend on it - this causes a circular dependency. > > This patchset resolves that circular dependency by using a "weak" symbol for > telemetry init, and then the "strong" version of telemetry init will replace > it when the library is compiled in.
Correction: we attempted this approach - but ended up adding a TAILQ of library initializers functions to EAL, which was then iterated during rte_eal_init(). This also resolved the circular-dependency, but the same linking issue as described below still exists. So - the same question still stands - what is the best solution for 18.11? > Although this *technically* works, it > requires > that applications *LINK* against Telemetry library explicitly - as EAL won't > pull > in the Telemetry .so automatically... This means application-level build- > system > changes to enable --telemetry on the DPDK EAL command line. > > Given the complexity in enabling EAL to handle the Telemetry init() and its > dependencies, I'd like to ask you folks for input on how to better solve > this? > > > TL_DR; > > I'll re-suggest the --vdev as an option. It might not be perfect, > but in my opinion it's a better solution than the v2 solution here... > > Input and suggestions welcome, as you know integration is coming > close so sooner is better! > > > Regards, -Harry
