[dpdk-users] rte_latency_stats (metrics library)

[dpdk-users] rte_latency_stats (metrics library)

[Arvind Narayanan]

Hi,

I am trying to play with latency statistics library (a wrapper around
rte_metrics lib). Whenever I try to retrieve values using
rte_latencystats_get(), all the stats are 0.
Even after rte_latencystats_update() still no effect on the stats.

Does this library need NIC driver support?
Any help would be appreciated.

Testing on l2fwd example app using:
-- DPDK 18.11
-- Mellanox ConenctX-5 EN 100G
-- Ubuntu 18.04
-- fw 16.24.1000

Thanks,
Arvind

Re: [dpdk-users] rte_latency_stats (metrics library)

[Pattan, Reshma]

> -----Original Message-----
> From: Arvind Narayanan [mailto:webguru2688@gmail.com]
> Sent: Saturday, August 3, 2019 11:27 PM
> To: users <users@dpdk.org>
> Cc: Pattan, Reshma <reshma.pattan@intel.com>
> Subject: rte_latency_stats (metrics library)
> 
> Hi,
> 
> I am trying to play with latency statistics library (a wrapper around
> rte_metrics lib). Whenever I try to retrieve values using
> rte_latencystats_get(), all the stats are 0.
> Even after rte_latencystats_update() still no effect on the stats.
> 
> Does this library need NIC driver support?
> Any help would be appreciated.
> 

Hi,

Do you have the traffic coming to l2fwd application?  If not you should have traffic running from the  traffic generator.


1)If you have traffic already, then can you also cross check by trying to fetch these latency stats using rte_metrics apis  instead of latency stats apis. 
(Or) equally you can run the dpdk-proc info secondary application to show you the stats (instead of you calling latency stats get and metrics get APIs).

2) Also, In DPDK, testpmd application has been updated to initiate latency stats calculation, and to see the stats you can run dpdk-procinfo secondary application alongside. 
This is to cross check that traffic is coming to dpdk application and stats are been calculated . You can try this second method if you don’t see success with l2fwd.

You can refer tespmd and dpdk-procinfo application codes to see how this is done.

Thanks,
Reshma