On Junos OS Evolved PTX platforms, systems may generate persistent warning logs during Class-of-Service (CoS) scheduler updates. The log message typically appears as:
%PFE-X: [Warn] Jcmn: CoS: SchedMap: Target Weight is Zero !!, Q:0 m-Rate:0 g-Rate:0 e-Rate:0 e-Weight:1 t-Rate:0
This occurs because the underlying ASIC maintains eight queues per interface by default. When a user configuration utilizes fewer than eight queues, the scheduler computation processes the unconfigured queues and triggers a warning due to a zero target rate.
Jan 2 14:47:21 Device-Name evo-aftmand-bt[19476]: [t:20788] [Warn] Jcmn: CoS: SchedMap: Target Weight is Zero !!, Q:0 m-Rate:0 g-Rate:0 e-Rate:0 e-Weight:1 t-Rate:0
Jan 2 14:47:23 Device-Name evo-aftmand-bt[19476]: [t:20788] [Warn] Jcmn: CoS: SchedMap: Target Weight is Zero !!, Q:0 m-Rate:0 g-Rate:0 e-Rate:0 e-Weight:1 t-Rate:0
Jan 2 14:53:35 Device-Name evo-aftmand-bt[19476]: [t:20788] [Warn] Jcmn: CoS: SchedMap: Target Weight is Zero !!, Q:0 m-Rate:0 g-Rate:0 e-Rate:0 e-Weight:1 t-Rate:0
Jan 2 14:53:36 Device-Name evo-aftmand-bt[19476]: [t:20788] [Warn] Jcmn: CoS: SchedMap: Target Weight is Zero !!, Q:0 m-Rate:0 g-Rate:0 e-Rate:0 e-Weight:1 t-Rate:0
Jan 2 14:53:37 Device-Name evo-aftmand-bt[19476]: [t:20788] [Warn] Jcmn: CoS: SchedMap: Target Weight is Zero !!, Q:0 m-Rate:0 g-Rate:0 e-Rate:0 e-Weight:1 t-Rate:0
Jan 2 14:53:38 Device-Name evo-aftmand-bt[19476]: [t:20788] [Warn] Jcmn: CoS: SchedMap: Target Weight is Zero !!, Q:0 m-Rate:0 g-Rate:0 e-Rate:0 e-Weight:1 t-Rate:0
Jan 2 14:59:50 Device-Name evo-aftmand-bt[19476]: [t:20788] [Warn] Jcmn: CoS: SchedMap: Target Weight is Zero !!, Q:0 m-Rate:0 g-Rate:0 e-Rate:0 e-Weight:1 t-Rate:0
Jan 2 14:59:51 Device-Name evo-aftmand-bt[19476]: [t:20788] [Warn] Jcmn: CoS: SchedMap: Target Weight is Zero !!, Q:0 m-Rate:0 g-Rate:0 e-Rate:0 e-Weight:1 t-Rate:0
This is a cosmetic issue. There is no impact on traffic forwarding, hardware performance, or service stability.
A software fix has been implemented in the Class-of-Service code to ignore unconfigured queues during scheduler parameter computations [Addressed by PR1805398 - https://prsearch.juniper.net/problemreport/PR1805398]. This ensures that the "Target Weight is Zero" warning is suppressed unless there is a genuine configuration error on an active queue.
Fixed Releases:
The fix has been verified and integrated into the following Junos OS Evolved releases (and all subsequent maintenance releases):
Workaround:
If an immediate upgrade is not feasible, we can filter these logs from getting reported, or the logs can be avoided by explicitly configuring a scheduler map for all eight available queues. However, as this is a cosmetic issue with no functional impact, an upgrade to a fixed release is the recommended long-term solution.