[j-nsp] Finding drops

[Jason Lixfeld]

Hey Adam, 

> On Jan 24, 2019, at 5:51 AM, <adamv0025 at netconsultings.com> <adamv0025 at netconsultings.com> wrote:
> 
> Is the test stream unidirectional please? -say from left (the mx1 side) to right (mx2 side) please? Or bidirectional please?

It’s been bi-directional, in that the Rx Tester is set to loopback. More or less only so I could see the number of packets received out the far side.  This tester won’t count ingress packets unless it’s in loopback mode, or actually running some test.

In any event, turning the loopback off doesn’t have any effect on the results.

> Now that you're looking at the right router. 
> Can you please run the: show pfe statistics traffic fpc 0 | match "cell|drops" 
> on mx1
> If it shows info cell drops then that means the PFE can't cope with the PPS rate.

No matches here.  As Saku eluded to.

> Since as Saku confirmed both interfaces et-0/0/2 and et-0/0/0 on mx1 are on the same PFE then the packet processing computational load for ingress and egress processing is not spread across two PFEs but rather executed on a single PFE which has to handle 200Gbps (100in+100out) worth of traffic @ 64bps, can't be bothered to calculate the pps rate there, but my guess is that the PFE can't handle the resulting PPS rate (as it is most likely above the PFE's overall (in+out) PPS budget) which is not that high on Gen3 (applies to most NPUs out there with 100g ports).
> 

> If the chip is rated for 800G(400in+400out) extrapolating from my notes on MPC7 testing the 204PFE then should cope with ~200in+~200out @64bit (if your traffic is bidirectional you'd be at the limit. 

Are there no specs published that provide the max number of pps @ 64 bytes the MPC7?

> -is the flow-control disabled on all interfaces involved with this test please? (we don't want the mx2 to send pause frames to et-0/0/0  on mx1 when it can't cope with the ingress PPS rate, skewing the results)  


It is disabled.

jlixfeld at mx1# wildcard range show interfaces et-0/0/[0,2] | display set | match flow
set interfaces et-0/0/0 ether-options no-flow-control
set interfaces et-0/0/2 ether-options no-flow-control

[edit]
jlixfeld at mx1# 

jlixfeld at mx2# wildcard range show interfaces et-0/0/[0,2] | display set | match flow 
set interfaces et-0/0/0 ether-options no-flow-control
set interfaces et-0/0/2 ether-options no-flow-control

[edit]
jlixfeld at mx2#