Hi Saku, > So 80% of time, work needed to compete for access to the CPU.
Yes. I hesitated because when I compare the ping results and vFP CPU utilization plus microkernel threads CPU usage during the route churn and without the route churn, then while CPU utilization clearly increased, it did not *seem* to increase enough to explain such drastic RTT fluctuation and even some packet loss. On the other hand, I have absolutely no idea how the microkernel schedules its processes/threads or how the virtualized forwarding plane distributes those four CPU cores it has. Graphical representation of the output of "show linux cpu usage" PFE CLI command can be seen here: https://i.imgur.com/f1vMAn4.png and https://i.imgur.com/vm5nr2S.png. First graph represent CPU cores utilization under normal conditions. Second graph represents CPU cores utilization during the route churn. Those four CPU cores are the host machine CPU cores where the quemu virtualizes the forwarding plane. > If I understood your explanation right (I may not have): At this point, I was focusing on the ICMP "echo request" message only. Network topology seen from Linux is following: vcp-vmx1[vcp-int-vmx1] <-> [2]br-int-vmx1[3] <-> [vfp-int-vmx1]vfp-vmx1[ge-0.0.9-vmx1] vcp-vmx1 is RE running Junos and vcp-int-vmx1 is em1 interface in Junos. br-int-vmx1(Linux bridge) serves the similar purpose to integrated switch in SCB seen with the "show chassis ethernet-switch" command in Junos. vfp-int-vmx1 is the line-card Ethernet interface used by microkernel to communicate with RE. ge-0.0.9-vmx1 represents the ge-0/0/9 seen in Junos which is directly connected to TAP device ge-0.0.9-vmx1: martin@PC:~$ sudo ethtool -i ge-0.0.9-vmx1 driver: tun version: 1.6 firmware-version: expansion-rom-version: bus-info: tap supports-statistics: no supports-test: no supports-eeprom-access: no supports-register-dump: no supports-priv-flags: no martin@PC:~$ So when I execute the "ping 10.55.55.1 source 10.55.55.2 count 1" command in RE, then the ICMP "echo request" package travels out from the RE via vcp-int-vmx1 interface, through the Linux bridge into the line-card via vfp-int-vmx1 and then to ge-0.0.9-vmx1 in host machine which has 10.55.55.1 configured. I did packet capture simultaneously on vfp-int-vmx1 and ge-0.0.9-vmx1 interfaces. Martin _______________________________________________ juniper-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/juniper-nsp
