topic Re: Packet Descriptor Atomic Size and Total Size what does number indicate?? in General Topics

Packet Descriptor Atomic Size and Total Size what does number indicate??

MP18 — Wed, 18 Dec 2019 05:04:53 GMT

Today we have routing issue that caused the Packet descriptor to go 100 and Caused the max CPU on 5220 to 100.

sh running resource-monitor ingress-backlogs show

few sessions using 42/% and 39%.

atomic shows 81% total 99

I had to clear the sessions quickly to bring these numbers down.

Then we fixed the routing.

Need to know what does numbers atomic and Total tell us about packet descriptor.?

is total mean total size of packet descriptor available?

atomic means usage?

sometimes i see total as low as 81%.

Re: Packet Descriptor Atomic Size and Total Size what does number indicate??

jdelio — Mon, 03 Feb 2020 20:21:36 GMT

I was able to search internally and discovered this about the Atomic meaning..

"These terms refer to the type of work queue from which the CPU core picked up the associated packet-processing task.

Atomic queues of work must be executed by a single CPU core. Orderable queues of work may be distributed among multiple CPU cores. (The root/etymological meaning of 'atomic' is indivisible (or more literally, non-cuttable)."

Total may mean just that, in reference to the entire queue.

Re: Packet Descriptor Atomic Size and Total Size what does number indicate??

MP18 — Wed, 05 Feb 2020 15:39:17 GMT

Hi Joe,

Many thanks for getting back to me with the info.

Sometimes only way to learn or get specific information from PA is via Internal channel.

I have seen few times escalation engineers are very good and the info they have is not available to public.

Regards