Page 1 of 1

Another PCQ clarification thread

Posted: Wed Jan 10, 2018 6:26 am
by rwrocket
I have been revisiting PCQ queues recently and have found it difficult to find a straight forward formula or definitive answer on how to calculate the PCQ settings.

I will give two different examples just so I can get it clear in my head.
I have so far left the default pcq-limit of 50Kib and 2000Kib on the pcq-total-limit as I believe that is supposed to be the pcq-limit X number of concurrent users and seeing as we only have about 9 but about 50 DHCP leases I am not sure if I should change this or not.


Example A:
A small office scenario where there is 30Mbps download and 20Mbps upload
There is about 50 DHCP leases but only about 9 active PCs/Users through-out the day
subnet is a /24
I am currently testing :

* name="pcq-down-30M" kind=pcq pcq-rate=30M pcq-limit=50KiB pcq-classifier=dst-address pcq-total-limit=2000KiB pcq-burst-rate=0 pcq-burst-threshold=0 pcq-burst-time=10s pcq-src-address-mask=32 pcq-dst-address-mask=32
pcq-src-address6-mask=128 pcq-dst-address6-mask=128
* name="pcq-upload-20M" kind=pcq pcq-rate=20M pcq-limit=50KiB pcq-classifier=src-address pcq-total-limit=2000KiB pcq-burst-rate=0 pcq-burst-threshold=0 pcq-burst-time=10s pcq-src-address-mask=32 pcq-dst-address-mask=32
pcq-src-address6-mask=128 pcq-dst-address6-mask=128

* name="LAN-WAN" target=192.168.38.0/24 parent=none packet-marks="" priority=8/8 queue=pcq-upload-20M/pcq-down-30M limit-at=0/0 max-limit=20M/30M burst-limit=0/0 burst-threshold=0/0 burst-time=0s/0s bucket-size=0.1/0.1

It is my understanding that given only a single user online and every other user isolated when performing a speedtest results should reach somewhere close to 30down 20 up with these settings (assuming 30/20 bandwidth was originally available which it is)

Example B
60 Concurrent users
200Mbps bandwidth
Is it still ok to use the default 50Kib pcq-limit?
What would other settings be etc?

thanks in advance for input

Re: Another PCQ clarification thread

Posted: Fri Jan 12, 2018 1:09 am
by rwrocket
*bump*

hate having to bump my own thread but more often than not my posts get 0 replies, maybe I am asking too difficult questions?

Re: Another PCQ clarification thread

Posted: Fri Jan 12, 2018 9:29 am
by chechito
on pcq queue you can change "pcq-rate=30M" for "pcq-rate=0" is not necesary to specify this value becaus you are limiting on the simple queue, this value is used t o limit per host speed

values for 30m/20m i will recommend:
download: limit 999 and total limit of 99999
upload: limit 999 and total limit of 99999

for 200M/200M i will recommend
download: limit 9999 and total limit of 999999
upload: limit 9999 and total limit of 999999

if you find upload trafic too burty showing bigger speeds or speedtest showing wrong results bigger than your upload connection try lowering your upload limit by one digit


max-limit values on simple queue must be 90%-to 80% of your real usable bandwidth to queuing work properly

Re: Another PCQ clarification thread

Posted: Wed Jan 17, 2018 7:17 am
by rwrocket
on pcq queue you can change "pcq-rate=30M" for "pcq-rate=0" is not necesary to specify this value becaus you are limiting on the simple queue, this value is used t o limit per host speed

values for 30m/20m i will recommend:
download: limit 999 and total limit of 99999
upload: limit 999 and total limit of 99999

for 200M/200M i will recommend
download: limit 9999 and total limit of 999999
upload: limit 9999 and total limit of 999999

if you find upload trafic too burty showing bigger speeds or speedtest showing wrong results bigger than your upload connection try lowering your upload limit by one digit


max-limit values on simple queue must be 90%-to 80% of your real usable bandwidth to queuing work properly
Thanks for the reply

What is the formula/basis of these numbers? as it looks a bit like guess work?
However I will give them and a try and see what the results are