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Hi Adrian,

-----Original Message----- 
From: Adrian Sevcenco
Sent: Tuesday, June 18, 2019 9:35 AM
To: [log in to unmask]
Subject: cms.perf script - how to contribute

Hi! With the help of Oliver Freyermuth i rewrote the script
/usr/share/xrootd/utils/XrdOlbMonPerf
which in documentation is referenced as cms_MonPerf
http://xrootd.org/doc/dev410/cms_config.htm#_Toc8247264

in the form that can be seen here:
https://github.com/adriansev/bin-scripts/blob/master/cms_monPerf

w.r.t to old script i would have some questions :
1. what would be the proper name to have
+++So, cms_MonPerf is your preferred name. That's fine. I will simply stop 
documenting the old name.

2. i seen that both cms.perf and the script have some timing arguments
moreover the ols script is supposed to run in the loop ...
what is the relation between cms.pref int parameter and the "interval"
argument that the script is supposed to have?
+++Yes, the script needs to run in a loop and produce output at the 
frequency you specify as a parameter to the script. The int parameter is 
simply the estimated time between the program reporting something. The "int" 
value should be somewhat larger that the actual reporting time that you 
would specify as a parameter to the script. The reason is that the server 
uses the int value to determine if the reporting program is dead (i.e. not 
reporting) and needs to be restarted. Yes, I agree, none of that is 
explained in the doc.

3. is it really relevant for memory load to take into account the
buffers and cache?
+++No, not at all. I don't even think Linux takes that into account.

i assumed that :
1. -m <shmkey> option is something too old to be cared about
+++Correct. Forget about it.

2. -n netspeed have no meaning because either it is know directly
or, for virtio interfaces, even the human admin cannot determine it
(so for virtio interfaces the net load will be always 0)
As a generic network load measurement, packets per second averaged over the 
reporting interval (which can be computed) is a good indicator of how busy 
the interface is. I'd suggest simply doing that.

3. -I netintf this was also skipped as the net load will be taken as the
maximum of all physical up interfaces, with the assumption that on the
xrootd data server at least 1 interface is dedicated to xrootd server
and that is the most utilized.
+++Probably good enough here for the general cose.

the script make use only of awk and assumes linux.
+++That's fine. At least it will work virtually all Linux distros. Thanks a 
heap -- both of you!

As for getting it into the repo, simply create a pull request and I will 
merge it in.

Andy

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