[rrd-users] Can this script be optimised ?

[Pablo Sanchez]

[ Comments below, in-line ]

On 11/28/2012 07:23 AM, Simon Hobson wrote:
> [ trimmed ]
>
> this script seems to take a fair bit of resource, can anyone see any
> optimisation I've missed ?

Hi Simon,

When I do any optimization, I always instrument and prioritize the
slowest area of code.

Looking at the shell script below, there appear to be two areas of
optimization that you can change:

1) The while conditional check, and/or
2) The setting of UpdateVal

I'll assume the `rrdtool' can't be changed (e.g. the disk the .rrd is
on isn't the bottleneck.

Given the above, where's the slowness?  Is it 1) or 2)?

>
>
> #!/bin/bash
> # Get traffic count from interface counters of global interface
>
> EndTime=$(( `/bin/date +%s` + 58 ))
> HostName=$( /usr/bin/head -1 /etc/hostname )
> while [ $( /bin/date +%s ) -lt ${EndTime} ]
> do
>     UpdateVal=$( /sbin/ifconfig ethext | \
>       /bin/grep 'RX bytes' | \
>       /bin/sed -r -e 's/^.*RX bytes:([0-9]+) .* TX bytes:([0-9]+) .*$/\1:\2/' )
>     /usr/bin/rrdtool update ${HostName}/global.rrd --daemon w.x.y.z
> "N:${UpdateVal}"
>     sleep 2
> done
>
>

Cheers,
-- 
Pablo Sanchez - Blueoak Database Engineering, Inc
Ph:    819.459.1926         Blog:  http://pablo.blog.blueoakdb.com
Fax:   760.860.5225 (US)