Pradeep Padala wrote:
>>> Thanks for the clarifications Venu. I was measuring bandwidth by
>>> checking 'kstat -n' and as you mentioned, it's probably not
>>>
>> accurate.
>>
>>> Using 'netstat -k', I see that the bandwidth is capped correctly.
>>>
>> OK, while the stats may not be accurate, but the output from
>> netstat should not be very different from that calculated
>> using kstat. netstat gets the kstat values for vnic1, gets
>> the increment over the last time you read (via netstat) and
>> gives the average input/output for that time duration.
>> Perhaps you are not computing the values from kstat -n correctly?
>> I believe netstat uses the following logic:
>>
>> e.g for input:
>> input kbps = diff in (rbytes64 in kb) since prev read /
>> time since
>> last read;
>>
>> similarly for output.
>>
>
> That's exactly how I am measuring it. My python code looks like this
>
> timestamp = time.time()
> output = commands.getoutput('kstat -n vnic%d | grep bytes' %
> get_coid(coname)).split('\n')
> obytes = float(re.split('\s+', output[0])[2])
> rbytes = float(re.split('\s+', output[1])[2])
> return rbytes + obytes
>
> One question. The output of 'kstat -n vnic?' looks like this (I just
> rebooted, so most numbers are zero)
>
> module: unix instance: 0
> name: vnic1 class: flow
> crtime 109.436840067
> ierrors 0
> ipackets 268
> obytes 0
> oerrors 0
> opackets 0
> rbytes 24488
> snaptime 520.551380521
>
> module: vnic instance: 1
> name: vnic1 class: net
> brdcstrcv 1977
> brdcstxmt 0
> collisions 0
> crtime 484.32586088
> ierrors 2361
> ifspeed 200000000
> ipackets 268
> ipackets64 268
> multircv 0
> multixmt 0
> norcvbuf 0
> noxmtbuf 0
> obytes 0
> obytes64 0
> oerrors 0
> opackets 0
> opackets64 0
> rbytes 24488
> rbytes64 24488
> snaptime 520.552493729
> unknowns 0
>
> As you can see, there are a set of stats for 'flow' and for 'net'. Which
> ones should I be using? So far, I am taking the first set of stats.
>
I'd use the second set of stats but at least these 2 look the same.
Everything that is displayed in netstat -k is derived from kstats.
If you want to avoid the curses stuff, you could try a form of
dladm show-vnic with -s (for stats) and -i (for interval).
-Mike
