Monitor CPU level

[smsc_1]

Hi,
I just perform a check on ES40 OpenVMS system with following command:

$ monitor cluster /average /summary

Result on cluster was:
CPU Busy 0 25 50 75 100|
+----+----+----+----+|
NODE11 45 |aaaaaaaaa |
NODE12 41 |aaaaaaaa |
NODE13 35 |aaaaaaa |
| |
| |
| |

ES40 has 4 CPU onboard...

Our support says us that 50% was ONLY for ONE CPU

Is it real value for ONE CPU??

Thanks

[Wim Van den Wyngaert]

It's the average value for all cpu's together. So 50% can be 25% + 75% OR 50% + 50%.

Wim

[Volker Halle]

smsc,

if you want to look at the utilisation of individual CPUs in your ES40 nodes, you can use MONITOR MODE/CPU

Note that when a SMP system shows a high CPU usage and especially if one CPU is always at 100% CPU usage, this could indicate a looping process, i.e. a process in a tight loop just consuming CPU cycles.

Volker.

[Jess Goodman]

If you only want to monitor one ES40 you would probably be better served with one of these two commands:

$ MONITOR SYSTEM /AVERAGE/SUMMARY
or if you want to see idle % instead:
$ MONITOR MODES /AVERAGE /SUMMARY

Add /NODE=NODEnn to the end of the command if you are not on that node currently.

The CPU display for this output will be for all four CPUs so the maximum display value would be 400%. If it shows 50% that could be 50% of one CPU with the other 3 idle, or 25% of two CPUs with 2 idle, etc.

[Andy Bustamante]

Besides the monitor notes, consider using T4 from HP http://h71000.www7.hp.com/openvms/products/t4/index.html to drill down into system performance. You also get the ability to log and review trends.

For a very nice write up of free performance monitoring tools see: http://www.parsec.com/general/FreePerformanceTools.pdf . This was web seminar presented by the Parsec group

Andy Bustamante

[smsc_1]

Thanks to all for reply! ^_^

I just want to clarify better my question.
For the XMAS holidays our AlphaServer got a very big TCP/SS7 traffic.

My goal was to know if one ES40 can handle that traffic.

According to your reply, if I perform following command:
MONITOR SYSTEM /AVERAGE/SUMMARY
I should see value of ONE CPU (the first). That's clear, but why I got 100% as limit (and not 400%)??

How can I see (in case first CPU got 100%) other CPU LEVEL??


Anyway! Happy XMAS to all!

[Volker Halle]

smsc,

if the MONITOR display you're using shows 400% on the x-axis, this will be the utilization for 4 CPUs, one fully loaded CPU will contribute 100%. Some of the other displays may only show 100% on the x-axis, so if you have 4 CPUs in such a system, one CPU, if it is completely busy, will only contribute 25% to the overall value in such a case.

If you are interested in the CPU load of the individual CPUs in one system, use MONITOR MODE/CPU, the display will cycle through the individual CPUs and show you their usage, as far as I remember.

Volker.

[Hoff]

So why not ask your support staff for help? Seriously. One obvious potential inference here is that there are some trust issues here, and these are a class of issues that tend to get worse through use of ITRC. Not better.

From the other side of this equation -- from the view from your support staff -- finding users running MONITOR has often been a red flag for latent system and performance issues. Both for actual performance issues, and for performance perceptions. And finding users over here in ITRC asking these sorts of questions is another red flag for site issues.

I'd encourage you to work directly with your support staff, and to get TDC and T4 loaded on this system, and to perform a systematic approach toward performance. Toward long-term collection of performance data. And toward building up trust.

Sure, knowing about spikes can be useful.

Knowing longer-term patterns and particularly around increasing load -- whether it's a pre-holiday telephony spikes year to year, or a longer-term increase in baseline performance, is invaluable. A one-shot MONITOR doesn't tell you much. What's more interesting is year over year and peak to peak; a trend.

System trends are not easily visible with isolated and with rogue MONITOR passes. And sometimes an unexpected MONITOR itself can stuff up the data collection processes; one site I dealt with had a performance problem that (and I kid you not) turned out to be eight or ten folks all running gonzo MONITOR passes. And FWIW, TDC and T4 are far better at displaying data than is an isolated MONITOR. And support is in a better place to help with long-term performance monitoring.

Stephen Hoffman
HoffmanLabs LLC

[comarow]

Actually, there's another way to
look at how well the cpu is being used.

Look at the CPU Queue length. If on the average there is more than one job waiting
for the CPU, then by definition you have
a cpu bottleneck.

$Monitor System
You will see a column called COM

If that sits above 1 for any length of time,
it means that jobs are waiting for CPU time.

[smsc_1]

Thanks to all,
with:
MONITOR SYSTEM /AVERAGE/SUMMARY
I got exactly what I want!

CPU busy MAX value=400, this means that with supplied command I can monitor ALL CPU.

Only one field was not clear:

+ Buffered I/O Rate (1538)-+
|aaaaaaaaaaaaaaaaaaaaaaaaaa|
0+--------------------------+ 500
|aaaaaaaaaaaaaaaaaaaaaaaaaa|
+--------------------------+
Cur Top: VIQ_NTP_V351 (1451)


As you can see values goes from 0 to 500 and actual value was 500... What does it mean: Buffered I/O Rate (1538)
Is it a DANGER VALUE??

Happy holidays to all! ^_^