Re: [OpenModelThreadGroup]Spike of threads on start-up

Felix Schumacher <[email protected]> Tue, 24 Sep 2024 17:18:24 +0200
Newsgroups	gmane.comp.jakarta.jmeter.user
Message-ID	<[email protected]>
I think you found a bug and I opened 
https://github.com/apache/jmeter/issues/6352

The workaround of adding "pause(6 min)" to your setup should help you 
out till we fixed the bug.

So, change "rate(0) random_arrivals..." to "pause(6 min) rate(0) 
random_arrivals..." and you can spend six minutes in your setup thread 
group without getting a sample storm at the start of OMTG after setup 
has finished.

Felix

Am 24.09.24 um 12:26 schrieb Felix Schumacher:
>
> Could you try to compensate for the thread setup group by adding a 
> pause(6 min) (or even seven minutes) at the start of your OMTG? I 
> suspect, that the start times for the threads are calculated from the 
> beginning of the test instead of after the setup groups.
>
> Felix
>
> Am 24.09.24 um 12:01 schrieb Liliane et Robert Bourgault du Coudray:
>> Ah, this is because I have a "Setup Thread Group" using the standard 
>> Thread Group and running for 5 to 6 minutes to do some initial data 
>> setup on the system.
>> And then the OMTG will kick in.
>> I have not shown the threads of this Setup Thread Group in the graph, 
>> only the OMTG sequence.
>>
>> Le mar. 24 sept. 2024 à 16:37, Felix Schumacher 
>> <[email protected]> a écrit :
>>
>>     Why is the spike at 06:23 (seconds? minutes?). Could it be, that
>>     something is holding back your threads and releases them all at one?
>>
>>     If there is a lot of time at the beginning of the test, where
>>     seemingly nothing happens, I would take a few thread dumps on the
>>     JMeter side and look at those.
>>
>>     Felix
>>
>>     Am 19.09.24 um 03:36 schrieb Robert Bourgault du Coudray:
>>>
>>>     Hi,
>>>     I am seeing a spike of threads on start-up, which I think is
>>>     abnormal.
>>>
>>>     For instance, I have set an Open Model Thread Group with
>>>     following parameters:
>>>
>>>     / * Rampup-up time over 1 min */
>>>
>>>     rate(0) random_arrivals(1 min) rate(30/min)
>>>
>>>     /* Test  for 30 mins */
>>>
>>>     random_arrivals(30 min) rate(30/min)
>>>
>>>     With these settings, we are seeing a spike of threads up to 160
>>>     on start-up before the system stabilises to a more reasonable
>>>     rate afterwards (see attachment).
>>>
>>>     This is causing false positives on our SUT.
>>>
>>>     Can you please suggest any workarounds or fixes?
>>>
>>>     Thank you
>>>
>>>     *Robert Bourgault du Coudray*
>>>     Senior Quality Engineer | Bankwest Technology
>>>     Level 14C Bankwest Place 300 Murray Street Perth WA 6000
>>>     (08) 9369 9487   |   0468 770 721
>>>     [email protected]
>>>     bankwest.com.au <http://www.bankwest.com.au/>
>>>
>>>     *Bankwest acknowledges the Traditional Owners of the lands
>>>     across Australia as the continuing custodians of Country and
>>>     Culture. We pay our respect to First Nations peoples and their
>>>     Elders, past and present. *
>>>
>>>
>>>     _______________________________________________________________________________
>>>     Unencrypted electronic mail is not secure and may not be authentic.
>>>     If you have any doubts as to the contents please telephone to
>>>     confirm.
>>>
>>>     This electronic transmission including any attachments is
>>>     intended only
>>>     for those to whom it is addressed. It may contain copyright
>>>     material or
>>>     information that is confidential, privileged or exempt from
>>>     disclosure by law.
>>>     Any claim to privilege is not waived or lost by reason of
>>>     mistaken transmission
>>>     of this information. If you are not the intended recipient you
>>>     must not
>>>     distribute or copy this transmission and should please notify
>>>     the sender.
>>>     Your costs for doing this will be reimbursed by the sender.
>>>
>>>     We do not accept liability in connection with computer virus,
>>>     data corruption,
>>>     delay, interruption, unauthorised access or unauthorised amendment.
>>>     _______________________________________________________________________________
>>>
>>>
>>>
>>>
>>>     This email has been scanned by the Microsoft Exchange Online
>>>     Protection cloud service.
>>>     For more information please visit Exchange Online Protection
>>>     <https://www.microsoft.com/en-au/microsoft-365/exchange/exchange-email-security-spam-protection>
>>>
>>>
>>>
>>>     ---------------------------------------------------------------------
>>>     To unsubscribe, e-mail:[email protected]
>>>     For additional commands, e-mail:[email protected]
>>
OpenPGP_0xEA6C3728EA91C4AF.asc (application/pgp-keys, 6.1 KB)
OpenPGP_signature.asc (application/pgp-signature, 840 B)