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Is ODL controller multi-threaded?

asked 2014-08-12 00:12:04 -0800

zhipengh gravatar image

OSGi itself could be multi-threaded, could controller be said the same ?

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Simple answer is yes. But we need more information/background to the question before giving a more useful answer :-). Controller is multi-threaded for many reasons. Just because it is multi-threaded... doesn't mean it is awesome. So, a better context will help answer the question appropriately.

Madhu ( 2014-08-12 23:01:21 -0800 )edit

Hi Madhu, thx for the reply. Let me ask this way, does odl controller (hydrogen release) support working with multiple switches at the same time ?

zhipengh ( 2014-08-13 07:06:09 -0800 )edit

Yes. of-course.

Madhu ( 2014-08-13 11:00:49 -0800 )edit

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answered 2014-08-17 17:39:27 -0800

zhipengh gravatar image

Madhu>>@zhipengh Yes. all the observations are valid. As we discussed, though we have multi-threading in place, it is NOT properly used and hence it was hunkered down to be using the same queue to avoid race-conditions and all the issues that you observed. More over, the AD-SAL code isn't designed for Reactive forwarding. Being a mostly proactive forwarding controller, the usage of a single processing thread isn't a huge bottleneck. But, as you said, the ODL controller's reactive forwarding case suffers from these limitations.

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answered 2014-08-13 11:02:07 -0800

Madhu gravatar image

Madhu >> Simple answer is yes. But we need more information/background to the question before giving a more useful answer :-). Controller is multi-threaded for many reasons. Just because it is multi-threaded... doesn't mean it is awesome. So, a better context will help answer the question appropriately.

zhipengh >> Hi Madhu, thx for the reply. Let me ask this way, does odl controller (hydrogen release) support working with multiple switches at the same time ?

Madhu >> Yes. of-course. :-)

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hey man tried to catch u on IRC but u weren't there. My question was actually a question from others. Someone ran some tests on ODL Hydrogen release and got these problems: "The incoming events from each switch handling by SwitchHandler using a single thread per switch. The events from all switched

zhipengh ( 2014-08-14 07:40:36 -0800 )edit

inserted into a common PriorityQueue and handled by another single thread." "The ODL is not thread safe so when we tried to change it to use multithreads(10) the controller was stuck. ArpHandler had a problem: time out on clustered memory infinity; the arp pkts send is too slow to allow a good

zhipengh ( 2014-08-14 07:43:21 -0800 )edit

multithreading" "In addition, there are a lot of sync issues between the services that reflects the performance as well as the throughput of odl. Some scenario raised dead locks" So are these old problems with Hydrogen on Threading, or persistent threading problems that ODL can't shake away ftm?THX!

zhipengh ( 2014-08-14 07:46:11 -0800 )edit

@zhipengh Yes. all the observations are valid. As we discussed, though we have multi-threading in place, it is NOT properly used and hence it was hunkered down to be using the same queue to avoid race-conditions and all the issues that you observed. More over, the AD-SAL code isn't designed for Reactive forwarding. Being a mostly proactive forwarding controller, the usage of a single processing thread isn't a huge bottleneck. But, as you said, the ODL controller's reactive forwarding case suffers from these limitations.

Madhu ( 2014-08-14 09:02:12 -0800 )edit

@Madhu THX for the clarification. Just to be clear, this is has to do with the implementation choice right? Or is this something has to do with OSGi? Do we have plans on fixing these problems?

zhipengh ( 2014-08-14 09:07:50 -0800 )edit
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Asked: 2014-08-12 00:12:04 -0800

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Last updated: Aug 17 '14