> On Jul 24, 2015, at 9:11 AM, Leif Hedstrom <[email protected]> wrote:
>
>>
>> On Jul 24, 2015, at 3:16 AM, Susan Hinrichs
>> <[email protected]> wrote:
>>
>> Hello,
>>
>> Another latent cross-thread race condition has become very active in our
>> environment (TS-3797). Given that we just spent time within the last month
>> squashing another cross thread race condition (TS-3486) that was active in
>> several environments, Alan and I would like to step back and try to reduce
>> the cross thread impact of the global session pools.
>>
>> I wrote up our thoughts and plan for implementation. Given that threading
>> and race conditions are always tricky, I'd appreciate more eyes looking for
>> flaws in our approach or suggestions for alternatives.
>>
>> https://cwiki.apache.org/confluence/display/TS/Threading+Issues+And+NetVC+Migration
>
>
>
> My gut reaction to this is that this makes our efforts for NUMA / thread
> affinity very, very difficult to achieve. The goal is to avoid memory
> migrating cross NUMA sockets, to avoid QPI traffic. This would encourage the
> opposite unless I misread it ? It also obviously violates the original design
> goals, where VCs do *not* migrate.
Also, William Bardwell made an attempt to do these VC migrations long ago, and
it did not work well. That was in fact the reason why the per-thread session
pools where implemented.
See the patches / discussions on
https://issues.apache.org/jira/browse/TS-880
The Subject of that Jira is somewhat confusing, but it’s the same issue: A KA
connection to origin is used by client VCs on different threads that the origin
connections.
— Leif
