Hi, I am seeing something a bit strange with RCU where it is trying to start a GP twice from a CPU even though no new CB was queued on that CPU. It is quite possible that I'm missing something. Anyway, I wrote a patch to add some tracing when CBs are queued into the segcb. I am planning to post this trace patch later. The trace in the link below shows CPU2 queuing around 5 CBs, which then gets accelerated at 5.192123. The GP thread running on CPU3 starts a new GP. Now the CPU2 softirq runs again (roughly 1ms after the previous acceleration). The softirq runs probably because the GP thread is expecting a QS report from CPU 2. When the CPU2's softirq runs though, it does an acceleration again which triggers a second new GP start. This seems a bit unnecessary AFAICS - because the need for GP *832 was already recorded which is all CPU2 should really be caring about right? Here is the trace: https://pastebin.com/raw/AYGzu1g4 Thanks, - Joel
