Messages in this thread | | | Date | Fri, 3 May 2013 17:53:40 +0200 | From | Sebastian Andrzej Siewior <> | Subject | Re: [PATCH RT] sched/workqueue: Only wake up idle workers if not blocked on sleeping spin lock |
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* Steven Rostedt | 2013-03-18 15:12:49 [-0400]:
>In -rt, most spin_locks() turn into mutexes. One of these spin_lock >conversions is performed on the workqueue gcwq->lock. When the idle >worker is worken, the first thing it will do is grab that same lock and >it too will block, possibly jumping into the same code, but because >nr_running would already be decremented it prevents an infinite loop. > >But this is still a waste of CPU cycles, and it doesn't follow the method >of mainline, as new workers should only be woken when a worker thread is >truly going to sleep, and not just blocked on a spin_lock(). > >Check the saved_state too before waking up new workers. > >Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Taking for v3.8-rt.
Sebastian
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