Lockpages, events and timer assorted fixes#141
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- Move page locking (mlockall) to execute before setting thread parameters - Remove forced 'data->lock_pages = 0' override for SCHED_IDLE tasks, as locking pages and scheduling policies are orthogonal and should be configured separately by the user - This ensures page locking happens early in thread initialization The change ensures that when lock_pages is enabled, memory pages are locked before any scheduling policy changes occur, which is important for real-time applications that need deterministic memory access patterns. Especially for SCHED_DEADLINE, locking pages after starting the first iteration might cause deadline misses. Fixes: 5890dd3 ("rt-app: Reorder page locking to properly skip it for SCHED_OTHER/IDLE") Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
So it's easier to understand when a task is actually ready for entering the first actual phase. Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Otherwise timers might be skewed. Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
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The mlock reordering modifies (5890dd3). Locking pages whatever the scheduling policy makes sense to me but I'd like to know what @jan-kiszka thinks about it if it was only because of the data->lock_pages = 0 |
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In general, you don't need to lock pages before you actually start your workload - which might be much later than setting scheduling parameters. But the essence here is that, if you only have non-RT threads, you should not be bothered with page locking by default. In turn, if there is an RT thread, locking should be turned on by default. Everything that achieves this can also perform the locking at any desired point during setup. |
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Move lockpages before setscheduler. Add additional information for lockpages and setscheduler. Reset t_first right before changing scheduling policy so that timers (and in-kernel accounting) is not skewed.