On Mon, 20 Apr 2020 21:01:00 -0500 bijan tabatabai <bijan311@xxxxxxxxx> wrote: > Hi Steve, > > > Won't that while loop just go into a spin? > > > > What about something like a fsnotify on a /proc/<pid>/ file? > > > > I rather have trace-cmd sleep and wake up when a task exits, than to do a > > spin. Like it does for the -F option. > > I just tried doing this using the inotify API and hit a snag. > It turns out inotify can't monitor pseudo-filesystems like /proc, so I > don't think that suggestion will work. > > What if I put a call to sleep in the loop? > It's not the most elegant solution, but that way it wouldn't be too > different from the current code that sleeps for 10 seconds after > checking if finished is set to true. Perhaps using the new pidfd interface may work here. https://lwn.net/Articles/794707/ It was added in 5.4 (which is still rather new), but this would be a new trace-cmd feature as well. -- Steve
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