td_swvoltick

[Konstantin Belousov]

On Fri, Jan 12, 2018 at 01:31:41PM -0600, Eric van Gyzen wrote:
> should_yield() compares thread::td_swvoltick to 'ticks' to determine
> whether a thread is hogging and should yield.  Since td_swvoltick
> records 'ticks' /before/ the actual context switch, the calculation in
> should_yield() includes any time that the thread was switched out.  It
> seems that should_yield() wants to know how long the thread has actually
> been running.  Therefore, td_swvoltick should record 'ticks' /after/
> sched_switch() returns.
> 
> Does this make sense, or am I missing something?
Yes, it does make sense to me.

> 
> If this makes sense, I would probably keep the current assignment in
> mi_switch() and simply add a second assignment after the call to
> sched_switch().  That way, db_show_thread will still show useful data
> for sleeping threads.  I would do the same for td_swinvolticks.
> 
> I'll be happy to make the change myself.  I just want a sanity check
> before I bother.
> 
> Thanks in advance,
> 
> Eric
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