On Apr 13, 2021, at 5:22 PM, Andi Kleen [off-list ref] wrote:

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ms granularity seems very coarse grained for this. Surely
at some point of spinning you can afford a ktime_get? But ok.

We are reading time when we are at the head of the (main) queue, but
don’t have the lock yet. Not sure about the latency of ktime_get(), but
anything reasonably fast but not necessarily precise should work.

Actually cpu_clock / sched_clock (see my other email). These should
be fast without corner cases and also monotonic.

I see, thanks.

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Could you turn that into a moduleparm which can be changed at runtime?
Would be strange to have to reboot just to play with this parameter

Yes, good suggestion, thanks.

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This would also make the code a lot shorter I guess.

So you don’t think we need the command-line parameter, just the module_param?

module_params can be changed at the command line too, so yes.

Got it, thanks again.

— Alex


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